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Cyclone Keli

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Severe Tropical Cyclone Keli
Category 3 severe tropical cyclone (Aus scale)
Category 4 tropical cyclone (SSHWS)
Cyclone Keli at peak intensity.
FormedJune 07, 1997
DissipatedJune 17, 1997
Highest winds10-minute sustained: 150 km/h (90 mph)
1-minute sustained: 215 km/h (130 mph)
Lowest pressure955 hPa (mbar); 28.2 inHg
FatalitiesNone reported
Damage$10,000 (1997 USD)
Areas affectedTokelau, Tuvalu, Fiji
Part of the 1996–97 South Pacific cyclone season,

Severe Tropical Cyclone Keli (NPMOC/JTWC Designation: 38P) was the first recorded post-season tropical cyclone to form in June within the South Pacific Ocean.[1][2] The system formed on June 7, 1997, about 460 kilometers (285 mi) to the north of Tokelau. The depression gradually developed over the next few days while moving southwestward. It was designated as Tropical Cyclone Keli early the next day. Cyclone Keli intensified, slowly reaching its 10-minute peak windspeeds of 150 km/h, (90 mph), which made it a Category 3 severe tropical cyclone on the Australian Tropical Cyclone Intensity Scale. As it came under the influence of strong mid latitude westerlies and moved into an area of strong vertical wind shear, the cyclone started to weaken and was declared as extratropical on June 15.

Cyclone Keli struck the islands of Tuvalu on June 12 and 13, with extensive damage reported throughout the Islands with trees uprooted by wind and waves. On Nivalakita all buildings except for the church were flattened; an estimated cost to rebuild the houses as they were was AU$12,000 (US$10,000 1997), while it was estimated that the cost of rebuilding the houses with an improved, cyclone-resistant design would be about AU$84,000 (63,000 USD 1997). The whole of Tepuka Savilivili was left uninhabitable, as coconut trees and other vegetation were swept away with no more than an area of jagged coral left behind. In Fiji, strong winds and rough seas were reported from the cyclone as it was moving to the north of Fiji, and while the cyclone was weakening it dropped 3.76 inches (95.5mm) of rain on American Somoa.

Meterological history

Map plotting the storm's track and intensity, according to the Saffir–Simpson scale
Map key
Saffir–Simpson scale
  Tropical depression (≤38 mph, ≤62 km/h)
  Tropical storm (39–73 mph, 63–118 km/h)
  Category 1 (74–95 mph, 119–153 km/h)
  Category 2 (96–110 mph, 154–177 km/h)
  Category 3 (111–129 mph, 178–208 km/h)
  Category 4 (130–156 mph, 209–251 km/h)
  Category 5 (≥157 mph, ≥252 km/h)
  Unknown
Storm type
triangle Extratropical cyclone, remnant low, tropical disturbance, or monsoon depression

Early on June 7, the Regional Specialized Meteorological Center (RSMC) in Nadi, Fiji reported that a tropical depression had formed about 460 kilometers (285 mi) to the north of Tokelau.[3] Over the next couple of days the depression moved to the southwest and gradually developed, with a tropical cyclone formation alert being issued early on June 9 by the Naval Pacific Meteorology and Oceanography Center (NPMOC), with the depression expected to intensify into a tropical cyclone within 24 hours.[3][4] Early on June 10, both RSMC Nadi and the NPMOC reported that the depression had intensified into a tropical cyclone.[4][3] RSMC Nadi assigned the name Keli to the cyclone while it was located about 1210 km (750 mi) to the northeast of Nadi.[3] At the same time the NPMOC assigned the designation of 38P to the Cyclone with wind speeds that were equivalent to a tropical storm.[4] Later that day RSMC Nadi reported that the cyclone had intensified further and had become a Category 2 tropical cyclone on the Australian tropical cyclone intensity scale.[3]

Early on June 11 as Keli crossed the International Dateline; the NPMOC reported that the organisation and outflow of Keli was good and that they were expecting the cyclone to intensify slowly before affecting Tuvalu.[4] They then passed warning responsibility of Keli to the Joint Typhoon Warning Center (JTWC) later that day. As the JTWC started to issue warnings they reported that the cyclone had intensified into a Category one tropical cyclone on the Saffir–Simpson Hurricane Scale (SSHS) while RSMC Nadi reported that it had become a Category 3 severe tropical cyclone as the cyclone started to move around Tuvalu.[4][3] As it moved around Tuvalu a mid level trough was forecast to approach the system from the west and push Keli to the south.[4] RSMC Nadi then reported early the next day that Keli had recrossed the dateline and had reached its 10-minute peak windspeeds of 150 km/h, (90 mph).[3] However the JTWC did not report until later that day that Keli has reached its 1-minute peak windspeeds of 215 km/h (130 mph), which made it a Category 4 tropical cyclone on the SSHS after rapidly intensifying in an area of low vertical windshear.[4] The JTWC then passed the warning responsibility for Keli back to the NPMOC as it came under the influence of strong mid latitude westerlies which were expected to weaken the system.[4]

During June 13 both RSMC Nadi and the NPMOC reported that Keli had weakened as it began to experience vertical windshear from the northwest as it started the transition into an extratropical cyclone.[3][4] At this time RSMC Nadi reported that the system had become a Category 2 cyclone while the JTWC downgraded Keli to a tropical storm as it was located about 400 km (250 mi) to the southeast of the Somoan Islands.[3][4] During June 14, RSMC Nadi downgraded the cyclone to a Category 1 cyclone before it was declared extratropical by the JTWC early the next day as it had started to accelerate to the southeast while RSMC Nadi downgraded it to a Tropical Depression.[3][4] RSMC Nadi then continued to issue warnings on the depression until early on June 16 when they passed primary warning responsibility of Keli to TCWC Wellington, as the depression had passed to the south of 25S and had entered TCWC Wellington's area of responsibility.[3] TCWC Wellington continued to monitor the depression until early the next day when they issued their last advisory.[3]

Differences among warning centers

The Regional Specialized Meteorological Center in Nadi, Fiji uses the Australian Tropical Cyclone Intensity Scale which is based on 10-minute sustained winds and three second gusts for its tropical cyclone tracking information, while both the Joint Typhoon Warning Center and the Naval Pacific Meteorology and Oceanography Center use 1-minute sustained winds.[5] The conversion factor between the two is 1.14.[6] RSMC Nadi's peak intensity for Keli was 150 km/h, (90 mph) 10-minute sustained, or 170 km/h (105 mph) 1-minute sustained.[3][6] The JTWC's peak intensity for Keli was 215 km/h (130 mph) 1-minute sustained, or 190 km/h (120 mph) 10-minute sustained.[6][7]

Impact and aftermath

Image of Keli at peak intensity on June 12, 1997

Tuvalu

As Cyclone Keli struck the islands of Tuvalu on June 12 and 13, peak wind gusts of 165 km/h, (105 mph) were reported, with extensive damage also reported throughout the Islands with trees uprooted by wind and waves.[8] On Nivalakita all buildings except for the church were flattened with an estimated cost to rebuild the houses exactly as they were was estimated at AU$12,000 (US$10,000 1997), while it was estimated that the cost of rebuilding the houses with an improved, cyclone-resistant design would be about AU$84,000 (63,000 USD 1997).[9] Also on Nivalakita communications were cut with the telephone operator having to resort to sending a Morse code message, however as the storm re-curved and re-hit Tuvalu on June 14, it silenced the weak radio telegraph system.[8] In Tepuka Savilivili the whole island was left uninhabitable as coconut trees and other vegetation were swept away with no more than an area of jagged coral left behind.[10][11] An New Zealand air force transport plane was dispatched to the islands carrying with them water and tarpaulins which had been provided by Australia, France and New Zealand.[12]

Elsewhere

The storm produced strong winds, rough seas and heavy swells in Fiji as it moved north of the archipelago.[2] About 3.76 inches (95.5 mm) of rain was reported in Afono, American Samoa.[13]

After the season ended, it was announced that the name Keli would be retired from RSMC Nadi's List of tropical cyclone names and would be replaced with the name of Kofi.[14][15]

See also

References

  1. ^ "Tropical Cyclone Information for the Southern Hemisphere". Bureau of Meterology. 2009. Retrieved 2009-08-31.
  2. ^ a b "Asia-Pacific Workshop on Indicators and Indices for Monitoring Trends in Climate Extremes". Bureau of Meteorology. 1998-12-10. p. 43. Retrieved 2009-08-26.
  3. ^ a b c d e f g h i j k l m "South Pacific Tropical Cyclone Best Track". Fiji Meteorological Service, Meteorological Service of New Zealand Limited. NOAA. 2009-05-22. Retrieved 2009-08-07.
  4. ^ a b c d e f g h i j k "Tropical Cyclone Keli Advisories". Naval Pacific Meteorology and Oceanography Center/Joint Typhoon Warning Center. Australian Severe Weather. 2009. Retrieved 2009-08-07.
  5. ^ Joint Typhoon Warning Center (2008-03-31). "Frequently Asked Questions". United States Navy. Retrieved 2009-06-29.
  6. ^ a b c "Section 2 Intensity Observation and Forecast Errors". United States Navy. 2009. Retrieved 2009-06-29.
  7. ^ "JTWC/NPMOC Tropical Cyclone Best Track: 38P". Joint Typhoon Warning Center. 2002-12-17. Retrieved 2009-08-31.
  8. ^ a b "EARTHWEEK: A diary of the planet". The Gainesville Sun. 1997-06-24. Retrieved 2009-08-30.
  9. ^ "Tool One: Guidelines for estimating the economic impact of natural disasters" (PDF). Aus Aid. 2006-03-17. Retrieved 2009-08-30. {{cite web}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  10. ^ "Tuvalu and Global Warming". Tuvalu Islands. 1997-12-07. Retrieved 2009-08-30. {{cite web}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  11. ^ "Sinking feeling in Tuvalu". BBC News. 2002-08-28. Retrieved 2009-08-30. {{cite web}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  12. ^ "Aid on way to cyclone struck isle". The Register Guard. Guard Publishing Company. 1997-06-15. Retrieved 2009-08-30.
  13. ^ David Roth (2009-08-30). "Tropical Cyclone Rainfall Maxima". National Oceanic and Atmospheric Administration. Retrieved 2009-08-30.
  14. ^ "Tropical Cyclone Operational Plan for the Southwest Indian Ocean and the Southern Pacific Ocean" (PDF). RA V Tropical Cyclone Committee. World Meteorological Organization. 2009-03-10. Retrieved 2009-05-21.
  15. ^ "Tropical cyclone old names: Fiji". Met Office. 2009-08-30. Retrieved 2009-08-30.
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