View source for Tornado outbreak of May 18–21, 2013

{{Short description|Tornado outbreak that struck the Midwestern United States on May 18–21, 2013}}
{{Infobox storm
 | name                 = Tornado outbreak of May 18–21, 2013
 | image                = Central Oklahoma supercells 2013-05-20 1940Z.jpg
 | alt                  = 
 | caption              = Multiple supercells associated with the storm system as seen on May&nbsp;20 at 2:40&nbsp;p.m.&nbsp;CDT (1940&nbsp;UTC)
 | type                 = Tornado outbreak
 | active               = May 18–21, 2013 
 | lowest pressure      = 
 | lowest temperature   = 
 | tornadoes            = [[List of tornadoes in the tornado outbreak of May 18–21, 2013|78]]
 | fujitascale          = EF5
 | tornado duration     = 2 days, 17 hours, 42 minutes
 | highest winds        = Tornadic – {{convert|210|mph|km/h|abbr=on}} ([[Moore, Oklahoma|Moore, OK]] EF5 tornado on May 20)<br>Non-tornadic – {{convert|100|mph|km/h|abbr=on}} ([[Milford Lake|Milford Lake, KS]] on May 18)
 | hail                 = {{convert|4.25|in|cm|abbr=on}} in diameter (N of [[Bigheart, Oklahoma|Bigheart, OK]] on May 20) <!-- unused? -->
 | gusts                = 
 | maximum snow         = 
 | power outages        = 
 | total fatalities     = 26 fatalities (+3 non-tornadic; +1 indirect), 229 injuries
 | damages              = $2–5 billion<ref name="Damage">{{cite web|author=Victor Epstein|publisher=DesMoines Register|date=May 24, 2013|accessdate=May 26, 2013|title=Tornado damage estimates skyrocket to $5 billion|url=http://www.desmoinesregister.com/article/20130524/BUSINESS/130524027/Tornado-damage-estimates-skyrocket-5-billion|archive-url=https://archive.today/20130629012806/http://www.desmoinesregister.com/article/20130524/BUSINESS/130524027/Tornado-damage-estimates-skyrocket-5-billion|url-status=dead|archive-date=June 29, 2013}}</ref>{{#tag:ref|Includes damages from the May 15 tornadoes in Texas.|group="nb"}}
 | affected             = 
 | enhanced             = yes
 | partof               = the '''[[Tornadoes of 2013]]'''
}}
A significant and destructive [[tornado outbreak]] that affected parts of the [[Midwestern United States]] and lower [[Great Plains]] in mid-May 2013. This event occurred just days after a [[Tornado outbreak of May 15–17, 2013|deadly outbreak]] struck [[Texas]] and surrounding southern states on May 15. On May 16, a slow moving [[Trough (meteorology)|trough]] crossed the [[Rocky Mountains|Rockies]] and traversed the western Great Plains. Initially, activity was limited to scattered severe storms; however, by May 18, the threat for organized severe thunderstorms and tornadoes greatly increased. A few tornadoes touched down that day in [[Kansas]] and [[Nebraska]], including an EF4 tornado near [[Rozel, Kansas]]. Maintaining its slow eastward movement, the system produced another round of severe weather nearby. Activity significantly increased on May 19, with tornadoes confirmed in [[Oklahoma]], Kansas, [[Iowa]], [[Missouri]], and [[Illinois]]. In Oklahoma, two strong tornadoes, one rated EF4, caused significant damage in rural areas of the eastern [[Oklahoma City metropolitan area]]; two people lost their lives near [[Shawnee, Oklahoma|Shawnee]]. The most dramatic events unfolded on May 20 as a large EF5 tornado devastated parts of [[Moore, Oklahoma]], killing 24 people. Thousands of structures were destroyed, with many being completely flattened. Several other tornadoes occurred during the day in areas further eastward, though the majority were weak and caused little damage.

The severe threat shifted towards damaging straight-line winds on May 21 as a large [[squall line]] developed across the southern states. Further north in [[Ontario]], three tornadoes, including an EF2, touched down. Over the following five days, the system responsible for the outbreak moved very little across the [[Eastern United States]]. By May 24, it virtually stalled off the coast of [[New England]], resulting in several days of heavy rain across the region. It later moved northeastward and was last noted by the [[Weather Prediction Center]] late on May 26 over southeastern [[Canada]]. During the storm's eleven-day trek across the United States, it produced 75 tornadoes, 4 of which were rated EF3 or higher. Over 1,000 reports of damaging winds were received by the [[Storm Prediction Center]] as well. The system's slow movement also resulted in record-breaking rainfall in [[North Dakota]], [[New York (state)|New York]] and [[Vermont]]. Additionally, during the overnight of May 25–26, unusually cold air behind the cyclone resulting in record-late snowfall across northern New England.

Overall, severe weather associated with the storm was responsible for 30 fatalities (26 from tornadoes) and over 200 injuries in the United States. Additionally, damage was estimated to amount to $2–5 billion, making it one of the costliest severe weather events on record.<ref name="Damage"/><ref>{{cite web|work=National Climatic Data Center|publisher=National Oceanic and Atmospheric Administration|year=2013|accessdate=May 27, 2013|title=Billion-Dollar Weather/Climate Disasters|url=http://www.ncdc.noaa.gov/billions/events}}</ref>

==Meteorological synopsis==
{| class="wikitable" style="margin:0 0 0.5em 1em;float:right;"
|-
| colspan="4" style="text-align:center;"| '''Casualties by State'''
|-
!State
!Total
!Fatalities
!Injuries
|-
|style="background:#e6e9ff;" |[[Arkansas]]
|  style="background:#e6e9ff; text-align:right;"| 1
|align="right"| 1<ref name="0520rpt"/>
|align="right"| 0
|-
|style="background:#e6e9ff;" |[[Illinois]]
|  style="background:#e6e9ff; text-align:right;"| 3
|align="right"| 0
|align="right"| 3<ref name="St.LouisMay20">{{cite web|work=National Weather Service Office in St. Louis, Missouri|publisher=National Oceanic and Atmospheric Administration|date=May 21, 2013|accessdate=May 26, 2013|title=Short-lived Tornado Confirmed in Mount Olive Illinois|url=http://www.crh.noaa.gov/news/display_cmsstory.php?wfo=lsx&storyid=94764&source=2}}</ref>
|-
|style="background:#e6e9ff;" |[[Kansas]]
|  style="background:#e6e9ff; text-align:right;"| 2
|align="right"| 0
|align="right"| 2<ref name="NWSTopekaMay1819">{{cite web|work=National Weather Service Office in Topeka, Kansas |publisher=National Oceanic and Atmospheric Administration |date=May 22, 2013 |accessdate=May 23, 2013 |title=May 18 & 19 – Two Days of Severe Weather with Damaging winds and Brief Tornadoes |url=http://www.crh.noaa.gov/news/display_cmsstory.php?wfo%3Dtop%26storyid%3D94710%26source%3D0 |archive-url=https://archive.today/20240522201025/https://www.webcitation.org/6GpcwQjIr?url=http://www.crh.noaa.gov/news/display_cmsstory.php%3Fwfo=top&storyid=94710&source=0 |url-status=dead |archive-date=May 22, 2024 }}</ref>
|-
|style="background:#e6e9ff;" |[[Minnesota]]
|  style="background:#e6e9ff; text-align:right;"| 4
|align="right"| 2<ref name="MNDeaths"/>
|align="right"| 2<ref name="MNDeaths"/>
|-
|style="background:#e6e9ff;" |[[New York (state)|New York]]
|  style="background:#e6e9ff; text-align:right;"| 1
|align="right"| 0
|align="right"| 1<ref name="0522rpt"/>
|-
|style="background:#e6e9ff;" |[[Oklahoma]]
|  style="background:#e6e9ff; text-align:right;"| 405
|align="right"| 26<ref name="ShawneeDeaths">{{cite web|title=2 killed in Oklahoma Sunday tornadoes ID'd|url=http://www.koco.com/news/oklahomanews/around-oklahoma/2-killed-in-oklahoma-sunday-tornadoes-idd/-/12530084/20219414/-/hayin1z/-/index.html|archive-url=https://archive.today/20130615230433/http://www.koco.com/news/oklahomanews/around-oklahoma/2-killed-in-oklahoma-sunday-tornadoes-idd/-/12530084/20219414/-/hayin1z/-/index.html|url-status=dead|archive-date=June 15, 2013|publisher=[[KOCO-TV]]|accessdate=May 20, 2013|date=May 20, 2013}}</ref><ref name="ReutersMay22"/>
|align="right"| 377<ref name="OklaInjured">{{cite news|author1=Josh Levs  |author2=Steve Almasy |name-list-style=amp |publisher=CNN|date=May 24, 2013|accessdate=May 27, 2013|title=Students, teachers from tornado-leveled school say goodbye |url=http://www.cnn.com/2013/05/23/us/oklahoma-tornado-main/index.html?hpt=hp_t2}}</ref>
|-
|style="background:#e6e9ff;" |[[Tennessee]]
|  style="background:#e6e9ff; text-align:right;"| 1
|align="right"| 0
|align="right"| 1<ref name="0521rpt"/>
|-
|style="background:#e6e9ff;" |[[West Virginia]]
|  style="background:#e6e9ff; text-align:right;"| 2
|align="right"| 0
|align="right"| 2<ref name="0522rpt"/>
|-
|style="background:#e6e9ff;"|Totals
|  style="background:#e6e9ff; text-align:right;"|'''419'''
|align="right"| 29
|align="right"| 390
|-
| colspan="4" style="text-align:center;"|<small>Totals are inclusive of all events related to the overall system.</small>
|}

The cause of the outbreak was a large, slow-moving [[Trough (meteorology)|trough]], an associated [[cold front]], and several [[Shortwave (meteorology)|shortwave troughs]] that triggered severe weather from the Rockies eastward to New England and from Canada southward to the [[Gulf Coast of the United States]]. The system impacted the United States and Canada from May 16–26 and produced tornadoes on five of the eleven days. During this nearly two-week-long event, the Storm Prediction Center (SPC) received 1,967 reports of severe weather: 101 for tornadoes, 1,176 for wind, and 690 for [[hail]]. Some of these reports were associated with a separate system over the [[Southeastern United States]] on May 19–20.

===May 16–17===
The first indications of a possible [[tornado outbreak]] came on May 13 as [[Numerical weather prediction|weather forecast models]] began depicting a multi-day severe weather event across the [[Central United States]].<ref>{{cite web|author=Stephen Goss|work=Storm Prediction Center|publisher=National Oceanic and Atmospheric Administration|date=May 13, 2013|accessdate=May 21, 2013|title=Day 4–8 Severe Weather Outlook Issued on May 13, 2013|url=http://www.spc.noaa.gov/products/exper/day4-8/archive/2013/day4-8_20130513.html}}</ref> On May 16, a shortwave trough, along with a [[weather front|surface front]] emerged from the Rockies into the [[High Plains (United States)|High Plains]]. Only scattered thunderstorms accompanied the system, with few reaching severe levels.<ref>{{cite web|author1=Steven J. Weiss  |author2=Ariel E. Cohen |name-list-style=amp |work=Storm Prediction Center|publisher=National Oceanic and Atmospheric Administration|date=May 16, 2013|accessdate=May 22, 2013|title=May 16, 2013 1630 UTC Day 1 Convective Outlook|url=http://www.spc.noaa.gov/products/outlook/archive/2013/day1otlk_20130516_1630.html}}</ref> Only 13 reports of large hail and damaging winds in [[Colorado]], [[Kansas]], and [[Nebraska]], were received by the SPC.<ref name="0516rpt">{{cite web|work=Storm Prediction Center|publisher=National Oceanic and Atmospheric Administration|date=May 22, 2013|accessdate=May 22, 2013|title=20130516's Storm Reports (1200 UTC − 1159 UTC)|url=http://www.spc.noaa.gov/climo/reports/130515_rpts.html}}</ref> On May 17, a slow-moving [[Trough (meteorology)|mid- to upper-level trough]] in the same region brought a further risk of thunderstorms. Significant low-level moisture streamed northward from [[Texas]] into [[the Dakotas]] ahead of the system. This increased [[dew point]]s in the area into the {{convert|50|F|C|abbr=on}} range; [[orographic lift]] and up-slope flow was expected to trigger the development of storms. The SPC issued a small [[Storm Prediction Center#Categories|slight risk]] for severe thunderstorms around the [[Black Hills]] into central Nebraska, with the main threat being large hail and the possibility of an isolated tornado. A second slight risk area was issued over central Texas as the northward flow collided with a dry line in the area.<ref>{{cite web|author1=Bryan T. Smith  |author2=Patrick Marsh |name-list-style=amp |work=Storm Prediction Center|publisher=National Oceanic and Atmospheric Administration|date=May 17, 2013|accessdate=May 22, 2013|title=May 17, 2013 0600 UTC Day 1 Convective Outlook|url=http://www.spc.noaa.gov/products/outlook/archive/2013/day1otlk_20130517_1200.html}}</ref><ref>{{cite web|author=Steven J. Weiss|work=Storm Prediction Center|publisher=National Oceanic and Atmospheric Administration|date=May 17, 2013|accessdate=May 22, 2013|title=May 17, 2013 1630 UTC Day 1 Convective Outlook|url=http://www.spc.noaa.gov/products/outlook/archive/2013/day1otlk_20130517_1630.html}}</ref> Though there was notable [[Inversion (meteorology)|atmospheric capping]], [[convective available potential energy]] (CAPE) values of 2,500–3,000 [[Joule|J]]/[[Kilogram|kg]] led to the potential of localized [[supercell]]s capable of producing very large hail and [[downburst]]s.<ref>{{cite web|author1=Gregory Carbin |author2=Steven J. Weiss |name-list-style=amp |work=Storm Prediction Center |publisher=National Oceanic and Atmospheric Administration |date=May 17, 2013 |accessdate=May 22, 2013 |title=Mesoscale Discussion 668 |url=http://www.spc.noaa.gov/products/md/md0668.html |url-status=live |archiveurl=https://web.archive.org/web/20040601223604/http://www.spc.noaa.gov/products/md/md0668.html |archivedate=June 1, 2004 }}</ref> Additionally, a stationary [[outflow boundary]] over southern [[Minnesota]] and northern [[Iowa]] encountered moderate instability and produced scattered severe storms, some of which were capable of producing tornadoes.<ref>{{cite web|author1=Andrew Dean |author2=Steven J. Weiss |name-list-style=amp |work=Storm Prediction Center |publisher=National Oceanic and Atmospheric Administration |date=May 17, 2013 |accessdate=May 22, 2013 |title=Mesoscale Discussion 671 |url=http://www.spc.noaa.gov/products/md/md0671.html |url-status=live |archiveurl=https://web.archive.org/web/20010124132300/http://www.spc.noaa.gov/products/md/md0671.html |archivedate=January 24, 2001 }}</ref> Two tornadoes were confirmed in [[Young County, Texas]]: one EF1 and one EF0 (these tornadoes were only partially associated with the main system).<ref>{{cite web|work=National Weather Service Office in Fort Worth, Texas|publisher=Iowa Environmental Mesonet|date=May 18, 2013|accessdate=May 23, 2013|title=NWS Damage Survey for 5/17/2013 Young County Tornado Event|url=http://mesonet.agron.iastate.edu/wx/afos/p.php?pil=PNSFWD&e=201305190124}}</ref> Throughout the day, the SPC received a total of 103 reports of severe weather in association with the system: 10 for tornadoes, 21 for wind, and 86 for hail. The tornadoes were not fully associated with the main system.<ref name="0517rpt">{{cite web|work=Storm Prediction Center|publisher=National Oceanic and Atmospheric Administration|date=May 22, 2013|accessdate=May 22, 2013|title=20130517's Storm Reports (1200 UTC − 1159 UTC)|url=http://www.spc.noaa.gov/climo/reports/130517_rpts.html}}</ref>

===May 18===
{{See also|List of tornadoes in the tornado outbreak of May 18–21, 2013#May 18 event}}
[[File:May 18, 2013 Rozel, Kansas tornado damage.jpg|thumb|left|Damage caused by an EF4 tornado near [[Rozel, Kansas]] on May 18.]]
On May 17, the SPC issued a [[Storm Prediction Center#Categories|moderate risk]] of severe weather for northwestern Kansas and southwestern Nebraska for the following day.<ref>{{cite web|author=Mark Darrow|work=Storm Prediction Center|publisher=National Oceanic and Atmospheric Administration|date=May 17, 2013|accessdate=May 21, 2013|title=May 17, 2013 1730 UTC Day 2 Convective Outlook|url=http://www.spc.noaa.gov/products/outlook/archive/2013/day2otlk_20130517_1730.html}}</ref> This was later extended southward into western Oklahoma. On May 18, the trough continued to slowly move from the Rockies into the Great Plains region. Extreme instability ahead of it, with CAPE values reaching 4,000–5,000 J/kg along with strong [[Diabatic representation|diabatic]] heating, was anticipated to spark widespread severe thunderstorms and some supercells. The main threat on May 18 was large hail and [[Downburst|straight-line winds]], with a lesser concern for tornadoes.<ref>{{cite web|author1=Bryan T. Smith  |author2=Patrick Marsh |name-list-style=amp |work=Storm Prediction Center|publisher=National Oceanic and Atmospheric Administration|date=May 18, 2013|accessdate=May 21, 2013|title=May 18, 2013 0600 UTC Day 1 Convective Outlook|url=http://www.spc.noaa.gov/products/outlook/archive/2013/day1otlk_20130518_1200.html}}</ref> The first [[tornado watch]] was issued at 2:45&nbsp;p.m. [[Central Time Zone|CDT]] (1945 [[Coordinated Universal Time|UTC]]) for much of western Nebraska, Kansas, and extreme northeast [[Colorado]] as moist northerly flow ahead of the trough met up with a [[dry line]] moving into the region. Tornadic activity was expected to be relatively limited at first, though a strengthening [[Jet stream|low-level jet]] along with increasing [[relative humidity]] along the [[boundary layer]] would provide more favorable conditions for development.<ref>{{cite web|author=Brynn Kerr |work=Storm Prediction Center |publisher=National Oceanic and Atmospheric Administration |date=May 18, 2013 |accessdate=May 22, 2013 |title=Tornado Watch 170 |url=http://www.spc.noaa.gov/products/watch/ww0170.html |url-status=live |archiveurl=https://web.archive.org/web/20000511042813/http://www.spc.noaa.gov/products/watch/ww0170.html |archivedate=May 11, 2000 }}</ref>

During the evening of May 18, tornadoes touched down in parts of Kansas and Nebraska. However, most remained in open country, causing little damage.<ref name="0518rpt">{{cite web|work=Storm Prediction Center|publisher=National Oceanic and Atmospheric Administration|date=May 20, 2013|accessdate=May 20, 2013|title=20130518's Storm Reports (1200 UTC − 1159 UTC)|url=http://www.spc.noaa.gov/climo/reports/130518_rpts.html}}</ref> Around 5:30&nbsp;p.m. CDT (2230 UTC), a supercell thunderstorm developed to the northeast of [[Dodge City, Kansas|Dodge City]]. At 7:18&nbsp;p.m. CDT (0018 UTC), it spawned a large EF4 tornado near [[Rozel, Kansas]]; one home was largely destroyed and five farms were damaged. Around the time it reached EF4 intensity,<ref name="NWSDodgeCity">{{cite web|work=National Weather Service Office in Dodge City, Kansas |publisher=National Oceanic and Atmospheric Administration |date=May 23, 2013 |accessdate=May 25, 2013 |title=EF4 Tornado Impacts Locations Near Rozel Kansas |url=http://www.crh.noaa.gov/news/display_cmsstory.php?wfo%3Dddc%26storyid%3D94702%26source%3D0 |archive-url=https://web.archive.org/web/20130909202016/http://www.crh.noaa.gov/news/display_cmsstory.php?wfo=ddc&storyid=94702&source=0 |url-status=dead |archive-date=September 9, 2013 }}</ref> the tornado took a sharp northward turn as it passed within {{convert|1|mi|km}} of Rozel. Aaron Johnson of the National Weather Service in Dodge City stated that had it not made the turn, Rozel would have likely been destroyed.<ref>{{cite web|author=Keith Miles|publisher=Kansas First News|date=May 28, 2013|accessdate=May 28, 2013|title=Tiny Kansas town has close call with monster tornado|url=http://www.kansasfirstnews.com/2013/05/27/tiny-kansas-town-has-close-call-with-monster-tornado/|archive-url=https://web.archive.org/web/20140330220643/http://kansasfirstnews.com/2013/05/27/tiny-kansas-town-has-close-call-with-monster-tornado/|archive-date=March 30, 2014|url-status=dead}}</ref> A second tornado briefly touched down around 7:50&nbsp;p.m. CDT (0050 UTC). By 8:30&nbsp;p.m. CDT (0130 UTC), a squall line began developing over south-central Nebraska and central Kansas.<ref>{{cite web|author1=Bryan T. Smith |author2=Stephen Corfidi |name-list-style=amp |work=Storm Prediction Center |publisher=National Oceanic and Atmospheric Administration |date=May 18, 2013 |accessdate=May 22, 2013 |title=Mesoscale Discussion 684 |url=http://www.spc.noaa.gov/products/md/md0684.html |url-status=live |archiveurl=https://web.archive.org/web/20050426143218/http://www.spc.noaa.gov/products/md/md0684.html |archivedate=April 26, 2005 }}</ref> Several corridors of intense winds, possibly associated with brief tornadoes, were observed in [[Clay County, Kansas|Clay]] and [[Washington County, Kansas|Washington]] counties in Kansas. Several homes were damaged or destroyed by the winds. Near [[Milford Lake]], a non-tornadic gust of {{convert|100|mph|km/h|abbr=on}} was measured; two people were injured near the lake after their camper tipped over.<ref name="NWSTopekaMay1819"/> Later on, strong southerly flow and [[Isentropic process|isentropic lift]] intersected a [[stationary front]] over northern [[South Dakota]], southern [[North Dakota]], and western [[Minnesota]], allowing for scattered severe storms to develop.<ref>{{cite web|author1=Bryan T. Smith |author2=Stephen Corfidi |name-list-style=amp |work=Storm Prediction Center |publisher=National Oceanic and Atmospheric Administration |date=May 18, 2013 |accessdate=May 22, 2013 |title=Mesoscale Discussion 689 |url=http://www.spc.noaa.gov/products/md/md0689.html |url-status=live |archiveurl=https://web.archive.org/web/20040601223232/http://www.spc.noaa.gov/products/md/md0689.html |archivedate=June 1, 2004 }}</ref> One of these storms produced gusts up to {{convert|85|mph|km/h|abbr=on}} to the east of [[Okreek, South Dakota]]. Throughout the day, the SPC received a total of 231 reports of severe weather: 24 for tornadoes, 92 for wind, and 115 for hail.<ref name="0518rpt"/>

===May 19===
{{See also|List of tornadoes in the tornado outbreak of May 18–21, 2013#May 19 event}}
[[Image:GOES13 Visible 2013-05-19 231018Z.jpg|thumb|right|Visible satellite imagery of the severe thunderstorms at 6:10 p.m. CDT on May 19.]]
On May 19, the trough moved only slightly eastward, with many of the same areas impacted on May 18 being threatened again. During the day, two [[Low-pressure area|areas of low pressure]] developed along the trough: one over the north-central plains and the other over Oklahoma. A large plume of steep [[Lapse rate|mid-level lapse rates]] accompanied by deep moisture (with dew points in some areas exceeding {{convert|70|F|C|abbr=on}}) spread across much of the central and southern plains into the [[Mississippi River Valley]]. Thunderstorms in these areas were expected to develop early, though not be particularly widespread or damaging. The most intense storms were anticipated over the southern [[Missouri River Valley]] where strong daytime heating and "aggressive destabilization" would take place. Additionally, a diurnally strong jet and strong [[wind shear]] favored the development of long-lived supercells capable of producing large hail and tornadoes, some potentially violent. Activity was expected to become associated with a squall line by the evening as the cold front moved slowly eastward. In light of that, the SPC issued a moderate risk of severe thunderstorms for south-central Oklahoma, eastern Kansas, western Missouri, and extreme southeastern Nebraska.<ref>{{cite web|author1=Jared L. Guyer  |author2=Patrick Marsh |name-list-style=amp |work=Storm Prediction Center|publisher=National Oceanic and Atmospheric Administration|date=May 19, 2013|accessdate=May 22, 2013|title=May 19, 2013 0600 UTC Day 1 Convective Outlook|url=http://www.spc.noaa.gov/products/outlook/archive/2013/day1otlk_20130519_1200.html}}</ref>

By the afternoon hours, rapid destabilization of the boundary layer began across eastern Kansas, prompting a tornado watch for the area.<ref>{{cite web|author=Brynn Kerr |work=Storm Prediction Center |publisher=National Oceanic and Atmospheric Administration |date=May 19, 2013 |accessdate=May 23, 2013 |title=Tornado Watch 181 |url=http://www.spc.noaa.gov/products/watch/ww0181.html |url-status=live |archiveurl=https://web.archive.org/web/20030403001312/http://www.spc.noaa.gov/products/watch/ww0181.html |archivedate=April 3, 2003 }}</ref> Further south in Oklahoma, a rapidly mixing dry line accompanied by a deepening surface low moved eastward into an area with deep moisture. Though leftover outflow boundaries from the previous day's storms and capping limited initial [[Atmospheric convection|convective activity]], strong daytime heating would soon allow storms to break the cap.<ref>{{cite web|author1=Jaret W. Rogers |author2=Brynn Kerr |name-list-style=amp |work=Storm Prediction Center |publisher=National Oceanic and Atmospheric Administration |date=May 19, 2013 |accessdate=May 23, 2013 |title=Mesoscale Discussion 698 |url=http://www.spc.noaa.gov/products/md/md0698.html |url-status=live |archiveurl=https://web.archive.org/web/20030402214627/http://www.spc.noaa.gov/products/md/md0698.html |archivedate=April 2, 2003 }}</ref> A tornado watch was issued for the central third of Oklahoma at 2:15&nbsp;p.m. CDT (1915 UTC), with the SPC noting the risk for potentially long-lived supercells and a few strong tornadoes.<ref>{{cite web|author=Brynn Kerr |work=Storm Prediction Center |publisher=National Oceanic and Atmospheric Administration |date=May 19, 2013 |accessdate=May 23, 2013 |title=Tornado Watch 182 |url=http://www.spc.noaa.gov/products/watch/ww0182.html |url-status=live |archiveurl=https://web.archive.org/web/20020503131045/http://www.spc.noaa.gov/products/watch/ww0182.html |archivedate=May 3, 2002 }}</ref> Around 2:30&nbsp;p.m. CDT (1930 UTC), a supercell developed over [[Harper County, Kansas]] and tracked northeastward. This cell produced three short-lived tornadoes, including an EF2 to the southwest of [[Wichita, Kansas|Wichita]] that prompted a [[tornado emergency]] for the city.<ref name="NWSWichitaMay19">{{cite web|work=National Weather Service Office in Wichita, Kansas |publisher=National Oceanic and Atmospheric Administration |date=May 23, 2013 |accessdate=May 23, 2013 |title=May 19th south central Kansas tornadoes |url=http://www.crh.noaa.gov/news/display_cmsstory.php?wfo%3Dict%26storyid%3D94701%26source%3D0 |archive-url=https://web.archive.org/web/20150415204700/http://www.crh.noaa.gov/news/display_cmsstory.php?wfo=ict&storyid=94701&source=0 |url-status=dead |archive-date=April 15, 2015 }}</ref><ref name="WichitaWarning">{{cite web|work=National Weather Service Office in Wichita, Kansas|publisher=Iowa Environmental Mesonet|date=May 19, 2013|accessdate=May 20, 2013|title=Severe Weather Statement: Tornado Warning|url=http://mesonet.agron.iastate.edu/vtec/#2013-O-NEW-KICT-TO-W-0007/USCOMP-N0Q-201305192025}}</ref> Over the course of three hours, 10 other tornadoes touched down across the state, none of which exceeded EF1 intensity.<ref name="NWSTopekaMay1819"/><ref name="NWSWichitaMay19"/>

By 4:30&nbsp;p.m. CDT (2130 UTC), the risk for significant tornadoes markedly increased over [[central Oklahoma]], especially around the Oklahoma City metropolitan area. Maximized pressure falls ahead of the dry line allowed several storms to acquire intense updrafts and develop into rotating supercells within the state. Very strong low-level [[mesocyclone]]s were expected to develop with these storms, with several tornadoes touching down.<ref>{{cite web|author=Bryan T. Smith |work=Storm Prediction Center |publisher=National Oceanic and Atmospheric Administration |date=May 19, 2013 |accessdate=May 23, 2013 |title=Mesoscale Discussion 703 |url=http://www.spc.noaa.gov/products/md/md0703.html |url-status=live |archiveurl=https://web.archive.org/web/20040819201633/http://www.spc.noaa.gov/products/md/md0703.html |archivedate=August 19, 2004 }}</ref> Around this time, tornadoes began touching down around the city. At 4:41&nbsp;p.m. CDT (2141 UTC), a large EF3 tornado developed {{convert|3|mi|km|abbr=on}} northwest of [[Luther, Oklahoma|Luther]] and tracked for roughly {{convert|20|mi|km|abbr=on}}. To the southeast, a violent EF4 tornado formed around 6:00&nbsp;p.m. CDT (2300 UTC) over [[Cleveland County, Oklahoma|Cleveland County]]. That storm was the strongest of the day and resulted in significant damage, especially near the city of [[Shawnee, Oklahoma|Shawnee]] where two people were killed. Two other tornadoes touched down during the evening in eastern Oklahoma: one EF2 and one EF1.<ref name="NWSNormanMay19">{{cite web|work=National Weather Service Office in Norman, Oklahoma|publisher=National Oceanic and Atmospheric Administration|date=May 23, 2013|accessdate=May 26, 2013|title=The Tornado Outbreak of May 19, 2013|url=http://www.srh.noaa.gov/oun/?n=events-20130519}}</ref><ref name="NWSTulsaMay19">{{cite web|work=National Weather Service Office in Tulsa, Oklahoma|publisher=National Oceanic and Atmospheric Administration|date=May 24, 2013|accessdate=May 25, 2013|title=NWS Damage Survey for 05/19/2013 Tornado Event|url=http://www.srh.noaa.gov/tsa/?n=weather-event_2013may19}}</ref> In addition to the two fatalities, 39 people were injured across the state.<ref>{{cite web|author=Julianna Goldman |publisher=Bloomberg Businessweek News |date=May 27, 2013 |accessdate=May 27, 2013 |title=Obama Pledges Assistance While Touring Oklahoma Tornado Damage |url=http://www.businessweek.com/news/2013-05-26/obama-pledges-assistance-while-touring-oklahoma-tornado-damage |url-status=dead |archiveurl=https://archive.today/20240522201349/https://www.webcitation.org/6GvlcZBmZ?url=http://www.businessweek.com/news/2013-05-26/obama-pledges-assistance-while-touring-oklahoma-tornado-damage |archivedate=May 22, 2024 }}</ref>

[[File:May 19, 2013 SW Wichita supercell.jpg|thumb|left|Radar image of a supercell thunderstorm to the southwest of Wichita, Kansas at 3:32 p.m. CDT (2032 UTC) that spawned an EF2 tornado.]]
Storm coverage over eastern Kansas soon increased as well, with the main threat being damaging winds.<ref>{{cite web|author=Bryan T. Smith |work=Storm Prediction Center |publisher=National Oceanic and Atmospheric Administration |date=May 19, 2013 |accessdate=May 23, 2013 |title=Mesoscale Discussion 704 |url=http://www.spc.noaa.gov/products/md/md0704.html |url-status=live |archiveurl=https://web.archive.org/web/20030422211825/http://www.spc.noaa.gov/products/md/md0704.html |archivedate=April 22, 2003 }}</ref> Further north over parts of Iowa and Minnesota, a mid-level vortex over the region accompanied by scattered thunderstorms presented a risk of severe storms. Increasing wind shear and an influx of moist air from the south was expected to allow convection to persist over the region for much of the evening, with the main threat being damaging winds and a few tornadoes.<ref>{{cite web|author=Corey M. Mead |work=Storm Prediction Center |publisher=National Oceanic and Atmospheric Administration |date=May 19, 2013 |accessdate=May 23, 2013 |title=Mesoscale Discussion 705 |url=http://www.spc.noaa.gov/products/md/md0705.html |url-status=live |archiveurl=https://web.archive.org/web/20080426230443/http://www.spc.noaa.gov/products/md/md0705.html |archivedate=April 26, 2008 }}</ref> By the evening hours, several squall lines developed across the region. Unstable air over much of Missouri allowed for these storms to maintain themselves as they moved slowly eastward.<ref>{{cite web|author1=Bryan T. Smith |author2=Stephen Corfidi |name-list-style=amp |work=Storm Prediction Center |publisher=National Oceanic and Atmospheric Administration |date=May 19, 2013 |accessdate=May 23, 2013 |title=Mesoscale Discussion 707 |url=http://www.spc.noaa.gov/products/md/md0707.html |url-status=live |archiveurl=https://web.archive.org/web/20040601222940/http://www.spc.noaa.gov/products/md/md0707.html |archivedate=June 1, 2004 }}</ref> Around 7:00&nbsp;p.m. CDT (0000 UTC), a rapidly moving vorticity maximum over Iowa resulted in a significant increase in thunderstorms over the area, some of which were tornadic.<ref>{{cite web|author=Corey M. Mead |work=Storm Prediction Center |publisher=National Oceanic and Atmospheric Administration |date=May 19, 2013 |accessdate=May 23, 2013 |title=Mesoscale Discussion 710 |url=http://www.spc.noaa.gov/products/md/md0710.html |url-status=live |archiveurl=https://web.archive.org/web/20030423001737/http://www.spc.noaa.gov/products/md/md0710.html |archivedate=April 23, 2003 }}</ref> The most intense cell tracked from [[Dallas County, Iowa|Dallas County]] to [[Story County, Iowa|Story County]], producing three brief tornadoes and straight-line winds along its path.<ref name="NWSDesMoines">{{cite web|work=National Weather Service Office in Des Moines, Iowa|publisher=National Oceanic and Atmospheric Administration|date=May 2013|accessdate=May 23, 2013|title=Storm Survey Results from Dallas, Polk, and Story Counties|url=http://www.crh.noaa.gov/images/dmx/StormSurveys/2013/StormSurvey_5192013.pdf}}</ref> The touchdowns in Iowa marked the end of a record 358-day span with no tornadoes in the state.<ref>{{cite web|publisher=KCRG9|date=May 20, 2013|accessdate=May 20, 2013|title=No one Injured in Central Iowa Tornadoes|url=http://www.kcrg.com/news/local/No-one-Injured-in-Central-Iowa-Tornadoes-208110961.html|url-status=dead|archiveurl=https://web.archive.org/web/20130619191333/http://www.kcrg.com/news/local/No-one-Injured-in-Central-Iowa-Tornadoes-208110961.html|archivedate=June 19, 2013}}</ref><ref>{{cite web|author=Stephanie Moore|publisher=WHOTV-13|date=May 19, 2013|accessdate=May 20, 2013|title=Record Ends: Tornadoes Hit Iowa|url=http://whotv.com/2013/05/19/record-ends-tornadoes-hit-iowa/}}</ref>

Severe activity began decreasing by 10:00&nbsp;p.m. CDT (0300 UTC) as the main squall line over Missouri entered an area of increased capping.<ref>{{cite web|author=Bryan T. Smith |work=Storm Prediction Center |publisher=National Oceanic and Atmospheric Administration |date=May 19, 2013 |accessdate=May 23, 2013 |title=Mesoscale Discussion 719 |url=http://www.spc.noaa.gov/products/md/md0719.html |url-status=live |archiveurl=https://web.archive.org/web/20031018035237/http://www.spc.noaa.gov/products/md/md0719.html |archivedate=October 18, 2003 }}</ref> A secondary line, extending northward into [[Wisconsin]], behind it with bowing segments, indicative of locally intense winds, produced additional damaging winds, though it gradually weakened during the overnight of May 19–20.<ref>{{cite web|author=Bryan T. Smith |work=Storm Prediction Center |publisher=National Oceanic and Atmospheric Administration |date=May 19, 2013 |accessdate=May 23, 2013 |title=Mesoscale Discussion 720 |url=http://www.spc.noaa.gov/products/md/md0720.html |url-status=live |archiveurl=https://web.archive.org/web/20020510110201/http://www.spc.noaa.gov/products/md/md0720.html |archivedate=May 10, 2002 }}</ref><ref>{{cite web|author1=Jeffrey L. Peters |author2=John A. Hart |name-list-style=amp |work=Storm Prediction Center |publisher=National Oceanic and Atmospheric Administration |date=May 20, 2013 |accessdate=May 23, 2013 |title=Mesoscale Discussion 722 |url=http://www.spc.noaa.gov/products/md/md0722.html |url-status=live |archiveurl=https://web.archive.org/web/20030404022609/http://www.spc.noaa.gov/products/md/md0722.html |archivedate=April 4, 2003 }}</ref> Throughout the day, the SPC received a total of 558 reports of severe weather: 34 for tornadoes, 325 for wind, and 199 for hail; however, some of the wind and hail reports were associated with a separate system over the Southeastern United States.<ref name="0519rpt">{{cite web|work=Storm Prediction Center|publisher=National Oceanic and Atmospheric Administration|date=May 23, 2013|accessdate=May 23, 2013|title=20130519's Storm Reports (1200 UTC − 1159 UTC)|url=http://www.spc.noaa.gov/climo/reports/130519_rpts.html}}</ref>
{{clear}}

===May 20===
{{See also|List of tornadoes in the tornado outbreak of May 18–21, 2013#May 20 event}}
On May 20, a prominent central upper trough moved eastward with a lead upper low pivoting over the Dakotas and Upper Midwest. A Southern stream shortwave trough/moderately strong polar jet moved east-northeastward over the southern Rockies to the southern Great Plains and Ozarks area, with severe thunderstorms likely with peak heating. The Storm Prediction Center issued a moderate risk of severe thunderstorms during the early morning hours of May 20 from southeastern [[Missouri]] to north-central Texas, for the possibility of isolated strong tornadoes across central and eastern Oklahoma, in addition to the threat of large hail and damaging straight-line wind gusts.<ref>{{cite web|title=May 20, 2013 0600 UTC Day 1 Convective Outlook|url=http://www.spc.noaa.gov/products/outlook/archive/2013/day1otlk_20130520_1200.html|publisher=Storm Prediction Center|accessdate=2013-05-20|date=2013-05-20}}</ref>

The most devastating event of the day occurred when a violent EF5 tornado struck [[Moore, Oklahoma]], damaging or destroying more than 13,000 homes and killing 25 people including seven children who died while taking shelter inside Plaza Towers Elementary School,<ref>{{Cite web |date=2015-06-01 |title=Two Years Later, New Book Tells Stories Of 'Merciless' May 2013 Tornadoes |url=https://www.kgou.org/weather-and-climate/2015-06-01/two-years-later-new-book-tells-stories-of-merciless-may-2013-tornadoes |access-date=2024-08-23 |website=KGOU |language=en}}</ref> which was flattened by the tornado.<ref>{{Cite web |last=Montgomery |first=Shelby |date=2022-05-20 |title=Friday marks nine years since EF5 tornado hit Moore, killing 7 children |url=https://www.koco.com/article/oklahoma-deadly-moore-tornado-nine-years-later/40058026 |access-date=2024-06-11 |website=KOCO |language=en}}</ref><ref>{{Cite web |last=Brumfield |first=Ben |date=2014-05-20 |title=Moore, Oklahoma, looks back on tornado that killed 24 one year ago |url=https://www.cnn.com/2014/05/20/us/oklahoma-moore-tornado-anniversary/index.html |access-date=2024-06-11 |website=CNN |language=en}}</ref>

In [[Michigan]], gusts from the squall line reached {{convert|80|mph|km/h|abbr=on}}, downing numerous trees and power lines. Some trees were {{convert|1.5|ft|m}} in diameter. A few trucks were blown onto their sides as well.<ref name="0520rpt"/> Roughly 30,000 customers of [[Consumers Energy]] lost power across the state.<ref>{{cite web|author=Brad Devereaux|publisher=Michigan Live|date=May 21, 2013|accessdate=May 28, 2013|title=Wind leaves thousands without power in northern Michigan; Consumers Energy says service should be restored by 11 p.m.|url=http://www.mlive.com/news/saginaw/index.ssf/2013/05/high_winds_leave_thousands_wit.html}}</ref> Further south, considerable damage took place across Missouri and Arkansas due to a squall line. Gusts reached {{convert|88|mph|km/h|abbr=on}} in [[Hannibal, Missouri]]. One person was killed in [[Springdale, Arkansas]] after his vehicle was struck by wind-driven debris.<ref name="0520rpt"/> Several tornadoes touched down within this squall line in the two states, none of which exceeded EF1 intensity.<ref name="NWSTulsaMay19"/><ref name="NWSSpringfield">{{cite web|work=National Weather Service Office in Springfield, Missouri|publisher=National Oceanic and Atmospheric Administration|date=May 23, 2013|accessdate=May 25, 2013|title=Severe Weather Event May 19–20 2013: Tornado Surveys|url=http://www.crh.noaa.gov/sgf/scripts/localdata.php?loc=appevents&data=2013/2013may20/survey.htm&format=noprint}}</ref> The squall line continued to produce damaging winds as it progressed eastward into Illinois and Indiana.<ref name="0520rpt"/> Three additional tornadoes touched down into the early hours of May 21, including a brief EF2 in [[Mount Olive, Illinois]] around 10:14&nbsp;p.m. CDT (0314 UTC).<ref name="St.LouisMay20"/><ref name="NWSIndianapolis">{{cite web|work=National Weather Service Office in Indianapolis, Indiana |publisher=National Oceanic and Atmospheric Administration |date=May 22, 2013 |accessdate=May 25, 2013 |title=Storm Survey Reveals Tornado Damage |url=http://www.crh.noaa.gov/news/display_cmsstory.php?wfo%3Dind%26storyid%3D94762%26source%3D0 |archive-url=https://web.archive.org/web/20160304082557/http://www.crh.noaa.gov/news/display_cmsstory.php?wfo=ind&storyid=94762&source=0 |url-status=dead |archive-date=March 4, 2016 }}</ref>

Throughout the day, the SPC received a total of 447 reports of severe weather: 37 for tornadoes, 281 for wind, and 129 for hail; however, some of the wind and hail reports were associated with a separate system over the Southeastern United States.<ref name="0520rpt">{{cite web|work=Storm Prediction Center|publisher=National Oceanic and Atmospheric Administration|date=May 23, 2013|accessdate=May 23, 2013|title=20130520's Storm Reports (1200 UTC − 1159 UTC)|url=http://www.spc.noaa.gov/climo/reports/130520_rpts.html}}</ref>

===May 21===
{{See also|List of tornadoes in the tornado outbreak of May 18–21, 2013#May 21 event}}
[[File:May 16 to 22, 2013 United States Rainfall.jpg|thumb|right|250px|Total precipitation across the United States from May 16–22.]]
Similar to the preceding days, the slow moving trough and associated cold front moved slowly eastward on May 21. Strong instability ahead of the system prompted the SPC to issue a moderate risk of severe thunderstorms for extreme southeast Oklahoma, southwest Arkansas, northwest Louisiana, and northeast Texas; however, the main threat was damaging winds rather than tornadoes. With CAPE values of 2,500–4,000 J/kg and {{convert|50|to|65|mph|km/h|abbr=on}} shear across the region, conditions were once again favorable for the development of supercells capable of producing large hail. Activity was expected to be scattered at first, with some isolated supercells capable of producing tornadoes, but a squall line was anticipated to develop quickly and become the dominant feature. In the [[Northeastern United States|Northeast]] and [[Great Lakes region]], southwesterly flow ahead of the trough brought warm, moist air into the area. Moderate instability, with CAPE values ranging from 1,000 to 2,000 J/kg and steep lapse rates were supporting of damaging straight-line winds, especially across Michigan, New York and [[Massachusetts]].<ref>{{cite web|author1=John Chris Broyles  |author2=Corey M. Mead |name-list-style=amp |work=Storm Prediction Center|publisher=National Oceanic and Atmospheric Administration|date=May 21, 2013|accessdate=May 28, 2013|title=May 21, 2013 0600 UTC Day 1 Convective Outlook|url=http://www.spc.noaa.gov/products/outlook/archive/2013/day1otlk_20130521_1200.html}}</ref> Later on, instability increased in the Northeast along a quasi-stationary front, leading to the risk of isolated supercells and a [[mesoscale convective system]].<ref>{{cite web|author1=Jeremy S. Grams  |author2=Jaret W. Rogers |name-list-style=amp |work=Storm Prediction Center|publisher=National Oceanic and Atmospheric Administration|date=May 21, 2013|accessdate=May 28, 2013|title=May 21, 2013 1630 UTC Day 1 Convective Outlook|url=http://www.spc.noaa.gov/products/outlook/archive/2013/day1otlk_20130521_1630.html}}</ref>

During the morning of May 21, a strong shortwave trough over the [[Texas Panhandle]] moved eastward into Oklahoma. Moderate instability in the region led to the formation of thunderstorms across the state, with strong thunderstorms developing near the Oklahoma City metropolitan area, including the devastated city of Moore.<ref>{{cite web|author1=Ryan E. Jewell  |author2=Brynn Kerr |name-list-style=amp |work=Storm Prediction Center|publisher=National Oceanic and Atmospheric Administration|date=May 21, 2013|accessdate=May 21, 2013|title=Mesoscale Discussion 748|url=http://www.spc.noaa.gov/products/md/md0748.html}}</ref>

Ahead of the main line of storms, a loosely organized squall line formed over central Tennessee by 11:15&nbsp;a.m. CDT (1615 UTC). Initiating along the edge of an old outflow boundary,<ref>{{cite web|author1=Jaret W. Rogers |author2=Brynn Kerr |name-list-style=amp |work=Storm Prediction Center |publisher=National Oceanic and Atmospheric Administration |date=May 21, 2013 |accessdate=May 28, 2013 |title=Mesoscale Discussion 750 |url=http://www.spc.noaa.gov/products/md/md0750.html |url-status=live |archiveurl=https://web.archive.org/web/20030402175527/http://www.spc.noaa.gov/products/md/md0750.html |archivedate=April 2, 2003 }}</ref> the system moved into an area with CAPE values of 2,000–3,000 J/kg and strong daytime heating. As it moved east-northeastward, it became increasingly intense and organized.<ref>{{cite web|author1=Jaret W. Rogers |author2=Brynn Kerr |name-list-style=amp |work=Storm Prediction Center |publisher=National Oceanic and Atmospheric Administration |date=May 21, 2013 |accessdate=May 28, 2013 |title=Mesoscale Discussion 754 |url=http://www.spc.noaa.gov/products/md/md0754.html |url-status=live |archiveurl=https://web.archive.org/web/20030901053028/http://www.spc.noaa.gov/products/md/md0754.html |archivedate=September 1, 2003 }}</ref> Widespread wind damage occurred from central Tennessee into eastern Kentucky. The highest winds associated with this line reached {{convert|77|mph|km/h|abbr=on}}. Numerous trees and power lines were downed across both states. One person was injured in [[Wilson County, Tennessee]] after a construction crane was blown over onto a car by high winds.<ref name="0521rpt"/>

Severe storms extended into Ontario, Canada, where a squall line produced some damage. Strong winds downed many trees and power lines, leaving roughly 3,000 people without power. Heavy rains also caused some flooding, leaving cars stranded.<ref>{{cite news|author=Canadian Press|newspaper=National Post|date=May 22, 2013|accessdate=May 23, 2013|title=3,000 plus left without electricity in central Ontario after thunderstorms|location=Toronto, Canada|url=http://news.nationalpost.com/2013/05/22/3000-plus-left-without-electricity-in-central-ontario-after-thunderstorms/}}</ref> Three tornadoes touched down across the province: one EF2 near [[Glenarm, Ontario|Glenarm]] and two EF0s.<ref name="OntarioTornado3">{{cite web|author=Nicole Mortillaro |publisher=Global News |date=May 24, 2013 |accessdate=May 25, 2013 |title=Environment Canada confirms two more tornadoes in Ontario |url=http://globalnews.ca/news/588673/environment-canada-confirms-two-more-tornadoes-in-ontario/ |url-status=live |archiveurl=https://web.archive.org/web/20130617185904/http://globalnews.ca/news/588673/environment-canada-confirms-two-more-tornadoes-in-ontario/ |archivedate=June 17, 2013 }}</ref><ref name="OntarioTornado1">{{cite web|publisher=The Weather Network|date=May 23, 2013|accessdate=May 23, 2013|title=Environment Canada confirms Ontario's second tornado of 2013|url=http://www.theweathernetwork.com/news/articles/environment-canada-confirms-ontarios-second-tornado-of-2013/6685/}}</ref><ref name="OntarioTornado2">{{cite news|publisher=[[Canadian Broadcasting Corporation]]|date=May 22, 2013|access-date=May 23, 2013|title=Tornado touches down in Ontario town|url=https://www.cbc.ca/news/canada/toronto/tornado-touches-down-in-ontario-town-1.1320361}}</ref> In New York, two [[microburst]]s, both with winds up to {{convert|70|mph|km/h|abbr=on}}, caused minor damage in [[Cayuga County, New York|Cayuga]] and [[Seneca County, New York|Seneca]] counties.<ref>{{cite web|work=National Weather Service in Binghamton, New York |publisher=National Oceanic and Atmospheric Administration |date=May 22, 2013 |accessdate=May 23, 2013 |title=Microburst /Straight Line Wind Damage/ Confirmed Near Scipio Center in Cayuga County New York |url=http://forecast.weather.gov/product.php?site%3DBGM%26issuedby%3DBGM%26product%3DPNS%26format%3Dtxt%26version%3D1%26glossary%3D0 |archive-url=https://web.archive.org/web/20081217123515/http://forecast.weather.gov/product.php?site=BGM&issuedby=BGM&product=PNS&format=txt&version=1&glossary=0 |url-status=dead |archive-date=December 17, 2008 }}</ref> Further south, a [[tornado warning]] was issued for [[Columbia County, New York|Columbia]] and [[Dutchess County, New York|Dutchess]] Counties after a trained spotter mistakenly reported a tornado on the ground near the town [[Copake, New York|Copake]]; it was later discovered that the spotter was looking at [[Scud (cloud)|scud clouds]] rather than a funnel or a tornado.<ref>{{cite web|author=Ryan Hanrahan|publisher=MSNBC|date=May 22, 2013|accessdate=May 23, 2013|title=False Weather Report Leads to Tornado Warning|url=http://www.nbcconnecticut.com/news/local/False-Weather-Report-Leads-to-Tornado-Warning-208584411.html}}{{dead link|date=August 2013}}</ref>

Throughout May 21, the SPC received a total of 413 reports of severe weather: none for tornadoes, 307 for wind, and 106 for hail.<ref name="0521rpt">{{cite web|work=Storm Prediction Center|publisher=National Oceanic and Atmospheric Administration|date=May 27, 2013|accessdate=May 27, 2013|title=20130521's Storm Reports (1200 UTC − 1159 UTC)|url=http://www.spc.noaa.gov/climo/reports/130521_rpts.html}}</ref>

===May 22–26===
In [[Putnam County, West Virginia]] a microburst with winds up to {{convert|80|mph|km/h|abbr=on}} destroyed two mobile homes and damaged five others, resulting in two injuries.<ref>{{cite web|work=National Weather Service in Charleston, West Virginia |publisher=National Oceanic and Atmospheric Administration |date=May 23, 2013 |accessdate=May 23, 2013 |title=Microburst Confirmed in Teays Valley in Putnam County West Virginia |url=http://forecast.weather.gov/product.php?site%3DNWS%26product%3DPNS%26issuedby%3DRLX |archive-url=https://web.archive.org/web/20111020042852/http://forecast.weather.gov/product.php?site=NWS&product=PNS&issuedby=RLX |url-status=dead |archive-date=October 20, 2011 }}</ref> One person was injured by {{convert|1.75|in|cm}} diameter hail, near [[Roscoe, New York]].<ref name="0522rpt"/>

Throughout May 22, the SPC received a total of 202 reports of severe weather: none for tornadoes, 145 for wind, and 57 for hail.<ref name="0522rpt">{{cite web|work=Storm Prediction Center|publisher=National Oceanic and Atmospheric Administration|date=May 27, 2013|accessdate=May 27, 2013|title=20130522's Storm Reports (1200 UTC − 1159 UTC)|url=http://www.spc.noaa.gov/climo/reports/130522_rpts.html}}</ref>

On May 23, the slow moving system reached the [[Eastern United States]], resulting in scattered thunderstorms across the region.<ref>{{cite web|author=Michael J. Vojtesak |work=Weather Prediction Center |publisher=National Oceanic and Atmospheric Administration |date=May 23, 2013 |accessdate=May 27, 2013 |title=Short Range Forecast Discussion Valid 12Z Thu May 23, 2013 – 12Z Sat May 25, 2013 |url=http://www.hpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc%3Dpmdspd%26version%3D7%26fmt%3Dreg |archive-url=https://web.archive.org/web/20111118081426/http://www.hpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdspd&version=7&fmt=reg |url-status=dead |archive-date=November 18, 2011 }}</ref> Located over the [[Ohio River Valley]] on May 24, prolonged heavy rains were expected across much of the Northeastern U.S. with unseasonably cold air following.<ref>{{cite web|author=Frank James Pereira III |work=Weather Prediction Center |publisher=National Oceanic and Atmospheric Administration |date=May 24, 2013 |accessdate=May 27, 2013 |title=Short Range Forecast Discussion Valid 12Z Fri May 24, 2013 – 12Z Sun May 26, 2013 |url=http://www.hpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc%3Dpmdspd%26version%3D5%26fmt%3Dreg |archive-url=https://web.archive.org/web/20111118081421/http://www.hpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdspd&version=5&fmt=reg |url-status=dead |archive-date=November 18, 2011 }}</ref> Later that day, a cold front extending from the trough moved offshore and over the western [[Atlantic Ocean]].<ref>{{cite web|author=David F. Hamrick |work=Weather Prediction Center |publisher=National Oceanic and Atmospheric Administration |date=May 24, 2013 |accessdate=May 27, 2013 |title=Short Range Forecast Discussion Valid 00Z Sat May 25, 2013 – 00Z Mon May 27, 2013 |url=http://www.hpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc%3Dpmdspd%26version%3D4%26fmt%3Dreg |archive-url=https://web.archive.org/web/20111118081417/http://www.hpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdspd&version=4&fmt=reg |url-status=dead |archive-date=November 18, 2011 }}</ref> Early on May 25, a closed circulation consolidated off the coast of New England and the system stalled out. Situated over the ocean, a continuous stream of Atlantic moisture was brought over the Northeast, resulting in "anomalously cold temperatures" and prolonged heavy precipitation.<ref>{{cite web|author=Frank James Pereira III |work=Weather Prediction Center |publisher=National Oceanic and Atmospheric Administration |date=May 25, 2013 |accessdate=May 27, 2013 |title=Short Range Forecast Discussion Valid 12Z Sat May 25, 2013 – 12Z Mon May 27, 2013 |url=http://www.hpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc%3Dpmdspd%26version%3D3%26fmt%3Dreg |archive-url=https://web.archive.org/web/20111118083106/http://www.hpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdspd&version=3&fmt=reg |url-status=dead |archive-date=November 18, 2011 }}</ref> During the overnight hours of May 25–26, record-late snow fell across portions of New York, [[New Hampshire]], [[Vermont]] and Ontario. Meteorologists noted the system was similar to a winter [[nor'easter]] than a spring storm.<ref name="NHSnow"/> After affecting the country for 11 days, the system moved over southeastern Canada late on May 26. This was the final mention of the cyclone by the [[Weather Prediction Center]].<ref>{{cite web|author=Marybeth Gerhardt |work=Weather Prediction Center |publisher=National Oceanic and Atmospheric Administration |date=May 26, 2013 |accessdate=May 27, 2013 |title=Short Range Forecast Discussion Valid 00Z Mon May 27, 2013 – 00Z Wed May 29, 2013 |url=http://www.hpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc%3Dpmdspd%26version%3D0%26fmt%3Dreg |archive-url=https://web.archive.org/web/20121110060418/http://www.hpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdspd&version=0&fmt=reg |url-status=dead |archive-date=November 10, 2012 }}</ref><ref>{{cite web|author=Paul Allen Ziegenfelder |work=Weather Prediction Center |publisher=National Oceanic and Atmospheric Administration |date=May 27, 2013 |accessdate=May 27, 2013 |title=Short Range Forecast Discussion Valid 12Z Mon May 27, 2013 – 12Z Wed May 29, 2013 |url=http://www.hpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdspd |url-status=dead |archiveurl=https://web.archive.org/web/20110714033922/http://www.hpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdspd |archivedate=July 14, 2011 }}</ref>

==Confirmed tornadoes==
{{See also|List of tornadoes in the tornado outbreak of May 18–21, 2013}}
{{Tornado Chart
|Total = 78
|F0 = 37
|F1 = 32
|F2 = 5
|F3 = 1
|F4 = 2
|F5 = 1
|Enhanced=yes
}}

===Lake Thunderbird–Bethel Acres–Shawnee, Oklahoma===
{{Infobox storm
| name = Lake Thunderbird–Bethel Acres–Shawnee, Oklahoma
| formed = May&nbsp;19, 2013, 6:00&nbsp;p.m.
| duration = 50 minutes
| dissipated = May&nbsp;19, 2013, 6:50&nbsp;p.m.
| image = Chriscalvert-shawneetornado.jpg
| caption = The EF4 Lake Thunderbird-Shawnee tornado.
| total fatalities = 2&nbsp;fatalities, 10&nbsp;injuries
| damages = 
| highest winds = {{convert|190|mph|km/h|abbr=on}}
| fujitascale = EF4
| enhanced = yes
}}

At 6:00&nbsp;p.m. CDT (2300 UTC) on May 19, a tornado touched down along the western shore of [[Lake Thunderbird]] in eastern Cleveland County (east of [[Norman, Oklahoma|Norman]]).<ref name="NormanMay22PNS">{{cite web|work=National Weather Service Office in Norman, Oklahoma|publisher=National Oceanic and Atmospheric Administration|date=May 22, 2013|accessdate=June 15, 2013|title=Latest on Tornado Information for May 19 and May 20|url=http://www.srh.noaa.gov/oun/?n=events-20130519-pns}}</ref> Initially, the tornado was weak, damaging roofs and trees (though a metal building was destroyed at EF2 intensity in this area).<ref name="apps.dat.noaa.gov">{{Cite web|url=https://apps.dat.noaa.gov/StormDamage/DamageViewer/|title=ArcGIS Web Application}}</ref> The tornado intensified as it crossed Lake Thunderbird, destroying a mobile home and tearing the roofs off of two frame homes as it reached the eastern shore of the lake. Further northeast, the tornado intensified further to EF3 strength as it tore through several nearby subdivisions, heavily damaging or destroying numerous homes and mobile homes, and toppling several metal high-tension truss towers. The tornado widened and weakened back to EF2 strength as it crossed S Harrah Rd, completely destroying several mobile homes and outbuildings in that area.<ref name="apps.dat.noaa.gov"/> The tornado maintained EF2 strength as it passed directly over the Shawnee Reservoir, destroying numerous mobile homes and tearing roofs off of frame homes along the shore.<ref name="apps.dat.noaa.gov"/> The tornado regained EF3 intensity as it passed northwest of [[Bethel Acres, Oklahoma|Bethel Acres]], and a [[Trailer park|mobile home park]] sustained a direct hit from the tornado in this area, with 30–35 mobile homes completely destroyed.<ref>{{cite web|title=EF4 tornado in Shawnee Sunday destroys 75 percent of Bethel Acres; survivor remained in mobile home|url=http://www.kjrh.com/dpp/news/local_news/ef4-tornado-in-shawnee-sunday-destroys-75-percent-of-bethel-acres-survivor-remained-in-mobile-home|publisher=[[KJRH-TV]]|accessdate=2013-05-24|date=2013-05-25}}</ref> There, one person was killed and six others were injured, two critically.<ref name="ShawneeDeaths"/><ref name="Oklatorn">{{cite news|author=Sean Murphy |agency=Associated Press|newspaper=The Columbus Dispatch|date=May 20, 2013|accessdate=May 20, 2013|title=Oklahoma tornadoes leave 1 dead, 20 hurt|location=Shawnee, Oklahoma|url=http://www.dispatch.com/content/stories/national_world/2013/05/20/oklahoma-tornadoes-leave-1-dead-20-hurt.html}}</ref><ref name="ABC1">{{cite web|author=Anthony Castellano|publisher=ABC News|date=May 20, 2013|accessdate=May 20, 2013|title=Tornadoes in Midwest Kill 1 With More Severe Weather Due Today|url=https://abcnews.go.com/US/tornadoes-midwest-kill-severe-weather-due-today/story?id=19214390#.UZoidOs9Gg4}}</ref> A frame home near the mobile home park was left with only interior rooms standing.<ref name="apps.dat.noaa.gov"/>

Past the mobile home park, the large stovepipe tornado intensified further into a violent EF4. A permanent home in this area was swept completely away with only the slab foundation remaining and much of the debris blown to the northeast. Several trees were denuded and debarked in this area, one of which was found with a truck wrapped around it.<ref name="apps.dat.noaa.gov"/><ref name="ncdc.noaa.gov">{{Cite web|url=http://www.ncdc.noaa.gov/stormevents/eventdetails.jsp?id=451506|title=Storm Events Database - Event Details &#124; National Centers for Environmental Information}}</ref> The tornado continued across a nearby open field, leaving behind a pronounced swath of ground scouring.<ref name="apps.dat.noaa.gov"/> The tornado then weakened back to EF2 strength as it crossed [[Interstate 40]] at exit 181 ([[U.S. Route 177|U.S. Highway 177]]) at the northwest edge of [[Shawnee, Oklahoma|Shawnee]]. There, a [[tractor-trailer]] was blown off an overpass (falling {{convert|20|ft|m}}) and destroyed, while two other trucks were knocked over on their sides. The driver of the first truck sustained minor injuries. Several smaller vehicles were impacted as well, resulting in a fatality and several injuries.<ref name="ncdc.noaa.gov"/><ref>{{cite news|author=Jaclyn Cosgrove|newspaper=The Oklahoman|date=May 20, 2013|accessdate=May 20, 2013|title= Oklahoma tornadoes: Tractor-trailers thrown about on Interstate 40 |url=http://newsok.com/oklahoma-tornadoes-tractor-trailers-thrown-about-on-interstate-40/article/3827132}}</ref> The incident shut down U.S. 177 and westbound lanes of Interstate 40 in the area; U.S. 177 reopened the following morning, while traffic on the interstate was restricted to one lane.<ref>{{cite web|agency=Associated Press|publisher=NewsOn9|date=May 20, 2013|accessdate=May 20, 2013|title=Lanes reopening near Shawnee but delays expected|url=http://www.news9.com/story/22296332/lanes-reopening-near-shawnee-but-delays-expected|location=Shawnee, Oklahoma}}{{dead link|date=August 2013}}</ref> A mobile home and several outbuildings were destroyed in this area, and a permanent home had its roof torn off.<ref name="apps.dat.noaa.gov"/> Turning sharply to the north, a final brief area of EF3 damage was noted as a home was left with only interior walls standing, and several other nearby homes were damaged to a lesser degree. Further to the northeast, the tornado tore the roof off of a house and destroyed two outbuildings at EF2 strength. The tornado later dissipated at 6:50&nbsp;p.m. CDT (2350 UTC) about {{convert|6.5|mi|km}} southeast of [[McLoud, Oklahoma|McLoud]], after causing some additional minor tree damage along Coker Rd.<ref name="apps.dat.noaa.gov"/> During its 50-minute track, the tornado attained EF4 intensity and remained on the ground for approximately {{convert|20|mi|km}}.<ref name="NormanMay22PNS"/> Debris from the tornado was reported to have fallen in [[Bristow, Oklahoma|Bristow]], [[Depew, Oklahoma|Depew]] and [[Tulsa, Oklahoma|Tulsa]].<ref name="DebrisFall">{{cite web|publisher=NewsOn6|date=May 20, 2013|accessdate=May 20, 2013|title=Carney Debris Falls In Hallett; Tornado Touches Down Near Prague|location=Carney, Oklahoma|url=http://www.newson6.com/story/22293813/storms-move-into-tulsa-metro-area}}</ref>



===Moore, Oklahoma===
{{Infobox weather event
| name = Moore, Oklahoma
| formed = May&nbsp;20, 2013, 2:56&nbsp;p.m. [[Central Daylight Time|CDT]] ([[UTC−05:00]])
| duration = 39 minutes
| dissipated = May&nbsp;20, 2013, 3:35&nbsp;p.m. CDT (UTC−05:00)
| image = FEMA Aerial view of May 20, 2013 Moore, Oklahoma tornado damage.jpg
| caption = Aerial view of catastrophic damage to the Plaza Towers neighborhood in Moore.
}}{{Infobox weather event/Tornado
| winds = {{convert|210|mph|km/h|abbr=on}}
| fujita-scale = EF5
}}{{Infobox weather event/Effects
| fatalities = 24
| injuries = 212
}}{{Infobox weather event/Footer
}}
{{Main|2013 Moore tornado}}
During the early afternoon of May 20, severe thunderstorms quickly developed across much of central Oklahoma. At 2:40&nbsp;p.m. CDT (1940 UTC), a tornado warning was issued for a storm approaching the Oklahoma City metropolitan area.<ref name="FirstTornadoWarning">{{cite web|work=National Weather Service Office in Norman Oklahoma|publisher=Iowa Environmental Mesonet|date=May 20, 2013|accessdate=May 21, 2013|title=Bulletin: Tornado Warning|url=http://mesonet.agron.iastate.edu/wx/afos/p.php?pil=TOROUN&e=201305201940}}</ref> Sixteen minutes later, a tornado touched down roughly {{convert|3|mi|km}} northwest of the center of [[Newcastle, Oklahoma|Newcastle]] in [[McClain County, Oklahoma|McClain County]]. Tracking northeast, the system rapidly intensified, attaining EF4 intensity within seconds of touching down. After crossing the [[Interstate 44]] bridge over the [[Canadian River]], the tornado turned east and tracked directly through [[Oklahoma City|South Oklahoma City]] and [[Moore, Oklahoma|Moore]], producing a large swath of catastrophic damage through densely populated areas. Numerous homes sustained EF4 damage in the Moore, and a few scattered instances of EF5 damage were also noted.<ref name="NormanSurvey">{{cite web|work=National Weather Service Office in Norman Oklahoma|publisher=Iowa Environmental Mesonet|date=May 21, 2013|accessdate=May 23, 2013|title=NWS Damage Survey for 5/20/2013 Newcastle/Moore Tornado Event – Update 3|url=http://mesonet.agron.iastate.edu/wx/afos/p.php?pil=PNSOUN&e=201305211950}}</ref> Based on multiple instances of well-built, anchor-bolted brick homes being completely swept away in Moore, along with the presence of severe ground scouring, wind-rowing of structural debris, and large multi-ton objects being lofted long distances through the air, it was estimated that the tornado had peak winds of {{convert|210|mph|km/h|abbr=on}}.<ref name="NWSNormanMay20">{{cite web|work=National Weather Service Office in Norman, Oklahoma|publisher=National Oceanic and Atmospheric Administration|date=May 24, 2013|accessdate=May 24, 2013|title=The Tornado Outbreak of May 20, 2013|url=http://www.srh.noaa.gov/oun/?n=events-20130520}}</ref> The storm abruptly dissipated at 3:35&nbsp;p.m. CDT (2035 UTC) about {{convert|4.8|mi|km}} east of Moore.<ref name="NormanSurvey"/>

Taking a path through the heart of Moore, an estimated 13,500 people were directly affected by the tornado.<ref>{{cite web|work=National Weather Service Office in Norman, Oklahoma |publisher=National Oceanic and Atmospheric Administration |date=May 23, 2013 |accessdate=May 24, 2013 |title=May 20, 2013 EF-5 Tornado Path and LandScan Population |type=Image |format=.jpg |url=http://www.srh.noaa.gov/images/fxc/oun/graphicast/image_full8.jpg |url-status=live |archiveurl=https://web.archive.org/web/20111016070622/http://www.srh.noaa.gov/images/fxc/oun/graphicast/image_full8.jpg |archivedate=October 16, 2011 }}</ref> Large swaths of the city were completely destroyed and unofficial estimates placed the number of severely damaged or destroyed buildings at 1,500 with another 4,000 affected.<ref name="NYT2">{{cite news|newspaper=The New York Times|date=May 21, 2013|accessdate=May 22, 2013|title=Assessing the Damage Along the Tornado's Path in Oklahoma|url=https://www.nytimes.com/interactive/2013/05/20/us/oklahoma-tornado-map.html?_r=1&}}</ref> In contrast to the violent nature of the tornado, the death toll was relatively low. A total of 24 people lost their lives, nine of whom were children, and over 200 were injured.<ref name="ReutersMay22"/> This ranks it as the ninth-deadliest tornado in the state's history.<ref>{{cite web|work=National Weather Service Office in Norman, Oklahoma|publisher=National Oceanic and Atmospheric Administration|date=January 12, 2013|accessdate=May 21, 2013|title=Top Ten Deadliest Oklahoma Tornadoes (1882–Present)|url=http://www.srh.noaa.gov/oun/?n=tornadodata-ok-deadliest}}</ref> The lack of further fatalities was attributed to a 16-minute lead time on the Moore tornado given by the [[National Weather Service Norman, Oklahoma|National Weather Service forecast office in Norman]].<ref name="ReutersMay22">{{cite news|author1=Carey Gillam |author2=Ian Simpson |name-list-style=amp |work=Reuters |date=May 22, 2013 |accessdate=May 24, 2013 |title=Oklahoma tornado victims astounded at how they survived |url=https://www.reuters.com/article/us-usa-tornadoes-idUSBRE94J0TK20130523 |location=Moore, Oklahoma |url-status=live |archiveurl=https://web.archive.org/web/20130524173912/http://www.reuters.com/article/2013/05/23/us-usa-tornadoes-idUSBRE94J0TK20130523 |archivedate=May 24, 2013 }}</ref> Risk Management Solutions Inc. estimated that the insurance payout from the tornado would amount to $2–3.5 billion, stating that the event was worse than the [[1999 Bridge Creek–Moore tornado]] and may rival the [[2011 Joplin tornado]].<ref>{{cite news|author=Eleazar David Melendez|work=Huffington Post|date=May 21, 2013|accessdate=May 24, 2013|title= Moore Tornado Costs Could Total $3 Billion |url=http://www.huffingtonpost.com/2013/05/21/moore-tornado-costs-total_n_3314102.html}}</ref><ref>{{cite web|author=Noah Buhayar|work=Bloomberg Business News|publisher=Insurance Journal|date=May 29, 2013|accessdate=May 30, 2013|title=Oklahoma Tornado Cost Insurers as Much as $3.5 Billion: RMS|url=http://www.insurancejournal.com/news/national/2013/05/29/293533.htm}}</ref>
{{clear}}

==Non-tornadic events==
[[File:May 23, 2013 flood damage in Jericho, Vermont.png|thumb|Damage from flash flooding in [[Jericho, Vermont]] on May 23.]]
Alongside the destructive tornadoes, prolonged heavy rains affected much of the Southern and Central United States.<ref name="MSSoE"/> The heaviest rains fell across parts of [[North Dakota]], with accumulations amounting to {{convert|9.5|in|mm}} near [[Milton, North Dakota|Milton]] in [[Cavalier County, North Dakota|Cavalier County]] over a three-day span.<ref name="NWSGrandForks">{{cite web|work=National Weather Service Office in Grand Forks, North Dakota |publisher=National Oceanic and Atmospheric Administration |date=May 21, 2013 |accessdate=May 24, 2013 |title=Public Information Statement: All 3 Day Storm Totals |url=http://www.nws.noaa.gov/view/validProds.php?prod%3DPNS%26node%3DKFGF |archive-url=https://web.archive.org/web/20120406095623/http://www.nws.noaa.gov/view/validProds.php?prod=PNS&node=KFGF |url-status=dead |archive-date=April 6, 2012 }}</ref> On May 19, many areas in the state recorded daily record rains with [[Bismarck, North Dakota|Bismarck]] receiving {{convert|1.45|in|mm|abbr=on}}, surpassing the record set in 1877.<ref>{{cite web|work=National Weather Service Office in Bismarck, North Dakota |publisher=National Oceanic and Atmospheric Administration |date=May 19, 2013 |accessdate=May 24, 2013 |title=Record Event Report: Record Daily Maximum Rainfall Set At Bismarck ND |url=http://forecast.weather.gov/product.php?site%3DBIS%26issuedby%3DBIS%26product%3DRER%26format%3DCI%26version%3D3%26glossary%3D0 |archive-url=https://web.archive.org/web/20201019114108/https://forecast.weather.gov/product.php?site=BIS&issuedby=BIS&product=RER&format=CI&version=3&glossary=0 |url-status=dead |archive-date=October 19, 2020 }}</ref> On May 21, concerns arose that the [[Renwick Dam]] along the [[Tongue River (North Dakota)|Tongue River]] could collapse. Roughly 1,300 people in the town of [[Cavalier, North Dakota|Cavalier]] were urged to evacuate. [[North Dakota Highway 18|Highway 18]] and [[North Dakota Highway 5|Highway 5]] in the area were closed due to flooding.<ref name="NDFlood1"/> In nearby [[Crystal, North Dakota|Crystal]], half of the town was flooded despite efforts to protect it with 8,000 sandbags.<ref>{{cite web|agency=Associated Press |publisher=Insurance Journal |date=May 22, 2013 |accessdate=May 24, 2013 |title=Record Rain Leading to Flooding in North Dakota |url=http://www.insurancejournal.com/news/midwest/2013/05/22/292965.htm |url-status=live |archiveurl=https://web.archive.org/web/20130621072806/http://www.insurancejournal.com/news/midwest/2013/05/22/292965.htm |archivedate=June 21, 2013 }}</ref> With fears of the dam collapse in North Dakota, the [[Army National Guard|National Guard]] was deployed to Cavalier in order to construct emergency [[levee]]s.<ref name="NDFlood1">{{cite news|author1=Blake Nicholson  |author2=Dave Kolpack  |name-list-style=amp |agency=Associated Press |publisher=News 9 |date=May 22, 2013 |accessdate=May 23, 2013 |title=Flooding forces evacuation of 1,300 in ND town |location=Bismarck, North Dakota |url=http://www.news9.com/story/22397692/flooding-forces-evacuation-of-1300-in-nd-town }}{{dead link|date=June 2016|bot=medic}}{{cbignore|bot=medic}}</ref> Early on May 23, the water level at the dam began receding and fears of it collapsing subsided.<ref>{{cite news|agency=Associated Press|newspaper=The Washington Post|date=May 23, 2013|accessdate=May 23, 2013|title=Dam failure risk near NE North Dakota city may be easing; city mulls return of 1,300 evacuees|url=http://www.foxnews.com/weather/2013/05/23/dam-failure-risk-near-ne-north-dakota-city-may-be-easing-city-mulls-return-1300/|archive-url=https://web.archive.org/web/20130524023911/http://www.foxnews.com/weather/2013/05/23/dam-failure-risk-near-ne-north-dakota-city-may-be-easing-city-mulls-return-1300/|url-status=dead|archive-date=May 24, 2013|location=Bismarck, North Dakota}}</ref>

Similarly heavy, though not as extreme, rains fell in Minnesota. There, accumulations peaked near [[Osage, Minnesota|Osage]] in [[Becker County, Minnesota|Becker County]] at {{convert|4.55|in|mm|abbr=on}}.<ref name="NWSGrandForks"/> On May 22, a landslide at [[Mississippi National River and Recreation Area|Lilydale Regional Park]] killed two children and injured two others on a field trip.<ref name="MNDeaths">{{cite web|author=Matthew DeLuca |publisher=NBC News |date=May 23, 2013 |accessdate=May 24, 2013 |title=Two children killed in Minnesota field trip landslide |url=http://usnews.nbcnews.com/_news/2013/05/23/18441754-two-children-killed-in-minnesota-field-trip-landslide?lite |url-status=live |archiveurl=https://web.archive.org/web/20130608113224/http://usnews.nbcnews.com/_news/2013/05/23/18441754-two-children-killed-in-minnesota-field-trip-landslide?lite |archivedate=June 8, 2013 }}</ref> Elsewhere in the country, heavy rain events lead to numerous instances of localized flash flooding. Notable flooding occurred in the [[New York metropolitan area|New York City metropolitan area]],<ref>{{cite news|author=Ken Schachter |newspaper=Newsday |date=May 23, 2013 |accessdate=May 24, 2013 |title=Flash flood warning remains in Westchester; Taconic, Saw Mill River partly closed |url=http://newyork.newsday.com/news/weather/flash-flood-warning-remains-in-westchester-taconic-saw-mill-river-partly-closed-1.5322256?qr=1 |url-status=dead |archiveurl=https://archive.today/20240522201106/https://www.webcitation.org/6Gr8zcuP5?url=http://newyork.newsday.com/news/weather/flash-flood-warning-remains-in-westchester-taconic-saw-mill-river-partly-closed-1.5322256%3Fqr=1 |archivedate=May 22, 2024 }}</ref><ref>{{cite web|publisher=WNBC4 New York |date=May 24, 2013 |accessdate=May 24, 2013 |title=Flash Flood Warnings as Storms Move Through Tri-State |url=http://www.nbcnewyork.com/news/local/Thunderstorm-Rain-Weather-Forecast-New-York-New-Jersey-Connecticut-208625151.html |url-status=live |archiveurl=https://web.archive.org/web/20130810102010/http://www.nbcnewyork.com/news/local/Thunderstorm-Rain-Weather-Forecast-New-York-New-Jersey-Connecticut-208625151.html |archivedate=August 10, 2013 }}</ref> [[Memphis, Tennessee]],<ref>{{cite web|publisher=WMC-TV 5|date=May 21, 2013|accessdate=May 23, 2013|title=Cars stuck in water covered roadways|url=http://www.wmctv.com/story/22379186/cars-stuck-in-water-covered-roadways}}</ref> and [[Southaven, Mississippi]].<ref name="CAMay21">{{cite news|author1=Yolanda Jones |author2=Michael Lollar |author3=Ron Maxey |newspaper=Commercial Appeal|date=May 21, 2013|accessdate=May 23, 2013|title=Flooding prompts Southaven mayor to declare emergency; some Memphis streets also under water|url=http://www.commercialappeal.com/news/2013/may/21/flooding-prompts-southaven-mayor-to-declare/}}</ref> The latter of these areas declared a state of emergency as a result of the storms.<ref name="MSSoE">{{cite web|author=Michael Clark|publisher=Southaven Horn-Lake|date=May 22, 2013|accessdate=May 23, 2013|title=Southaven declares state of emergency after flooding|url=http://southaven-hornlake.wmctv.com/news/news/138292-southaven-declares-state-emergency-after-flooding|archive-url=https://archive.today/20130630172433/http://southaven-hornlake.wmctv.com/news/news/138292-southaven-declares-state-emergency-after-flooding|url-status=dead|archive-date=June 30, 2013}}</ref> Further northeast, record rains triggered damaging floods in Vermont.<ref>{{cite web|author=Jack Thurston |publisher=New England Cable News |date=May 23, 2013 |accessdate=May 26, 2013 |title=Vt. city cleans up from damaging flash floods |url=http://www.necn.com/05/23/13/Vt-city-cleans-up-from-damaging-flash-fl/landing.html?blockID%3D841895%26feedID%3D11106 |archive-url=https://archive.today/20240522201225/https://www.webcitation.org/6GuQelxxV?url=http://www.necn.com/05/23/13/Vt-city-cleans-up-from-damaging-flash-fl/landing.html%3FblockID=841895&feedID=11106 |url-status=dead |archive-date=May 22, 2024 |location=Burlington, Vermont }}</ref> Many areas received over {{convert|3|in|abbr=on}} of rain, with a maximum of {{convert|6.79|in|mm|abbr=on}} falling in [[Jeffersonville, Vermont|Jeffersonville]].<ref>{{cite web|work=National Weather Service in Burlington, Vermont |publisher=National Oceanic and Atmospheric Administration |date=May 24, 2013 |accessdate=May 26, 2013 |title=Public Information Statement: Storm Total Rainfall |url=http://forecast.weather.gov/product.php?site%3DBTV%26issuedby%3DBTV%26product%3DPNS%26format%3DCI%26version%3D8%26glossary%3D0 |archive-url=https://web.archive.org/web/20120210034234/http://forecast.weather.gov/product.php?site=BTV&issuedby=BTV&product=PNS&format=CI&version=8&glossary=0 |url-status=dead |archive-date=February 10, 2012 }}</ref> Several homes were damaged, one beyond repair, roads were washed out, and bridges were damaged. Several [[culvert]]s, already known to be inadequate following flooding from [[Hurricane Irene|Tropical Storm Irene]] in 2011, were overwhelmed.<ref name="VTFlood">{{cite news|author=Wilson Ring |agency=Associated Press |newspaper=San Francisco Chronicle |date=May 24, 2013 |accessdate=May 26, 2013 |title=Vt. seeks US damage assessment after flash floods |url=http://www.sfgate.com/news/article/Vt-seeks-US-damage-assessment-after-flash-floods-4545611.php |location=Underhill, Vermont |url-status=live |archiveurl=https://archive.today/20240522201305/https://www.webcitation.org/6GuRShCSB?url=http://www.sfgate.com/news/article/Vt-seeks-US-damage-assessment-after-flash-floods-4545611.php |archivedate=May 22, 2024 }}</ref> Damage in [[Underhill, Vermont|Underhill]] was estimated at $1.7–2.3 million.<ref>{{cite web|author=Matt Ryan|publisher=Burlington Free-Press|date=May 29, 2013|accessdate=June 15, 2013|title=Storm damage in Underhill could exceed $2 million|url=http://www.burlingtonfreepress.com/article/20130529/NEWS02/305290007/FEMA-teams-in-Vermont-to-assess-flash-flood-damage|location=Underhill, Vermont}}</ref>

Between May 25 and 26, unusually late snowfall impacted parts of Vermont, New Hampshire and Ontario. Most accumulations were limited to higher elevations; however, in parts of New Hampshire, snow levels fell to {{convert|500|ft|m|abbr=on}} in altitude.<ref name="NHSnow"/> Notable measurements in the state included {{convert|4|in|cm|abbr=on}} in [[Jefferson, New Hampshire|Jefferson]] and {{convert|2|in|cm|abbr=on}} in [[Alexandria, New Hampshire|Alexandria]].<ref>{{cite web|work=National Weather Service Office in Grey, Maine |publisher=National Oceanic and Atmospheric Administration |date=May 26, 2013 |accessdate=May 26, 2013 |title=Public Information Statement: Storm Total Snowfall |url=http://forecast.weather.gov/product.php?site%3Dgyx%26product%3Dpns%26issuedby%3DGYX%26format%3DCI%26version%3D1%26glossary%3D0 |archive-url=https://web.archive.org/web/20220615101004/https://forecast.weather.gov/product.php?site=gyx&product=pns&issuedby=GYX&format=CI&version=1&glossary=0 |url-status=dead |archive-date=June 15, 2022 }}</ref> These accumulations tied the record-latest snowfall date in New Hampshire of May 26, 1967.<ref name="NHSnow">{{cite news|author=Bill Smith |newspaper=New Hampshire Union Leader |date=May 26, 2013 |accessdate=May 26, 2013 |title=Late snowfall ties New Hampshire record set in 1967 |url=http://www.unionleader.com/article/20130526/NEWS11/130529380 |location=Manchester, New Hampshire |url-status=live |archiveurl=https://web.archive.org/web/20160915191135/http://www.unionleader.com/article/20130526/NEWS11/130529380 |archivedate=September 15, 2016 }}</ref> Snowfall was expected to reach {{convert|6|in|cm|abbr=on}} in the eastern townships of Ontario.<ref>{{cite web|work=Québecor Média |publisher=Sun News |date=May 26, 2013 |accessdate=May 26, 2013 |title=Snow falls on Quebec's Eastern Townships |url=http://www.sunnewsnetwork.ca/sunnews/canada/archives/2013/05/20130526-090812.html |location=Montreal, Canada |url-status=live |archiveurl=https://web.archive.org/web/20130529162643/http://www.sunnewsnetwork.ca/sunnews/canada/archives/2013/05/20130526-090812.html |archivedate=May 29, 2013 }}</ref> The combination of heavy rains and snow in Vermont led to significant power outages in the state, with Green Mountain Power reporting approximately 12,100 residences without electricity.<ref>{{cite web|agency=Associated Press |publisher=New England Cable News |date=May 26, 2013 |accessdate=May 26, 2013 |title=Snow, rain pound Vermont |url=http://www.necn.com/05/26/13/Snow-rain-pound-Vermont/landing.html?%26apID%3D2770eef3753e4bcb8fe6d53b393a3817 |archive-url=https://archive.today/20240522201147/https://www.webcitation.org/6GuQArjtj?url=http://www.necn.com/05/26/13/Snow-rain-pound-Vermont/landing.html%3F&apID=2770eef3753e4bcb8fe6d53b393a3817 |url-status=dead |archive-date=May 22, 2024 |location=Burlington, Vermont }}</ref> Some areas in the state received over {{convert|6|in|cm|abbr=on}} of snow, with a maximum of {{convert|13.2|in|cm|abbr=on}} falling on [[Mount Mansfield]].<ref>{{cite web|work=National Weather Service Office in Burlington, Vermont |publisher=National Oceanic and Atmospheric Administration |date=May 27, 2013 |accessdate=May 27, 2013 |title=Public Information Statement: Storm Total Snowfall |url=http://forecast.weather.gov/product.php?site%3Dbtv%26product%3Dpns%26issuedby%3DBTV%26format%3DCI%26version%3D1%26glossary%3D0 |archive-url=https://web.archive.org/web/20220610032903/https://forecast.weather.gov/product.php?site=btv&product=pns&issuedby=BTV&format=CI&version=1&glossary=0 |url-status=dead |archive-date=June 10, 2022 }}</ref> This marked the latest {{convert|12|in|cm|abbr=on}} snowfall on record for the area.<ref>{{cite web|agency=Associated Press|publisher=Fox News|date=May 26, 2013|accessdate=May 27, 2013|title=Memorial Day weekend storm dumps up to 3 feet of snow on New York, Vermont ski mountains|url=http://www.foxnews.com/weather/2013/05/26/memorial-day-weekend-storm-dumps-up-to-3-feet-snow-on-new-york-vermont-ski/|archive-url=https://web.archive.org/web/20130527115759/http://www.foxnews.com/weather/2013/05/26/memorial-day-weekend-storm-dumps-up-to-3-feet-snow-on-new-york-vermont-ski/|url-status=dead|archive-date=May 27, 2013}}</ref> Record-late snows also occurred in [[Syracuse, New York|Syracuse]] and [[Binghamton, New York|Binghamton]], [[New York (state)|New York]].<ref>{{cite web|author=Molly Cochran|publisher=Accuweather|date=May 27, 2013|accessdate=May 27, 2013|title=Photos: Snow for Memorial Day Weekend in Parts of New England|url=http://www.accuweather.com/en/weather-news/snow-for-memorial-day-weekend/13335569}}</ref> Unofficial reports from [[Whiteface Mountain]] in the [[Adirondack Mountains|Adirondacks]] indicated as much as {{convert|34|in|cm|abbr=on}} of snow.<ref>{{cite news|newspaper=[[Daily Gazette]]|date=May 26, 2013|accessdate=May 27, 2013|title=Snowfall of 34 inches reported on Whiteface|url=https://dailygazette.com/article/2013/05/26/0527_snow}}</ref>

==Aftermath==
[[File:May 20, 2013 Moore, Oklahoma tornado search and rescue.jpg|thumb|Search and rescue operations took place throughout Moore, Oklahoma in the wake of the tornado.]]
Immediately following the May 19 tornadoes, the [[American Red Cross|Red Cross]] set up emergency shelters in [[Carney, Oklahoma|Carney]] and Shawnee to house those left homeless.<ref>{{cite news|author=Kim Morava|newspaper=News-Star|date=May 20, 2013|accessdate=May 20, 2013|title=Red Cross sets up shelter at Shawnee High School|url=http://www.news-star.com/article/20130520/NEWS/130529997}}</ref> On May 20, [[Governor of Oklahoma|Oklahoma governor]] [[Mary Fallin]] declared a [[state of emergency]] for 16 counties.<ref name="ABC1"/> The following day, [[Federal government of the United States#President|President]] [[Barack Obama]] signed a [[Disaster area|major disaster declaration]] for Cleveland, [[Lincoln County, Oklahoma|Lincoln]], [[McClain County, Oklahoma|McClain]], [[Oklahoma County, Oklahoma|Oklahoma]] and Pottawatomie counties.<ref>{{Cite news |date=2013-05-21 |title=Obama Promises Oklahoma Will Get All Aid Needed ‘Right Away’ |url=https://www.bloomberg.com/news/articles/2013-05-21/obama-promises-oklahoma-will-get-all-aid-needed-right-away- |access-date=2024-07-16 |work=Bloomberg.com |language=en}}</ref><ref>{{Cite web |date=2013-05-21 |title=Obama Signs Oklahoma Disaster Declaration |url=https://www.huffpost.com/entry/obama-oklahoma-disaster-declaration_n_3310234 |access-date=2024-07-16 |website=HuffPost |language=en}}</ref> This allowed for federal aid to be sent to residents in the hardest-hit areas of Oklahoma and gain access to temporary housing, home repairs, and low-cost loans.<ref>{{cite news|agency=Associated Press|work=The Huffington Post|date=May 21, 2013|accessdate=May 21, 2013|title= Obama Signs Oklahoma Disaster Declaration |url=http://www.huffingtonpost.com/2013/05/21/obama-oklahoma-disaster-declaration_n_3310234.html|location=Washington D.C.}}</ref> Non-governmental donations to the state reached $24 million on May 27, with $15 million coming from the Red Cross. [[Chesapeake Energy]] also provided oil-drilling equipment to be used for debris removal.<ref>{{cite web|work=CNN|publisher=[[KETK-TV]]|date=May 27, 2013|accessdate=May 27, 2013|title=Donations for Oklahoma top $20 million |url=http://www.ketknbc.com/news/donations-for-oklahoma-top-20-million-1|location=New York, United States}}</ref> The previous disaster declaration was later expanded to include areas affected by [[Tornado outbreak of May 26–31, 2013|another destructive severe weather event]] that occurred just over a week later.<ref>{{cite web|work=Federal Emergency Management Agency|publisher=Government of the United States|date=June 12, 2013|accessdate=June 15, 2013|title=Disaster Assistance Expands to Include More Storms and Canadian County|url=http://www.fema.gov/news-release/2013/06/12/disaster-assistance-expands-include-more-storms-and-canadian-county|location=Oklahoma City, Oklahoma}}</ref> Federal and state aid to Oklahoma reached $7.6 million on June 15, with more than 10,000 households applying for assistance.<ref>{{cite web|work=Federal Emergency Management Agency|publisher=Government of the United States|date=June 15, 2013|accessdate=June 15, 2013|title=Disaster Assistance Tops $7.6 Million for May 18 – June 2 Storms in Oklahoma|url=http://www.fema.gov/news-release/2013/06/14/disaster-assistance-tops-76-million-may-18-june-2-storms-oklahoma|location=Oklahoma City, Oklahoma}}</ref>

In Shawnee, the Southern Baptist Disaster Relief, the [[Salvation Army]], and Red Cross provided free meals to first responders and displaced residents. The [[Federal Emergency Management Agency]] (FEMA) set up two disaster centers: one in Shawnee and the other in Moore.<ref name="NO6May22">{{cite web|author1=Craig Day  |author2=Brandi Ball |name-list-style=amp |publisher=NewsOn6|date=May 22, 2013|accessdate=May 23, 2013|title=Shawnee Tornado Victims Begin To Pick Up Pieces|url=http://www.newson6.com/story/22399727/shawnee-tornado-victims-begin-to-pick-up-the-pieces}}</ref> In the wake of the Moore tornado, there were rumors that relief organizations were relocated from communities in Shawnee; however, the Salvation Army and local news agencies confirmed that residents in the area were getting proper assistance.<ref name="NO6May22"/>

On May 24, [[Governor of Vermont|Vermont Governor]] [[Peter Shumlin]] requested that FEMA assess the damage from floods to see if the state qualified for disaster aid.<ref name="VTFlood"/> Following the assessments, [[Chittenden County, Vermont|Chittenden]], [[Essex County, Vermont|Essex]], and [[Lamoille County, Vermont|Lamoille]] Counties were declared major disaster areas on June 13, allowed residents to receive federal aid.<ref>{{cite web|work=Federal Emergency Management Agency|publisher=Government of the United States|date=June 13, 2013|accessdate=June 15, 2013|title=President Declares Disaster for Vermont|location=Washington D.C., United States|url=http://www.fema.gov/news-release/2013/06/13/president-declares-disaster-vermont}}</ref>
{{clear}}

==See also==
{{geoGroup}}
*[[List of North American tornadoes and tornado outbreaks]]
*[[1999 Oklahoma tornado outbreak]] – an outbreak that also produced a very destructive tornado in similar areas
*[[Tornado outbreak of May 26–31, 2013]] – a similar outbreak that occurred a few days later

==Notes==
{{Reflist|group=nb}}

==References==
{{Reflist|30em}}

==External links==
{{Commons category}}
*[https://www.youtube.com/watch?v=77jiaIn4BoY Video (03:22) – "Inside" The Tornado – Moore, Oklahoma (May 20, 2013).]
*[https://www.youtube.com/watch?v=xTpceWd8UE4 Video (03:11) – "Outside" The Tornado – Moore, Oklahoma (May 20, 2013).]

{{2013 tornado outbreaks}}

{{DEFAULTSORT:2013-05-21 Tornado Outbreak}}
[[Category:Tornadoes of 2013|05-21]]
[[Category:Tornadoes in Kansas]]
[[Category:Tornadoes in Oklahoma]]
[[Category:Tornadoes in Nebraska]]
[[Category:Tornadoes in Iowa]]
[[Category:Tornadoes in Illinois]]
[[Category:Tornadoes in Missouri]]
[[Category:F5 tornadoes]]
[[Category:May 2013 events in the United States|Tornado Outbreak, 21]]
[[Category:2013 natural disasters in the United States|Tornado Outbreak, 05-21]]