[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 141035
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Mon Dec 14 2020

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 0600 UTC surface analysis and satellite imagery through
0940 UTC.

...SPECIAL FEATURES...

Gulf of Mexico Gale Warning: A strong cold front has blasted
across the NW Gulf overnight and extends from SE Louisiana near
30N89.5W to 27.5N90.5W to just south of Tampico, Mexico. Overnight
surface observations and ASCAT data indicate that gale force NW
to N winds are occurring in a band within 90 nm behind the front,
from the SE Louisiana coast to Mexico. The gales will spread
southward through the western Gulf, affecting the waters off
Tampico early this morning, then shift southward to offshore
Veracruz late morning through afternoon. Winds will diminish to
below gale force in the NW Gulf by late this morning, and in the
southwest Gulf by late afternoon. Seas as high as 13 ft are
expected today over portions of the western Gulf. The front is
expected to reach from near Port Charlotte, FL to the eastern Bay
of Campeche by this evening then move more slowly southward
through Tue. Winds and seas will decrease quickly Mon night
through Tue as high pressure moves over the area and the front
weakens across the southern Gulf. Please read the latest High Seas
Forecast at https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for
more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends from the coast of Sierra Leone
near 09.5N13W to 05N23W. The ITCZ is from 05N23W to 04N34W to
01N47W. Scattered moderate to strong convection is from 03N-08N
between 08W-37N. Scattered moderate isolated strong convection is
noted from 02N-09N between 37W-51W, and from 06.5N-12.5N between
50W and 61W

GULF OF MEXICO...

A strong cold front extends southwestward across the Gulf of
Mexico from SE Louisiana near 30N89.5W to just south of Tampico,
Mexico near 22N98W. Gales are occurring over the NW Gulf behind
the front. Please see the Special Features section above for
details on the Gale Warning in the western Gulf of Mexico. Ahead
of the front strong SW winds prevail across the coastal waters
from the mouth of the Mississippi River to near Apalachicola,
Florida. Scattered showers are seen on a 30 nm wide fine line
along the front. A pre-frontal trough extends from the Florida Big
Bend southwest to 26N87W, where scattered showers and isolated
thunderstorms are seen along the trough.

The cold front will cross much of the Gulf today, reaching SW
Florida to the eastern Bay of Campeche, then move slowly
southward tonight and Tue and across the far SE Gulf. Another cold
front will move into the NW Gulf Tue night and cross the basin by
Thu. This front will bring brief gales offshore Veracruz on Wed.

CARIBBEAN SEA...

Mid to upper-level ridging covers the western Caribbean west of
70W. An upper-level trough axis extends from the Atlantic near
28N55W to the eastern Caribbean. GOES-16 water vapor channels
indicate that dry air covers nearly the entire basin. As a
result, there are no significant areas of precipitation noted.
Overnight ASCAT data reveal fresh trades over the central part of
the Caribbean between 68W-79W, with strong trades off the coast
of Colombia and NW Venezuela south of 13N between 70W-77W. Gentle
to moderate trades are elsewhere across the sea. Seas of 6-9 ft
are over the south-central Caribbean, while the rest of the basin
in averaging seas of 3-5 ft.

Strong NE to E winds this morning offshore of Colombia will
diminish this afternoon as high pressure weakens early this week,
and winds and seas subside modestly basin wide. By Thursday, the
high will re-strengthen to the north or the area, and strong
nightly pulses will redevelop offshore of Colombia. A weakening
cold front will move slowly SE across the Yucatan Channel and
western Cuba late Thu through Fri.

ATLANTIC OCEAN...

A broad surface ridge extends WSW from a 1028 mb high near 34N47W
to Bermuda to north Florida. Over the central Atlantic, an upper-
level trough axis extends from 30N54W to the NE Caribbean. A
surface trough lies underneath the upper-level trough and extends
from 27N58W to a weak 1015 mb low near 23N57W to 18N58W. The
pressure gradient between the high and the weak low is producing a
zone of strong E to SE winds to the north and northeast of the
surface low, and is helping to promote scattered moderate showers
and isolated tstorms from 16N-25N between 48W-57W. A cold front
is from 32N19W to 27N36W. A shear line continues from 27N36W to
25N56W. Strong E winds are seen north of the shear line to 30N
between 43W-55W. Seas of 9-12 ft are east of 50W and north of 25N
due to waves generated by the strong easterly winds and large N
swell dominated the Atlantic east of 70W. This swell is forecast
to gradually subside today into Tue.

A deep layer trough will remain nearly stationary along about
57W/58W through Tue. Strong SW winds will develop N of about 28N
this morning ahead of a cold front that will move off the Florida
coast this evening. This front will drag across the northern
waters through Wed. The next cold front will move into the NW
waters Wed night then slide slowly SE and reach from near Bermuda
through the NW Bahamas to W Cuba Fri morning.

$$
Stripling
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