Tropical Weather Discussion
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AXNT20 KNHC 201738

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
138 PM EDT Fri Apr 20 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
1740 UTC.


The monsoon trough along the coast of Africa near 09N13W extends
southwestward to 00N22W. The ITCZ continues westward from 00N22W
to the coast of South America near 01S45W. Isolated moderate
convection is from 01S-02N between 30W-38W.



A cold front extends from N Florida near 28N83W to the central
Gulf of Mexico near 26N90W, continuing thereafter as a stationary
front to NE Mexico near 25N97W. The front is associated with very
little precipitation, but may spark some isolated showers along
the frontal boundary through the night tonight. A surface trough
is located in the Bay of Campeche and has some convective activity
associated with it, within the western half of the bay.

Expect the front to become stationary between the Florida Keys
and NE Mexico later this evening. Visibility will remain
unrestricted across the Gulf. The front will drift north over the
western Gulf as a warm front by later this evening. 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,
possibly 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 cold front will reach from
the Mississippi Delta to the Bay of Campeche on Sun night, from
the Florida Big bend coastline to the Yucatan Peninsula on Mon
night, then drift southeast on Tue and move southeast of the gulf
waters late Wed.


An upper trough over the Caribbean is aiding the development of
scattered showers and isolated thunderstorms across over N
Colombia and NW Venezuela, with fresh to strong NE to E surface
winds persisting off their respective coasts, along with 10 to 12
ft seas. Otherwise, moderate winds and seas accompanied by dry
conditions persist across the basin.

For the forecast, high pressure building in north of the area
will maintain fresh to locally strong tradewind flow along the
north coast of South America and central Caribbean Sea today,
then diminish somewhat late this weekend into early next week.
Northeasterly swell will continue to increase east of the
Leewards this evening, then decay from west to east through Sun.


A cold front will continue to move off the eastern Florida coast
today and reach from near Bermuda to south Florida by late today,
then stall from 28N65W 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 late Mon and enter the northwest waters by late Tue.

Farther east, a large 1034 mb high over the central Atlantic near
34N37W is producing moderate to fresh trade winds over the deep
tropics. Large long period northerly swell persists, with 10 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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