[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211802
TWDAT

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 1200 UTC surface analysis and satellite imagery through
1700 UTC.

...SPECIAL FEATURES...

A 1008 mb gale-force non-tropical low is located near 35N60W, or
about 260 nm NE of Bermuda, moving W at 15 kt. Scattered
moderate convection is within 270 nm NE semicircle and 180 nm SW
semicircle. The strongest winds of about 45 kt are located in
the northern semicircle. Any increase in organization would
result in the formation of a subtropical cyclone later today or
tonight as it moves westward to west-southwestward to the
northeast of Bermuda. By Saturday night or Sunday, the low is
forecast to move NE into a more hostile environment. The
potential for subtropical cyclone formation during the next two
days is high. Please see High Seas forecasts issued by the Ocean
Prediction Center at ocean.weather.gov/shtml/NFDHSFAT1.php for
more details on this developing low pressure area.

A 1010 mb well-defined surface low pressure has formed in the
western Gulf of Mexico near 26N94W at 21/1500 UTC and is moving
NNW at 10 kt. A recent ASCAT pass shows winds of 25 kt in the
eastern semicircle of the low. Scattered shower and thunderstorm
activity remains disorganized from 20N-29N between 90W-95W. Any
increase in organized thunderstorm activity near the center
could result in the formation of a short-lived tropical
depression or storm. This system has a medium chance of becoming
a short-lived tropical depression or storm before it moves
inland over the northwestern Gulf coast tonight. Regardless of
development, the system could produce heavy rainfall over
portions of southeastern Texas and southwestern Louisiana
through Saturday, which could lead to flooding across the
region. See the NHC Tropical Weather Outlook at hurricanes.gov
for more information.

Gale Warning for the Canary Islands: According to the forecast
from Meteo France, localized winds to gale force are possible
near and in between the Canary Islands today and tonight. On
Saturday, gale force winds will continue near the Canary
Islands, and gales will expand toward the coast of Morocco,
including the marine zones Agadir and Tarfaya. Outside of the
gales, strong to near gale force winds will cover the area north
of 26N and east of 24W by Saturday. Expect seas to build to
12-14 ft offshore Morocco this weekend, with 9-11 ft seas
elsewhere north of 22N and east of 32W. See the High Seas
Warning and High Seas Forecast products from Meteo France at
weather.gmdss.org/II.html for more details.

...TROPICAL WAVES...

The first tropical wave analyzed in 2021 is located along 44/45W
south of 12N, moving quickly W at 20 kt. The wave is noted in
TPW imagery and NHC's 700 mb diagnostics tool. Scattered
moderate convection is within 120 nm either side of the wave
axis from 03N-07N. The wave could enhance showers over the
southern Windward Islands and SE Caribbean on Sunday.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal border of Guinea
and Guinea-Bissau near 11N15W to 08N19W. The ITCZ continues from
08N19W to 05N27W to 04N42W, then resumes W of a tropical wave
from 03N47W to 03N51W. Isolated moderate convection is noted
along the ITCZ.

GULF OF MEXICO...

See the Special Features section above for information on a
tropical disturbance with a medium chance of formation.

East of 90W, scattered tstorms are noted from 23.5N-26N between
87W-90W. High pressure ridging stretching from the Carolinas to
the NE Gulf of Mexico is leading to mainly clear skies in the NE
corner of the Gulf. The latest ASCAT pass shows fresh to near
gale force E winds covering the eastern and east-central Gulf of
Mexico, where seas are 8-11 ft. NOAA buoy 42003 at 25.9N 85.6W
recently reported a significant wave height of 10.5 ft and E
winds of 25 kt gusting to 31 kt.

A strong ridge stretching from the eastern seaboard to the NE
Gulf will continue to dominate the Gulf waters into Sat night.
The pressure gradient will support fresh to strong SE winds and
high seas across the Gulf region through Sat. Seas of 10 to 11
ft will continue over portions of the east-central and
north-central Gulf through this evening.

CARIBBEAN SEA...

A stationary front extends over the NW Caribbean, south of Cuba,
along 21N. Scattered moderate tstorms are along and south of the
front, from Hispaniola to Jamaica to the Yucatan Channel.
Similar convection is seen over the Gulf of Honduras. Most of
the open waters of the eastern and central Caribbean south of
17N are free of any significant precipitation. The latest ASCAT
pass shows strong E winds south of Cuba, near the stationary
front. Fresh to strong E winds are noted in the central
Caribbean. Moderate wind speeds are closer to Central America,
as well as in the NE corner of the Caribbean. Seas of 6-9 ft
prevail over the central Caribbean, with 4-6 ft seas elsewhere.

For the forecast, high pressure across the western Atlantic will
continue to support fresh to strong winds across the central
Caribbean, and south of Cuba, through Sun morning. A tropical
wave approaching from the east may increase moisture and rain
chances over the southern Windward Islands and SE Caribbean on
Sunday.

ATLANTIC OCEAN...

See the Special Features section above for details on a low
pressure system NE of Bermuda that has a high chance of becoming
a subtropical cyclone.

A cold front extends from 31N58W to 26N65W to 25N70W to 27N74W.
Isolated showers are along the cold front. A stationary front
extends from 31N47W to a 1019 mb low pressure near 29N51W to
26N52W to a 1017 mb low pressure near 24N59W to 20N70W to
21N82W. Scattered showers and isolated tstorms are within 120 nm
of the stationary front. A recent ASCAT pass shows fresh NE
winds in the western Atlantic, between Florida and 70W, with
strong E winds in the Florida Straits. This is due to the
pressure gradient between high pressure over the Carolinas and
low pressure in the western Gulf of Mexico. Seas are 6-8 ft
north of 25N and west of 70W. Wind speeds are gentle to moderate
north of 20N between 30W-65W due to surface ridging that covers
the east-central Atlantic. Seas are 4-6 ft across the
subtropical Atlantic from 19N-27N between 31W-67W. ASCAT shows
fresh to strong winds north of 26N and east of 26W, with
localized areas of near gale to gale force in between the Canary
Islands, where seas are 7-9 ft.

For the forecast west of 65W, the stationary front will slowly
dissipate through tonight. The pressure gradient between high
pressure off the eastern seaboard and the frontal boundary will
support fresh to strong easterly winds N of the front and W of
68W through early Sat. Seas of 6 to 8 ft will prevail across the
region through Sat. Large NE swell will enter the waters from
27N-31N between 65W-75W on Sat, and spread across the forecast
area through Sat night before beginning to subside on Sun.

$$
Hagen
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