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Grace Dissipates; TD 8 Forms South of Newfoundland

By: Jeff Masters 3:27 PM GMT on September 09, 2015

Tropical Depression Eight spun into life on Wednesday morning in the waters a few hundred miles east-southeast of Bermuda, and appears poised to become Tropical Storm Henri by Thursday. TD 8 is under high wind shear of 20 knots, which is inhibiting development, but ocean waters are warm, near 28.5°C (83°F). The 8 am EDT Wednesday run of the SHIPS model predicted that by Thursday, TD 8 should find moderate wind shear of 5 - 15 knots and a much moister atmosphere, which should allow it to become a tropical storm. By Friday afternoon, TD 8 will move northwards across the warm waters of the Gulf Stream, and encounter very cold waters near 23°C (73°F), which should cause a rapid transition to an extratropical storm. TD 8 will likely pass over or near southeast Newfoundland, Canada on Saturday morning.

Figure 1. Latest satellite image of TD 8.

Grace dissipates
Tropical Storm Grace finally succumbed to dry air and high wind shear and dissipated on Wednesday morning. The remains of Grace could produce some gusty winds and showers over portions of the Lesser Antilles on Friday.

Gulf of Mexico disturbance next week
An area of disturbed weather is expected to form in the Western Gulf of Mexico's Bay of Campeche on Sunday or Monday next week. This disturbance will be capable of developing into a tropical depression, and could bring heavy rains to the coast of Mexico south of Texas early next week.

Figure 2. Hurricane Linda near peak intensity as seen by the GOES West satellite at 2 pm EDT September 8, 2015. At the time, Linda was a Category 3 storm with 125 mph winds. Image credit: NOAA Viz Lab.

Three tropical cyclones in the Pacific
In the Eastern Pacific off the coast of Mexico's Baja Peninsula, Hurricane Linda put on a spectacular show on Tuesday, peaking as a Category 3 storm with 125 mph winds--the Northeast Pacific's fifth major hurricane of the season. A northeasterly flow of moisture along the east side of Linda is streaming into Northwest Mexico and the Southwest U.S., and will contribute to numerous thunderstorms with heavy rain over the next two days. Flash flood watches are posted for Southwest California for the regions just inland from San Diego to Los Angeles. As of 11 am EDT Wednesday, Linda had weakened to a Category 1 storm with 80 mph winds, and is expected to continue to weaken to tropical depression status by Thursday, well offshore from Mexico. In the Central Pacific waters 320 miles north of Honolulu, Hawaii, Jimena has weakened to a tropical depression with top sustained winds of 35 mph at 11 am EDT Wednesday. Jimena will continue to weaken over the next few days, and will not bring heavy rain to Hawaii. Long-lived Category 1 Typhoon Kilo is now in its 21st day as a tropical cyclone and 12th day at hurricane strength. Kilo is predicted to move on a northerly path that will take it into the cold waters between Russia and Japan on Friday, when it will finally die after 23 - 24 days as a tropical cyclone.

Tropical Storm Etau hit Japan just after 10 a.m. on Sept. 9 on the Chita Peninsula, Aichi Prefecture. A band of heavy rain associated with Etau is hammering the Tokyo metropolitan area. As of 11 am EDT Wednesday, evacuation advisories are currently in effect for about 697,000 people. The vast majority (626,000) are in the city of Kawasaki, just south of Tokyo. According to JMA, the highest 24-hour rainfall total is currently 398 mm (15.67 inches) in Dorobu, part of the city of Nikkō in Tochigi Prefecture. That's the highest 24-hour total ever recorded at that location since observations began there in 1977. The top 72-hour total is 438 mm (17.24 inches) in Okunikkō, which is also part of the city of Nikkō (thanks go to TWC's Nick Wiltgen for this info.)

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Today (September 9) is the 50th anniversary of Category 3 Hurricane Betsy hitting Louisiana. Storm Surge expert Hal Needham has a blog post analyzing Betsy's storm surge.

Jeff Masters


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