[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211016
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Tue Dec 21 2021

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 31N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 0600 UTC surface analysis and satellite imagery through
1000 UTC.

...SPECIAL FEATURES...

.GULF OF MEXICO GALE WARNING...

An extratropical low pressure of 1008 mb located near 26N86W is
strengthening it moves NE through the NE Gulf. Overnight
scatterometer data indicated a wide area of strong cyclonic winds
in the vicinity of the low, with a smaller area of gale force
winds to 40 kt within about 90 nm of the center in the N
semicircle. These gales will progress as the low moves toward the
Florida coast, and will end around midday as the low moves inland
and away from the area. Seas through the day will be 8 to 11 ft.
Conditions will begin to improve late today.  Please refer to the
latest High Seas Forecast, issued by the National Hurricane
Centered the following website:
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml, for more details.

.ATLANTIC GALE WARNING...

Low pressure will track across Florida later today and then
northeastward into the Atlantic this evening. As it does, westerly
winds will increase over Atlantic waters, with gales developing N
of 28N and W of 71W this evening and continuing into at least
early Wed. As the low accelerates northeast, farther away from
the area, Wed, conditions will slowly improve. Seas in and near
the gale area will increase to 10 to 14 ft Tue night and continue
through Wed. Please refer to the latest High Seas Forecast issued
by the National Hurricane Center, at the following website:

https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml, for more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the Prime Meridian at 02N and
continues to around 02N02W. The ITCZ continues from 02N02W to
03N07W to 03N22W to 01N47W. Scattered moderate convection is noted
from 03N to 14N between 13W and 27W as well as within 270 nm N of
the ITCZ between 35W and 41W.

...GULF OF MEXICO...

Please see the Special Features section above for details about a
low pressure in the NE Gulf producing gale conditions this
morning.

A large area of numerous moderate to scattered strong convection
is noted in association with this low pressure, from 26N to 31N
between 83W and 86W. In addition, a cold front trails southward
from the low, stretching from 26N86W to the Yucatan Channel.
Scattered moderate to isolated strong convection is also present
in advance of this cold front, extending as far east as 82W.
Finally, a slow-moving warm front extends east from the low to
near Fort Myers, Florida. As the low and cold front progress east
and northeast this morning, the potential for strong to severe
thunderstorms exists over the far eastern Gulf of Mexico.

Farther west, high pressure of 1022 mb, centered offshore Tampico,
Mexico, is building SE into the Gulf. Outside of the winds in
direct association with the low pressure, fresh NW winds dominate
the basin, with an area of strong NW occurring just offshore
Veracruz, Mexico. Ahead of the cold front in the far SE basin,
including the Florida Straits, winds are moderate to fresh out of
the SW. Seas of 8 to 11 ft extent across a broad area of the Gulf,
stretching from the Bay of Campeche and SW Gulf, through the
central Gulf, and into the NE Gulf. Seas are likely higher near
the most robust convection in the NE basin. In the NW Gulf, seas
of 5 to 7 ft are present, with seas of 4 to 6 ft occurring to the
east of the cold front in the far SE Gulf.

For the forecast, the aforementioned low pressure will track NE
and move inland into Florida by midday, ending gales for the NE
Gulf of Mexico, with the cold front moving SE of the Gulf by this
evening. Fresh to strong winds and seas of 8 to 10 ft behind the
front will gradually subside Wed. High pressure crossing the
northern Gulf will lead to tranquil conditions Wed night through
Thu, but by Fri and into the weekend, fresh to possibly locally
strong return S flow will develop in the western Gulf.

...CARIBBEAN SEA...

Most of the basin is void of convection, but a band of scattered
moderate thunderstorms extents within about 60 nm of a cold front
that is crossing the Yucatan Channel and extends SW along the
coast of the Yucatan Peninsula. Convection previously associated
with the eastern extension of the East Pacific monsoon trough in
the far SW Caribbean has diminished and moved inland over Panama
and portions of Colombia.

With the cold front approaching the basin, the pressure gradient
between higher pressure to the north and lower pressure over South
American has been disrupted and relaxed. This has allowed for
trades to diminish some overnight, and now moderate trades
dominate the central and eastern basin, with light to gentle winds
in the west. Seas range from 3 to 6 ft in the central, east, and
southwest, with heights averaging 1 to 3 ft in the NW.

For the forecast, a cold front will move into the NW Caribbean today,
then gradually stall from the Windward Passage to offshore
Nicaragua for the latter part the week. Fresh N winds can be
expected behind the front. Otherwise, a relatively weak pressure
gradient will lead to diminished trades much of the week, with
generally moderate E wind expected.

...ATLANTIC OCEAN...

Please see Special Features section above for information on gales
that will occurring later today and tonight in association with a
low pressure that will move NE off the NE Florida coast.

A cold front stretches from 31N50W to 27N70W, then transitions to
a slow moving warm front that continues to near West Palm Beach,
Florida. Scattered convection has developed N of this warm front,
offshore within about 120 nm of the Florida coast. Otherwise, most
precipitation associated with this frontal boundary is well N of
31N, E of 50W. N of 28N, ahead of the front to the E of 50W, fresh
to strong SW winds are occurring, with fresh to locally strong NE
winds to the N and W of the boundary, also N of 28N. Seas of 8 to
10 ft are also occurring in and near this area of higher winds,
although most of the wave height is deriving from long period
northerly swell.

Most of the rest of the basin is dry, dominated by a weakening
1020 mb high pressure center near 25N48W. To the south of this
high, the gradient between it and the ITCZ is inducing fresh to
strong trades, leading to seas of 8 to 11 ft. Along and to the
north of the high, to near 28N, winds are moderate or less and
seas are 6 ft or less.

For the forecast, in advance of low pressure, a warm front will
lift northward out of the region today. The low will then move NE
to the north of the area late today and tonight, with gale force
winds developing on both sides of it for areas N of 28N and W of
71W. A trailing cold front will cross the region Wed through Thu,
bringing scattered showers and thunderstorms with it. Building
high pressure behind the low should lead toward tranquil
conditions Thu night through Fri.

$$
KONARIK
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