[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231804
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Sat Jan 23 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 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.

...SPECIAL FEATURES...

Caribbean Gale Warning: The combination of a 1019 mb high center
over the Atlantic near 23N69W north of Puerto Rico and low
pressure over northern Colombia is resulting in a tight pressure
gradient in the south-central Caribbean. This will again lead to
northeast to east winds to pulse to gale force tonight and into
early on Sun along and near the coast of Colombia. This favorable
synoptic pattern setup will continue to promote this pulsing of
winds to gale force well into next week. Wave heights generated by
these winds are forecast to be in the range of 8-12 ft, mainly
around daybreak each day. Please read the latest NWS High Seas
Forecast issued by the National Hurricane Center at the website
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details.

...MONSOON TROUGH/ITCZ...

A rather short monsoon trough axis extends from the coast of
Africa at the Cote d'Ivoire and Liberia border near 04N08W to
05N15W, where morning ASCAT data indicates that it transitions
to the ITCZ to 03N29W to 03N38W and to near 03N47W. Scattered
moderate to isolated strong convection is seen within 120 nm
north of the ITCZ between 26W-31W. Scattered moderate convection
is within 240 nm south of the monsoon trough between 16W-19W and
between 31W-35W. Similar activity is within 60 nm north of the
monsoon trough between 13W-19W and between 31W-35W. Other
scattered moderate convection is within 30 nm either side of a
line from 04N45W to near the coast of northern Brazil at 04N51W.


GULF OF MEXICO...

Patchy to areas of dense fog is noted across portions of the Gulf
coastal waters early this morning, with the potential for
visibilities to be reduced to 1 nm or less. This fog should
diminish by late morning. Otherwise, fair conditions are noted
across the basin.

As of 15Z, a stationary front extends from north-central Florida
to 29N90W and to inland Texas near Corpus Christi. A far western
Gulf trough extends from just south of the stationary front near
28N94W to 26N96W and to 23N97W. As of 15Z, a 1020 mb high is
centered over the far southeastern Gulf at 25N82W. High pressure
is present across the rest of the area, with stronger high
pressure analyzed over far NE Gulf. Latest buoy data indicates
light to gentle anticyclonic wind speeds south of the
aforementioned stationary front due to the 1020 mb high center.
The latest buoy data along with overnight ASCAT confirm that
gentle to moderate northeast to east winds are north of the
aforementioned frontal boundary. Satellite imagery shows overcast
low and mid-level clouds, with possible patches of mainly light
rain and scattered light showers to be confined along and within
120 nm north of the frontal boundary. Patches of stratus-type
clouds and fog are advecting northward over the far western Gulf
from 21N- 25N and between 93W-97W.

The cold front will become stationary by late this afternoon or
early this evening, while the stationary front will begin to lift
northward as a warm front this afternoon through Sun. Patchy to
widespread areas of dense fog, with visibilities reduced to 1 nm
or less are likely to develop again during the overnight hours
and into Sun morning over the Gulf coastal plains as well as over
and along the Florida west coast north of about Naples. High
pressure will build over the southeastern United States, with
increasing southerly return flow and building seas Sun through
Mon. The high pressure will weaken late Mon as a weak cold front
moves into the western Gulf and becomes stationary by early Tue.
The front will then get reinforced and progress eastward across
the basin through Fri.

CARIBBEAN SEA...

Refer to the Special Features section above for details on an
ongoing Gale Warning in the south-central Caribbean northwest of
the coast of Colombia.

Elsewhere, mainly gentle to moderate trades prevail, except
moderate to fresh trades in the central Caribbean. Seas are 3 ft
or less in the northwest Caribbean, and mainly 4-7 ft elsewhere.
Satellite imagery reveals patches of low-level clouds moving
westward in the trade wind flow. Isolated showers are possible
with some of these clouds. Scattered showers and isolated
thunderstorms are over southern Panama, but appear to be weakening
during the past few hours. Otherwise, no significant convection
is noted over the Caribbean waters, over the islands and nearby
land areas.

Mainly moderate to fresh trades will prevail through the next
several days outside of the south-central Caribbean, pulsing to
fresh to strong over the Gulf of Honduras on Mon through Wed.
A north well will propagate into the Tropical North Atlantic
waters from Mon night through Thu. A cold front is likely to
enter the Yucatan Channel from the northwest Thu night.

ATLANTIC OCEAN...

West of 55W, a 1019 mb high pressure center is analyzed  east of
the southern Bahamas and Turks and Caicos near 23N69W, with a
ridge axis extending west-northwestward to a 1020 mb high center
that is over the far southeastern Gulf of Mexico at 25N82W. A cold
front extends along a position from near 32N58W to 28N70W and to
inland Florida near Daytona Beach. Satellite imagery shows broken
to overcast low and mid-level clouds, with embedded patches of
rain and possible scattered showers along and north of the front
to near 31N. Fresh to strong southwest winds are occurring north
of 27N and east of the front, with mainly gentle to moderate winds
elsewhere. A set of large northerly swell with seas of 8-11 ft
associated with the frontal system extend across the waters north
of 27N and east of 70W, with 3-6 ft seas noted elsewhere outside
of the Bahamas, except 4-7 ft east of 70W.

The cold front will reach along 26N by this evening, while a
reinforcing cold front merges with it along 25N by Sun morning.
The merged front will stall along 21N north of the coast of the
Dominican Republic by Mon afternoon and dissipate on Tue. A new
cold front will move across the northern waters Tue night shifting
south while weakening through early Thu. Another stronger cold
front may move off the southeast United States coast by Thu
afternoon while parent low pressure rapidly intensifies north of
the area through the end of the week. Gale force winds and very
large seas are possible with this system, with storm force to near
hurricane force winds possible north of 32N.

East of 55W, a cold front extends from a 1009 mb low north of the
area near 38N38W through 32N38W and to 28N40W, where it becomes a
weakening stationary front to 27N45W and to near 25N50W. An
upper-level disturbance diving southeastward is behind the front
near 30N47W. Scattered moderate convection is within 60 nm of this
disturbance. Scattered showers are possible near and along the
front north of 28N, while isolated showers are possible along and
near the stationary front. Fresh to strong south winds are within
150 nm east of the front north of about 28N,  while northerly
swell of 7-11 ft covers the waters north of 20N, except 11-14 ft
north of 27N between 37W-50W. A 1027 mb high pressure center
is centered near 32N18W with a ridge axis reaching from the high
west-southwestward through 26N37W and to near 22N53W. Moderate to
fresh trades cover the waters south of 20N, with gentle to
moderate trades found near the ridge. Seas of 6-9 ft in mainly
fresh trade wind swell dominate the open waters of the tropical
Atlantic.

$$
Aguirre
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