Tropical Weather Discussion
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AXNT20 KNHC 212359

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
659 PM EST Tue Feb 21 2017

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 1800 UTC surface analysis and satellite imagery through
2345 UTC.


A 1010 mb surface low associated with an anomalously south deep-layer
low is near 23N63W. A cold front extends from the low to 17N62W to
14N69W. These features are within a broad area of low pressure
that prevails over the central Atlantic. A second cold front
enters the area through 32N56W to 26N75W. This cold front will
merge with the cold front previously described by tonight. The
merged frontal boundary will then continue moving east enhancing
winds/seas. A tight pressure gradient will become established
between the front and a strong high pressure to its east, inducing
gale-force winds north of 27N within 240 nm east of the front
starting at 22/00Z. These winds are expected to lift north of the
discussion by Wednesday night. See the latest NWS High Seas
Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more


The Monsoon Trough extends from the African coast near 08N14W to
03N19W. The Intertropical Convergence Zone extends from 03N19W to
00N46W. Isolated showers are observed along the ITCZ.



A cold front extends across the central Gulf from 30N87W to
18N94W. A squall line was analyzed ahead of the front from 30N86W
to 28N87W. Scattered moderate convection prevails along these
features mainly north of 26N. Scatterometer data depicts moderate
to fresh northerly winds west of the front while gentle to
moderate southerly winds prevail east to the front. A surface
trough extends across the northwest Gulf from 30N94W to 28N94W
with isolated showers and thunderstorms. Expect for the front to
continue moving east through the next 24 hours. Latest guidance
forecasts a surface low developing across the eastern Gulf
tonight. The low will move east across the Florida Peninsula
through Wednesday enhancing winds and convection.


Overall, the Caribbean basin continues under fairly tranquil
conditions at this time, with the exception of the northeastern
waters. Isolated showers are observed over Cuba and its adjacent
waters north of 18N. An area of low pressure centered N-NE of
Puerto Rico extends a cold front that crosses the Lesser Antilles
and eastern Caribbean waters from 17N62W to 14N68W. A a pre-
frontal trough is also evident in observations across the Windward
Islands from 16N61W to 13N63W. Isolated showers are observed along
these features. Scatterometer data depicts gentle to moderate
northeasterly trades across most of the basin mainly west of 70W.
Moderate northerly winds are prevailing north of the front
affecting the waters north of 15N between 60W-70W. Light to
moderate southerly winds prevail south of the front and east of
70W. Expect during the next 24 hours for the cold front currently
over the Gulf of Mexico to enter the west Caribbean enhancing
winds/convection. The frontal boundary over the east Caribbean
will continue moving east while weakening.


Fair weather prevails across the island at this time. Patches of
low-level moisture moving southward due to northerly flow to the
west of the Atlantic low pressure system and cold front, will
approach the north coast of the island tonight increasing the
chance for precipitation. Any shower activity that approaches the
north coast will be moving rather quickly to the south.


Scattered showers prevail across the west Atlantic mainly west of
74W. To the east, a cold front extends from 31N57W to 26N75W. No
significant convection is related to this front at this time. A
1010 mb low is centered near 23N63W, with a cold front extending
south-southwest across the Lesser Antilles and eastern Caribbean.
An area of scattered showers prevails to the east of these
features affecting the waters between 48W-56W. Expect for the
cold fronts to merge near 60W tonight. Gale-force winds are
expected to develop near the new front. Please refer to the
section above for details.

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