Tropical Weather Discussion
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AXNT20 KNHC 191738

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
138 PM EDT Thu Apr 19 2018

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South America,
and Atlantic Ocean to the African coast from the Equator to 32N.
The following information is based on satellite imagery, weather
observations, radar and meteorological analysis.

Based on 1200 UTC surface analysis and satellite imagery through
1700 UTC.


The monsoon trough along the coast of Africa near 10N14W extends
southwestward to 06N16W and then westward to 03N22W. The ITCZ
continues weatward from 03N22W to 01N51W. Scattered moderate
showers and isolated thunderstorms were occurring within 90 nm
either side of the ITCZ and monsoon trough.



A ridge extending westward from central Florida to the northeastern
coast of Mexico will shift eastward ahead of a cold front moving
southward over the northern and northwestern Gulf, with the front
becoming stationary from south Forida to south Texas by Friday
morning. Light to moderate E to SE winds continue over most of the
Gulf, with 1 to 3 ft seas in the northeast Gulf and 2 to 4 ft seas
elsewhere. Visibility will remain unrestricted across the Gulf,
and no showers or thunderstorms expected into Friday morning.

Fresh to occasionally strong northerly flow behind the front will
spread southward over the northern Gulf N or 27N into this evening.
After stalling across the central Gulf on Friday, the front will
drift north over the western Gulf as a warm front by Fridat
afternoon. Fresh to strong easterly winds are expected over the
northeastern Gulf into Sat as high pressure builds north of the
area behind the front. The front will weaken across Florida and
the eastern Gulf on Sat, possible returning northward as a warm
front on Sunday, ahead of another cold front that will emerge off
the Texas coast late Sat night/early Sun morning. This second
weak front will extend from the mouth of the Mississippi River
southwestward to near Veracruz Mexico by late Sun, and from the
Florida Panhandle to the northeastern Yucatan peninsula by late
Monday, followed by moderate northerly winds.


An upper trough over the Windward Passage is aiding the development
of scattered showers and isolated thunderstorms across Puerto
Rico and Hispaniola, and the adjacent Caribbean and Atlantic
coastal waters. Elsewhere, fresh to strong NE to E winds persist
off the coastlines of northwest Venezuela to Colombia with 8 to 10
ft seas. Otherwise, moderate winds and seas, accompanied by dry
conditions persist across the basin.

For the forecast, building high pressure north of the area will
maintain fresh to locally strong tradewind flow along the north
coast of South America today. These winds will expand northward
over the south central Caribbean into the southwest Caribbean
through Fri, then diminish somewhat late this weekend into early
next week. Northeasterly swell will increase east of the Leewards
tonight and Friday, then decay from west to east through Sun.


A weak, stationary surface trough extended from 31N61W to 25N71W.
A few isolated showers were occuring along and within 60 nm of the
trough. The weak trough will drift westward today, becoming diffuse
this afternoon and dissiapting tonight. Moderate to fresh southerly
flow is noted off the northeast coast of Florida between the ridge
and lower pressure over the southeast United States. Seas are
generally 3 to 5 ft in open waters. A cold front will move off
the northeastern Florida coast by tonight and reach from near
Bermuda to south Florida by late Fri, then stall from 26N65W to
the Straits of Florida by late Sat. Remnants of the front will
lift northward on Sun ahead of another cold front that will move
eastward across the southeastern United States and enter the
northwest waters by late Tue.

Farther east, a 1032-mb high was centered near 34N38W was producing
moderate to fresh trade winds over the deep tropics. Large long
period northerly swell persists, with 12 to 14 ft seas covering
the region north of 20N east of 50W, and 8 to 12 ft seas present
north of 12N and east of 55W.

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