[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201713
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1213 PM EST Fri Dec 20 2019

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
1700 UTC.

...SPECIAL FEATURES...

A non-tropical area of low pressure is expected to develop over
the north-central Gulf of Mexico on Saturday. This low is
expected to strengthen while it moves northeastward toward the
Florida Big Bend region later in the weekend. Gale force winds are
expected over the NE Gulf waters Sat night. For more details see
the Gulf of Mexico section below and the latest NWS High Seas
Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coast of Liberia near 05N09W
to 04N12W. The ITCZ continues from that point to 02N30W to NE
Brazil near 00N50W. Scattered showers and thunderstorms are seen
within 240 n mi north of the ITCZ between 36W-47W.

GULF OF MEXICO...

A strong 1036 mb surface high over the eastern U.S. is causing
fresh to strong northeasterly to easterly winds across much of the
Gulf of Mexico today. There are a couple of surface troughs, one
over the central Gulf and another over the western Bay of
Campeche that are likely strengthening the winds. Although
infrared satellite images do not show much in the way of deep
convection, there is a considerable amount of cloudiness and
likely isolated to scattered showers across much of the region.
U.S. Doppler radar data indicate that the shower activity is more
concentrated over the far northwestern waters, likely due to the
influence of a subtropical jet. Ship and buoy data indicate that
the seas are highest, from 8 to 11 ft, over the southeastern Gulf
of Mexico where the winds are strongest.

Low pressure is expected to develop over the north-central Gulf
on Sat, then move NE and deepen through Sun night as it crosses
northern Florida. Gale force winds are expected over the NE Gulf
Sat night as the low approaches the Florida Big Bend region. An
associated cold front will sweep across the central and eastern
Gulf this weekend. Strong NW winds will follow the front, with
near gale force winds expected in the far SW Gulf off the coast of
Veracruz. Winds will gradually diminish Mon through Tue night as
high pressure settles over the NW Gulf.

CARIBBEAN SEA...

A surface trough over the Gulf of Honduras is producing an area of
showers and thunderstorms from 16N to 18N between 83W and 88W.
ASCAT scatterometer data indicated that strong westerly winds are
occurring on the south side of the trough along the coast of
Honduras. Similar shower and thunderstorm activity exists over the
southwestern Caribbean Sea from 10N to 13N between 78W and 84W,
primarily associated with the monsoon trough. Elsewhere, generally
quiet weather prevails. The trade wind flow is fresh to strong
across much of the region. Seas are highest near the coast of
Colombia, up to 11 ft, and over the northwestern waters, up to 9
ft.

Strong westerly flow will persist near the coast of
Honduras today as winds funnel between the coastline and a low
pressure trough. High pressure north of the area will maintain
fresh to strong trades and large seas over the central and eastern
Caribbean waters through early next week. Winds near the coast of
Colombia will pulse to near gale force speeds through Sun. A cold
front will cross the Yucatan Channel late Sun, then weaken Mon as
it crosses the NW Caribbean. Fresh to strong northerly winds will
follow the front over the western Caribbean through Tue.

ATLANTIC OCEAN...

A surface cold front extends from 32N47W to 27N59W where it
becomes stationary and extends to central Cuba. Low-level
convergence near the front and an upper-level trough are
producing scattered showers and thunderstorms within 90 n mi of
the stationary front. There are a couple of weak surface troughs
over the western Atlantic, one over the Windward Passage and
another off the northeast Florida coast, but no significant shower
activity is observed near those features. Seas are highest, up to
13 ft, behind the front near the Bahamas where northeasterly
winds are strong. Otherwise, a 1026 mb surface high dominates the
central and eastern Atlantic. This high pressure system and
abundant dry air in the middle and upper-levels of the atmosphere
are producing widespread fair weather across the central and
eastern Atlantic.

The front over the western Atlantic is expected to gradually
weaken this weekend.

$$
Cangialosi
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