Thursday, July 17, 2014

Tropical Update: Typhoon Rammasun, Tropical Storm Matmo in Western Pacific; Tropical Depression One-C East of Hawaii

Stu Ostro
Published: July 17,2014





 
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Atlantic Basin Satellite Image

Atlantic Basin Satellite Image
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Eastern Pacific Basin Satellite Image

Eastern Pacific Basin Satellite Image
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Western Pacific Basin Satellite Image

Western Pacific Basin Satellite Image
- Typhoon Rammasun (known as Glenda in the Philippines) restrengthens into a Category 4 equivalent typhoon
- Headed for Hainan Island tomorrow with strong winds, heavy rainfall
- New Tropical Depression forms in the western Pacific but no immediate threat to land
- First Tropical Storm of 2014 in the central Pacific

Western Pacific

Typhoon Rammasun has re-intensified significantly into a Category 4 equivalent cyclone as it approaches southern China and northern Vietnam.
(MORE: Rammasun Forecast | News/Photos)
Rammasun took advantage of a favorable atmosphere and very warm ocean waters today to once again restrengthen over the South China Sea. The now Category 4 equivalent typhoon may strengthen further before it impacts the city of Haiko and Hainan Island over the next 6-12 hours. The primary impacts will be flash flooding from heavy rainfall in addition to very powerful winds near the center.
Rammasun is expected to weaken some before moving over south China and Vietnam this weekend.
Tropical Storm Matmo (10W) has formed well east of the Philippines, near the island of Yap.
Models differ on the amount to which Matmo will strengthen, while generally being in agreement on a track skirting to the northeast of the northern Philippines late in the weekend into early next week. The storm may threaten southern Japan as a typhoon by the early to middle part of next week. We'll watch model forecast trends in case that is toward a more direct and significant impact to Japan so soon after just getting hit.

Central Pacific

Satellite information received within the evening hours Thursday has prompted the Central Pacific Hurricane Center to upgrade Tropical Depression One to Tropical Storm Wali about 1,000 miles east-southest of the Big Island of Hawai'i. There are no changes to the previous forecast and Wali is expected to weaken before reaching Hawai'i. Some of its residual rainfall could spread over the island state by Sunday into Monday.

Atlantic

A lot of thunderstorms are also in the northern Gulf of Mexico and extending across Florida and to offshore of the Carolinas. That is all associated with the periphery of the dip in the jet stream over the central-eastern U.S. which is unusually deep for July, and ahead of a cold front which has pushed far to the south for this time of year.
Sometimes, especially later in the season, when it's more typical for such fronts, one will dangle and its thunderstorms will fester and a low pressure system will develop which takes on tropical characteristics. Models are showing that a weak low might be off the southeast U.S. coast by this weekend. Becoming anything more would have to be considered a long shot at this point (it's just a little annoying to see the prospect of a low pressure system being where the first hurricane of the Atlantic season formed recently). 
Speaking of later in the season, as the calendar progresses from June and early July to late July and August, we start looking out across the central and eastern tropical Atlantic, in addition to still monitoring the Gulf, Caribbean, and subtropical Atlantic, for increased potential for tropical storm development. 
Nothing developing for the foreseeable future there, yet a solid low-level spin depicted by a model forecast this weekend into early next week associated with a tropical wave coming off Africa (also called an African easterly wave) is a sign of the times, as on average this is when the climatologically favored areas in the tropics start evolving as the August-September peak of the season approaches, which is also the Cape Verde season, so-called because of the country in the eastern Atlantic near where these systems pass.
(MORE: Glossary of Tropical Terminology | New NHC Storm Surge Maps in 2014)

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MORE: Hurricanes From Space (NASA Satellite Images)

NOAA's GOES-13 satellite captured this visible image of Post-Tropical Sandy rolling inland on Oct. 30, 2012, at 6:02 a.m. EDT. (1302 UTC). (NASA)
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