Typhoon Forrest (1983)
|Category 5 super typhoon (SSHS)|
Super Typhoon Forrest near peak intensity
|Formed||September 20, 1983|
|Dissipated||September 29, 1983|
|Highest winds||10-minute sustained:
205 km/h (125 mph)
280 km/h (175 mph)
|Lowest pressure||885 mbar (hPa); 26.13 inHg|
|Fatalities||21 direct, 17 missing|
|Part of the 1983 Pacific typhoon season|
Super Typhoon Forrest was a powerful super typhoon that affected Japan in September 1983. Typhoon Forrest formed from a tropical disturbance far from land. On September 20, the system was classified as a tropical storm, and thereafter, began to intensify. The next day, Forrest reached typhoon status, and the intensification process accelerated. The storm prudently strengthened on September 22, and the following morning, attained peak intensity. Thereafter, Forrest began to weaken slowly as it moved northwest. Approaching Japan, Super Typhoon Forrest first hit Okinawa on September 27. Nearby, a tornado hit Inza Island, destroying 26 homes and injuring 26 people. Forrest then moved north impaling the elongated Japanese archipelago before transitioning into an extratropical cyclone on September 28. The torrential rainfall caused by the typhoon triggered deadly landslides and flooding across Japan. In all, the cyclone killed at least 21 people, left 17 listed as missing, injured 86 and flooded 46,000 homes in muddy water. Over 100 dwellings were destroyed. In addition, 67 bridges and 818 roads were damaged. A total of 2,560 people were rendered as homeless. Seven flights were called off, leaving 27,000 persons stranded.
Typhoon Forest originated from an area of disturbed weather that was first noted by the Joint Typhoon Warning Center (JTWC) around 555 km (345 mi) west of Ponope. Initially, the system was not well-organized; however, it had a sufficient amount of convection. Hurricane Hunters investigated the system four times from September 17-20, though none of them was able to identify a closed atmospheric circulation. Despite this, a Tropical Cyclone Formation Alert (TCFA) was issued on September 18. This alert was issued again on September 19; meanwhile, the Japan Meteorological Agency (JMA) started to monitor the system. By early on September 20, the JMA upgraded the system into a tropical storm as it moved west-northwest.[nb 1] During the evening hours of September 20, the JTWC started issuing warnings on the system after the low developed a central dense overcast. At this time, the storm was located about 330 km (210 mi) south of Guam. Initially, only gradually strengthening was expected by the JTWC, but this did not occur and by the morning hours of September 21, Hurricane Hunters measured winds of 95 to 115 km/h (60 to 70 mph). Based on this, the JTWC classified the system as a tropical storm and named it Forrest. Around this time, JMA upgraded Forrest into a severe tropical storm.
By 1800 UTC that day, both the JTWC and the JMA upgraded Forrest to typhoon status. After moving away from Guam, Forrest continued deepening, by the evening hours of September 21, Hurricane Hunters estimated a minimum barometric pressure of 975 mbar (28.8 inHg). Eleven hours later, however, the aircraft reported a pressure of 883 mbar (26.1 inHg), according to the JTWC, this marked a pressure drop of 92 mbar (2.7 inHg) in a little under a day. Midday on September 22, the JTWC assessed the intensity of the storm at 280 km/h (170 mph), equivalent to a Category 5 hurricane on the Saffir-Simpson Hurricane Wind Scale. Despite this, the JMA estimated that Forrest had winds of only 85 mph (135 km/h). However, several hours later, the agency estimated winds of 135 km/h (85 mph). At 0000 UTC on September 23, the JMA reported that Forest attained peak intensity, with winds of 160 km/h (100 mph) and a minimum pressure of 885 mbar (26.1 inHg).
After attaining peak intensity, the storm weakened slightly on September 24 according to the JMA, though the storm briefly restrengthened to its peak wind speed at noon on September 25. By this time, Forrest was moving northwest, and the JTWC expected the storm to recurve due to a weak spot in the subtropical ridge. However, the re-curvature took longer than expected. The JMA suggested that the storm maintained its intensity of 200 km/h (120 mph) for a couple days. On September 27, however, the JMA estimated that Forrest finally began to weaken. The storm quickly weakened thereafter, and by midday, the JMA downgraded the system into a severe tropical storm. On September 28, both the JMA and the JTWC reported that Forrest had completed its extratropical transition just south of Shikoka. The JTWC issued its last warning on the system at 0000 UTC on September 29 while estimating winds of 65 km/h (40 mph). The JMA, however, did not cease monitoring the extratropical remnants of Forrest until September 30.
Preparations and Impact
During its formative stages, the storm passed near Guam, resulting in winds of 32 km/h (20 mph). Rainfall was light, totaling 51 mm (2.0 in), but was enough to result in slight flooding.
While weakening and passing 200 km (120 mi) southwest of Okinwana, gusty winds and heavy rains were recorded. At the Kedana Air Base, winds of 95 km/h (59 mph) and gusts of 80 mph (130 km/h) were measured. Rainfall of 296 mm (11.7 in) was recorded, leading to minor flooding. A few people were hurt due to high winds, but according to the JTWC, the residents of Okinwana weathered the storm "well". Numerous funnel clouds were spotted, but no tornadoes were recorded. Northwest of Okinwana, on Inaka Island, a tornado was reported, resulting in a swath of 91 m (299 ft). Seven homes were destroyed and 26 people were hurt, including some serious. When the storm posed a threat to Kyushu, five ships were evacuated to an air force base that was considered "safe typhoon heaven". In Motoyama, 540 mm (21 in) of rain fell, including 415 mm (16.3 in) in 24 hours and 102 mm (4.0 in) in one hour. In Nagoya, five children were washed away by rising floodwaters while they were walking home from school. Four of the children were confirmed dead, and one 5-year-old child was reported missing. In Nishinomiya, near the western city of Kyoto, twelve construction workers were swept away by a downpour-triggered mudslide. Four of the construction workers were rescued, but the remaining eight of the construction workers were missing. Elsewhere in the city, a landslide destroyed two homes, resulting in the deaths of a 71-year old and a 77-year old farmer. Around 60 mi (95 km) south of Tokyo, in Shizuoka, three construction workers were swept along the Nishi River. In Hoygo, on Honshu, 12 people were buried alive when a hut collapsed due to a mudslide. Throughout the island of Okinawa, 30 sustained minor injuries and 20 homes would either damaged or destroyed. About 160,000 customers lost power.
In all, Forest killed at least 21 people, left 17 missing, and injured 86. Due to overflowing rivers and dikes, 46,000 homes were flooded, including 141 "seriously". Around 7,700 homes were "under water", and over 100 were destroyed. In addition, 67 bridges and 818 roads were damaged. A total of 2,560 people were homeless. Seven flights were called off, stranding 27,000 persons. Train service was halted for hours and truck lines were damaged in eight places.
- Hurricane Wilma — Explosively deepened from a Tropical Storm to category 5 hurricane in a day with a 97 millibar pressure drop in the same time period.
- Hurricane Katrina — Also intensified explosively
- Hurricane Rita — Intensified explosively
- Cyclone Ului — A very fast intensifying cyclone
- Typhoon Chebi (2006) — Went from tropical storm status to category 4 status in just under a day
- Typhoon Sanba (2012) — Under went an 80 Millibar pressure drop in one day.
- List of tropical cyclones
- 1983 Pacific typhoon season
- Joint Typhoon Warning Center; Naval Western Oceanography Center (1984). Annual Tropical Cyclone Report: 1983 (Report). United States Navy, United States Airforce. pp. 53-56. http://www.usno.navy.mil/NOOC/nmfc-ph/RSS/jtwc/atcr/1983atcr.pdf. Retrieved September 30, 2013.
- Japan Meteorological Agency (October 10, 1992) (.TXT). RSMC Best Track Data – 1980–1989 (Report). http://www.jma.go.jp/jma/jma-eng/jma-center/rsmc-hp-pub-eg/Besttracks/bst8089.txt. Retrieved September 20, 2013.
- "Annual Report on Activities of the RSMC Tokyo – Typhoon Center 2000" (PDF). Japan Meteorological Agency. February 2001. p. 3. Retrieved September 20, 2013.
- Digital Typhoon (March 19, 2013). "Typhoon 198310 (FORREST)". Digital Typhoon Detailed Track Information (National Institute of Informatics). http://agora.ex.nii.ac.jp/cgi-bin/dt/dsummary.pl?id=198310&basin=wnp&lang=en. Retrieved November 11, 2013.
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- "Typhoon Forest Deaths Up to 21". Sarasota Herald-Tribune. September 30, 1983. Retrieved 12 November 2013.
- "Typhoon Forrest Kills 8, Leaves 2,500 Japanese Homeless". The Telegraph-Herald. September 28, 1983. Retrieved November 11, 2013.
- "Toll from typhoon mounts in Japan". The Bulletin. September 28, 1983. Retrieved November 11, 2013.