Tropical Weather Discussion
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AXNT20 KNHC 130551

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1251 AM EST Thu Dec 13 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 0000 UTC surface analysis and satellite imagery through
0515 UTC.


...Gulf of Mexico Gale Warning...

A cold front is forecast to enter the northwest Gulf of Mexico by
early this afternoon and extend from the Mississippi Delta to
Tamiahua Mexico tonight, from the Florida Big Bend to the Yucatan
Peninsula Fri morning and move E of area before sunrise on Sat.
Gale force winds are expected tonight through Friday afternoon
behind the front over the northwest and west-central Gulf waters.
Please read the latest High Seas Forecast under AWIPS/WMO headers
HSFAT2/FZNT02 KNHC for more details.


The monsoon trough extends from the coast of Sierra Leone near
07N12W to 02N24W. The ITCZ continues from that point to 01N30W to
01N40W to the coast of Brazil near 01S48W. Scattered moderate
convection is seen from 02N-04W between 39W-51W. Between the W
coast of Africa and 39W, isolated showers are noted near and
within 180 nm S of the monsoon trough and ITCZ.


A 1025 mb surface high is centered near the Florida/Georgia border
near 31N82W. The high extends a surface ridge across the eastern
portion of the Gulf. Scatterometer data depicts moderate
anticyclonic flow across the eastern Gulf. Little in the way of
any shower activity is noted over the eastern Gulf. However, in
the far western Gulf, SE to S winds have increased to fresh to
strong. Satellite imagery shows higher moisture content and
increasing mid to high clouds over the western Gulf. Scattered
showers are seen west of 95W from 24N-28N.

Fresh to locally strong southerly return flow will increase early
this morning ahead of a cold front, which will move off the Texas
coast by early afternoon today. Strong to near gale force
northerly flow west of the front will increase to gale force
tonight over the northwest and west-central Gulf waters. Near
gale force southerly flow is expected east of the front Thu night
into Fri. Strong to near gale force winds will cover the
Bay of Campeche on Fri. Seas of 12-16 ft will cover a large
portion of the Gulf by Friday behind the front. In addition,
thunderstorms will accompany the front, especially over the
northern half of the Gulf. The pressure gradient will relax on Sat
resulting in moderate to fresh west winds with seas subsiding to
less than 8 ft Sat night.


A weakening stationary front extends from the Windward Passage to
19N80W to 16N85W. Isolated showers are noted along the front.
Scatterometer data from Wednesday evening indicate that a surface
trough is present in the NW Caribbean from 21N82W to 17N85W.
Isolated showers are near the trough south of 20N. In the eastern
Caribbean, radar and satellite imagery show isolated showers from
13N-15N between 67W-71W.

Fresh to strong trade winds will prevail across the south central
Caribbean with nocturnal pulses to near gale force off the
northwest coast of Colombia. These strong trades will expand
north across the entire central Caribbean on Fri and Fri night.
The weak frontal boundary across the west Caribbean will dissipate
early today. The surface trough over the NW Caribbean will move
to the Yucatan Peninsula later this morning. A cold front will
enter the northwest Caribbean on Friday afternoon, and dissipate
over the NW Caribbean during the upcoming weekend. Fresh to strong
winds are expected west of the front on Sat. Large north swell
will reach the Leewards on Sat, and spread south through the
northeast Caribbean passages during the weekend.


A cold front extends from 32N53W to 27N59W to 23N65W, then
continues as a stationary front from that point to the Windward
Passage. Scattered showers are noted along and ahead of the front
north of 30N. To the east, a surface trough is analyzed along 40W
from 17N-24N with isolated showers. A 1029 mb surface high is
centered near 30N28W and extends a ridge across most of the
remainder of the basin.

The front is forecast to drift back north today and extend east to
west along 25N on Fri. Fresh to strong winds will develop along
this boundary as strong high pressure moves east across the
northern waters ahead of the next cold front to enter the NW
waters on Fri night. A strong pressure gradient between this
front and the high pressure will support strong to near gale
southerly return flow north of the Bahamas on Thu night and Fri.
The front is expected to reach from 30N67W to the central Bahamas
on Sun evening and from 30N63W to the southern Bahamas on Mon

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