Typhoon Jelawat

Pre-Landfall 1 | Summary
Posting Date: September 28, 2012, 10:45:00 AM

Typhoon Jelawat is projected to pass over Okinawa tomorrow. Briefly a super typhoon on Tuesday—the equivalent of a Category 5 hurricane with 160mph winds and one of the strongest tropical cyclones this year (second only to Typhoon Sanba)—Typhoon Jelawat’s winds have weakened to 120 mph, or a Category 3 storm, with a central pressure of 925 mb. Typhoon Sanba, which passed over the Pacific less than two weeks ago was also a super typhoon; it is rare for two consecutive super typhoons to develop in the Pacific. Typhoon Jelawat is moving in a north-northeasterly direction at 12 mph. It is approximately 285 miles southwest of Kadena Air Base, Okinawa, Japan. The Japanese Meteorological Agency has issued a weather warning for Okinawa and advisories for parts of Kyushu (South), Shikoku, Kinki, Tokai, Kanto/Koshin, and Tohoku prefectures.

Meteorological History

On Wednesday, Jelawat was positioned northeast of the Philippines and moving in a northerly direction roughly parallel with the country, causing heavy rains in the northern part of Luzon Island. As it headed toward Taiwan, the Central Weather Bureau (CWB) issued a Sea Warning on Thursday, which it lifted today. The CWB posted rain advisories ranging from heavy rain to extremely torrential rain. As of 8:30 p.m., local time, today (00:30, UTC) 208.5 mm of rainfall had accumulated on Taiping Mountain, which is the highest recorded amount; the next highest amount, 178 mm, fell on Niaozuishan in Hsinchu County; and 153 mm fell on Piglin District in New Taipei. In addition the CWB has posted a strong wind advisory, which remains in effect.

Forecast and Intensity

As Jelawat turns northeastward, it will slowly lose some of its impressive strength, but not before it crosses Okinawa, making it the third typhoon this year to affect this small island prefecture. Okinawa is no stranger to typhoon activity but experiencing three direct hits from typhoons—let alone strong ones in a single season—is a first. After Okinawa, Jelawat will take aim on the main islands of Japan. Because the storm will be approaching from the southwest and because of Japan’s coastline and orientation, it is still difficult to tell exactly where, or even if, Jelawat will make landfall. The forecast location will be complicated by interaction with an approaching cold front, which may pull Jelawat more northward and keep it from getting too close to Tokyo. As Jelawat moves northward, it will begin moving over colder water. That, plus its interaction with the approaching front that will bring it into an environment of stronger wind shear, will cause the storm to lose some strength before it reaches the mainland. How much strength it loses is still uncertain—and Jelawat has plenty of intensity to lose. It could still very well be the strongest typhoon to make landfall on the Japan mainland in five years. In July 2007, Typhoon Man-Yi made landfall in Kyushu with a central pressure of 945 mb and sustained winds of 100 mph. Jelawat could come close to that – impacting the coastline from Wakayama north to Shizuoka Prefectures as early as Sunday evening (local time) with strong winds and heavy rain. As Jelawat continues moving northward across Japan after landfall, it will begin extratropical transition and the threat will shift from damaging wind to flooding rain. The emerging El Nino conditions may have something to do with Jelawat’s intensity and track across Japan. Okinawa's predominantly concrete building stock is well prepared to handle storms of this intensity, so no significant structural damage is expected in the prefecture. Some damage can be expected from downed trees and flying debris, as well as to non-structural elements such as awnings and signage. The AIR tropical cyclone team continues to monitor Typhoon Jelawat closely and will issue additional updates as warranted.

Pre-Landfall 1 | Downloads
Posting Date: September 28, 2012, 10:45:00 AM