[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 111806
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Fri Dec 11 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 1200 UTC surface analysis and satellite imagery through
1745 UTC.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends from the coast of Sierra Leone at
09N13W to 07N15W, where latest scatterometer data indicates that
it transitions to the ITCZ to 04N27W and to 04N44W. Scattered
moderate to isolated strong convection is seen within 120 nm
north of the trough axis between 15W-18W. Scattered moderate
convection is within 210 nm north of the ITCZ between 28W-32W,
within 60 nm south of the trough axis between 15W-18W and also
between 26W-28W and between 28W-31W.

GULF OF MEXICO...

Broad upper-level anticyclonic flow covers the basin, with the
associated ridge axis extending from 32N88W to the Yucatan
Peninsula. Associated table sinking air covers the far eastern
section of the Gulf. A high pressure center of 1023 mb is centered
over north-central florida with a ridge extending west-
southwestward to 27N87W and to near 26N92W. A surface trough
extends along the Mexican coast from near Tampico south-
southeastward along the coast to near Veracruz. Fresh to locally
strong southerly winds prevail across the western Gulf west of
94W, from near Veracruz to the central Texas coast. Seas are
in the range of 4-7 ft across the Gulf, except for lower seas
of 3-4 ft in the eastern and central Gulf.

As for the forecast: The high pressure center over north-central
Florida will shift northeastward through Friday, allowing fresh
to locally strong southerly winds to expand across the western
Gulf of Mexico in advance of the next approaching cold front. This
front will move into the NW Gulf late Sun, then extend from the
Florida panhandle to the Bay of Campeche Mon. Strong northwest to
north winds will follow in behind the front. Gale conditions are
likely Mon night offshore Mexico from Tampico to Veracruz.

CARIBBEAN SEA...

The previous analyzed stationary front that was analyzed across
the central Caribbean has dissipated. A tight enough gradient in
place is allowing for mainly fresh northeast winds to exist over
the northwestern and western Caribbean waters. Fresh to strong
northeast winds, as were highlighted by a morning ASCAT pass, are
over the far south-central Caribbean to along the coast of
Colombia. These winds will pulse at night through early next week.
Gentle to moderate trades exist elsewhere across the basin. Seas
are in the range of 4-7 ft, except for higher seas of 6-9 ft in
the far south-central Caribbean to near the coast of Colombia.

Broken to overcast low and mid-level clouds with isolated showers
are seen across the Windward Passage and within 210 nm of the
coasts of Nicaragua and Costa Rica. Similar clouds with isolated
showers are over eastern Honduras and over the northern and
central sections of Nicaragua. Scattered to broken low and mid-
level clouds are over the majority of the island of Hispaniola.
Scattered showers and isolated thunderstorms are possible with
these clouds. Otherwise, patches of broken low and mid-level
clouds with isolated showers are moving westward in the trade wind
flow north of 15N and also south of 15N between 64W-69W.

As for the forecast: Weak high pressure will remain over the
area well into next week. Weakening high pressure across the
western Atlantic Mon and Tue will induce a considerable
diminishing of winds and seas area wide.

ATLANTIC OCEAN...

A weakening cold front extends from near 32N47W to 27N52W, then
transitions to a stationary front to Hispaniola near 19N70W.
Two broad surface ridges are on either side of this frontal
system. Scattered moderate convection is seen within 90 nm SE of
the front between 56W an 66W, while scattered moderate isolated
strong convection is within 240 nm SE of the front to the north of
24N. Deep-layer low pressure centered near 22N44W is supporting
scattered moderate convection from 18N to 24N between 42W and 48W.
Elsewhere, a broad surface ridge is centered on a 1030 mb high
near 33N26W, while a ridge west of the front is centered on a
1026 mb high near 36N70W. A weak trough is just along the Florida
coast from near 28N80W to 26N80W. Isolated showers are near it.

As for the forecast: The weakening stationary will dissipate
tonight. A high pressure ridge will dominate waters north of this
front, bringing fresh to strong northeast to east winds across
northern waters this weekend. A cold front will move off the
FLorida coast Mon night, with some strong southwest winds ahead
of the front, mainly N of 27N.

$$
Aguirre
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