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Atlantic Tropical Weather Discussion

AXNT20 KNHC 110503

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1203 AM EST Mon Dec 11 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 
0415 UTC.

A cold front extends across the SW North Atlc waters from 32N64W 
SW to the Windward Passage and then to the SW Caribbean Sea near
11N79W. Strong high pressure continues to build in W of the front
across Cuba...the NW Caribbean Sea...and much of Central America 
this evening resulting in near gale to gale force N winds 
generally S of 18N W of the front to 83W off the coast of
Nicaragua. As the front creeps eastward and eventually begins to 
stall by Monday morning...the remaining boundary will extend from
the Windward Passage region to the coast of Costa Rica with fresh
to strong N winds continuing to diminish gradually through mid- 
week. See the latest NWS High Seas Forecast under AWIPS/WMO 
headers MIAHSFAT2/FZNT02 KNHC for more details.

The monsoon trough extends from the African coast near 06N11W to 
05N22W. The Intertropical Convergence Zone axis extends from 
05N22W to 03N32W to 06N41W. No significant deep convection noted
on satellite imagery at this time.


A surface ridge extends across the entire basin anchored by a 
1031 mb high centered across northern Mexico near 27N100W. Light
to gentle N winds are noted W of 90W...and gentle to moderate N 
winds are noted E of 90W. The ridging will build in across the 
northern Gulf through Monday night with generally gentle to 
moderate anticyclonic winds expected across much of the basin. By 
Tuesday...the next weak cold front will emerge off the SE CONUS 
coast introducing a brief period of fresh W-NW winds to the
northern water Tuesday morning and eastern waters Tuesday
afternoon into the evening. The front will be quick to clear east
of the basin with moderate northerly winds prevailing Wednesday 
into Thursday.

The primary feature across the basin is the cold front extending
across the western waters generating the near gale to gale force
northerly winds. Scattered showers and tstms are occurring 
generally S of 18N between 76W-84W...and within 60 nm either side
of the cold front N of 18N. Much of this convection is supported 
aloft by a divergent upper level pattern on the western periphery
of an upper level anticyclone anchored over northern Colombia near
11N75W. East of the anticyclonic circulation...dry northerly flow
prevails providing overall stability to the central and eastern 
Caribbean this evening. A few isolated showers are noted on 
satellite imagery across the NE Caribbean...but remain quick- 
moving and embedded within gentle to moderate trades. The front 
is forecast to become stationary across the western Caribbean and
begin to gradually weaken through mid-week.

Fair weather conditions prevail across the island this evening
while a cold front remains analyzed across the Windward Passage
region. Isolated showers and tstms are possible within 60 nm
either side of the front which is expected to stall overnight into
Monday and begin a weakening trend through Tuesday night.

Water vapor imagery indicates a middle to upper level trough over
the eastern CONUS and western North Atlc waters supporting the
Special Features cold front extending from 32N64W to the Windward
Passage and into the SW Caribbean Sea. Isolated showers are 
occurring within 120 nm either side of the front. Otherwise...the
remainder of the SW North Atlc waters are under the influence of 
a surface ridge anchored over the Gulf of Mexico and portions of
NE Mexico. Elsewhere...water vapor imagery indicates a cut-off 
middle to upper level low centered near 24N48W that continues to 
slowly retrograde. A surface trough extends from 20N47W to 29N44W
providing focus for scattered showers and tstms from 19N-28N 
between 39W-49W. The trough is forecast to drift westward across 
the central Atlc through Monday night.

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