[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 200524
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1224 AM EST Wed Dec 20 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 0000 UTC surface analysis and satellite imagery through
0515 UTC.

...SPECIAL FEATURES...

...Gale Warning in the Caribbean Sea...

Pulsing nocturnal easterly winds to gale-force are expected again
tonight near the coast of Colombia, particularly from 11N to 13N
between 74W and 76W. Expect sea heights to range from 10 to 14 ft
within the area of gale-force winds, with a larger area of 8-11
ft seas extending into the west-central Caribbean. Winds will
diminish below gale-force by Wednesday morning. Thereafter, strong
to near-gale force winds will persist in the area each night this
week. Please read the latest NHC High Seas Forecast under AWIPS/WMO
headers MIAHSFAT2/FZNT02 KNHC for more details.

...ITCZ/MONSOON TROUGH...

The monsoon trough enters the Atlantic Ocean from 07N13W to
03N26W. The ITCZ extends from 03N26W to northeast Brazil near
02N51W. Scattered moderate convection is noted from 00N-05N
between 06W-11W.

...DISCUSSION...

...GULF OF MEXICO...

A surface ridge dominates the Gulf, anchored by a 1023 mb high
centered over the Florida Big Bend. Scatterometer and surface data
depict gentle to moderate anticyclonic flow across the basin,
with seas generally below 5 ft. Patchy fog will develop again
tonight into the early morning hours along the Gulf coast from the
western Florida Panhandle all the way westward to across most of
the coast of Texas. The visibility is expected to drop below one
mile. Dense fog advisories are in effect for the coastal waters.
The surface high will move eastward over the next 24 hours. A
weak cold front will reach the coast of Texas on Wednesday, and
stall across the northern Gulf by Thursday, then move north as a
warm front by late Thursday. A stronger cold front will reach the
northwest Gulf on Friday, and move southeast across the basin
through the weekend. Fresh southerly return flow is expected
across the western Gulf ahead of the front. Fresh to strong
northerly winds and building seas will follow the front.

...CARIBBEAN SEA...

Please refer to the Special Features section for details about
the gale warning near the coast of Colombia. The most recent
scatterometer data indicated fresh to strong winds across the
basin roughly between 70W and 83W. An altimeter pass indicated
seas of up to 14 ft over the southwest Caribbean in association
with the strong to minimal gale force winds. Fresh to strong
easterly winds are expected in the lee of Cuba and across the
Windward Passage through Wed night. Broad mid to upper-level
anticyclonic wind flow and strong subsidence dominates the entire
basin producing generally dry conditions. Despite this, patches of
low-level moisture embedded in the trade wind flow are moving
across the area producing isolated to scattered passing showers.

...HISPANIOLA...

As previously mentioned, broad mid to upper-level anticyclonic
wind flow and strong subsidence dominates the entire Caribbean
Sea supporting mostly stable conditions. However, low-topped
trade wind showers will continue to affect the island from time
to time tonight and Wednesday.

...ATLANTIC OCEAN...

A deep layer trough in the eastern Atlantic is supporting a
stationary frontal boundary that extends from 31N39W to 21N59W.
This front will dissipate over the next 24 hours. Mainly low-
level clouds with isolated showers are along the front. A surface ridge
is noted in the wake on the front, with a 1022 mb high centered
just east of the Bahamas near 26N75W. East of the front, the
Azores high dominates the remainder of the eastern Atlantic. A
second cold front is approaching from the north in the west
Atlantic, and now extends from 32N55W to 32N68W. The high
pressure over the western Atlantic is forecast to dissipate as the
the second cold front reaches from 31N58W to the NW Bahamas by
Wednesday morning, then the front will stall and begin to
dissipate. Another cold front will reach the waters east of
northern Florida by Thursday morning and extend from 31N58W to
27N65W to along 27N to near the NW Bahamas. Moisture associated
with this front may reach south Florida on Friday.

For additional information please visit
http://www.hurricanes.gov/marine

$$

ERA

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