[Tropical] Tropical Weather Discussion

Tue Nov 21 00:06:31 CST 2023

AXNT20 KNHC 210606
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Tue Nov 21 2023

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 0000 UTC surface analysis and satellite imagery through
0500 UTC.

...SPECIAL FEATURES...

Atlantic Gale Warning:
A trough of low pressure is developing along a cold front southeast
of Bermuda near 30N59W. It is forecast to move southeastward over the
warmer water of the central subtropical Atlantic, which could
allow this system to gradually deepen over the next few days. As
a result, NW to N winds near this low are going to reach near-gale
to gale force, north of 30N between 57W and 61W later tonight.
Seas in this area will also build to between 13 and 16 ft. These
conditions will shift southeastward along with the low over the
next few days. Since environmental conditions appear to be
conducive for gradual tropical development, this system could
become a subtropical or tropical storm during the latter part of
this week. There is a medium chance of formation for this system
for the next 7 days.

Gulf of Mexico Gale Warning:
A cold front curves southwestward from a 1006 mb low over the
Texas-Louisiana border across Galveston, TX and the northwestern
Gulf to near Brownsville, TX. Scattered heavy showers and strong
thunderstorms capable of producing dangerous lightnings and gusty
winds are occurring near and up to 120 nm east of this boundary.
It will gradually move southeastward over the next few days,
reaching from near New Orleans, LO to near Veracruz, Mexico this
afternoon. Northerly winds behind this front will reach near- gale
force across the northwestern and west- central Gulf, and gale
force at the western Bay of Campeche near Veracruz by noon Tue.
Seas will peak from 8 to 12 ft across the northwestern and west-
central Gulf, and 11 to 14 ft at the western Bay of Campeche.
Once the front has pushed farther east from the Florida Big Bend
area to the eastern Bay of Campeche on Wed, both winds and seas
should gradually subside across the western Gulf.

Please read the latest High Seas Forecast, issued by the National
Hurricane Center at the website -
www.nhc.noaa.gov/text/MIAHSFAT2.shtml, and the latest Offshore
Waters Forecast to the west of 55W, at
www.nhc.noaa.gov/marine/offshores.php for details on both Gale
Warnings.

...MONSOON TROUGH/ITCZ...

The monsoon trough remains over the Africa continent. An ITCZ
extends west-southwestward from west of Guinea at 08N16W across
05N30W to 05N40W. Widely scattered moderate convection is noted
near and up to 150 nm north of this feature.

...GULF OF MEXICO...

Please read the Special Features section about a Gale Warning in
southwestern Gulf.

Besides the cold front and its related weather mentioned in the
Special Features section, a broad surface ridge extends
southwestward from northern Florida to south of Tampico, Mexico.
Fresh with locally strong winds are from the NW at the
northwestern edge of the Gulf, and from the SE near the Florida
Panhandle. Seas at both areas are from 4 to 7 ft. Gentle to
moderate with locally fresh SE to SW winds and seas of 2 to 5 ft
prevail for the rest of the Gulf.

For the forecast, the aforementioned cold front will reach from
Tampa Bay to the eastern Bay of Campeche Wed afternoon. Strong to
severe thunderstorms, with locally high winds and seas, will be
along and just ahead of the cold front through Tue for areas north
of 28N. Read the Special Features section for developing gales and
building seas behind this front. Winds and seas will subside late
Wed into Thu as high pressure settles in.

...CARIBBEAN SEA...

The dissipating portion of a cold front reaches westward from
Hispaniola to west of Jamaica. Widely scattered showers are seen
near this boundary. The eastern end of the East Pacific monsoon
trough stretches eastward from near the Nicaragua-Costa Rica
border to a 1008 mb low north of Colombia-Venezuela border.
Isolated thunderstorms are noted near the monsoon trough, while
scattered showers and isolated thunderstorms are occurring near
and east of the low. Moderate with locally fresh ENE to ESE winds
and seas of 3 to 5 ft are present at the northwestern and north-
central basin, including the Mona Passage. Gentle to moderate NE
to SE winds and 2 to 3 ft seas prevail elsewhere in the Caribbean
Sea.

For the forecast, nearby dry air is forecast to prevent additional
development for the 1008 mb low north of Colombia as it drifts
slowly westward over the next couple of days. Meanwhile, high
pressure building toward the Greater Antilles is leading to
moderate to fresh NE winds in the Windward Passage and just south
of Hispaniola. These winds will increase further to locally strong
Tue into Wed. Elsewhere, winds will be moderate or less into late
week.

...ATLANTIC OCEAN...

Please refer to the Special Features section at the beginning for
detail on a Gale Warning.

A cold front curves southwestward from a 1005 mb low east of
Bermuda across 31N58W to near Hispaniola. Convergent southerly
winds east of the front are triggering scattered moderate
convection north of 23N between 52W and 58W. At the central and
eastern Atlantic, a stationary front curves southwestward from
near the Azores across 31N25W to 21N36W, then continues westward
to 22N43W. Widely scattered to scattered moderate convection is
evident near and up to 80 nm southeast and south of this feature.
Convergent trade winds are causing widely scattered moderate
convection from 07N to 10N between 34W to 48W. Aided by strong
divergent flow aloft and abundant moisture, a surface trough is
producing scattered showers and isolated thunderstorms from 08N to
20N between 19W and 30W, including the Cabo Verde Islands. Refer
to the Monsoon Trough/ITCZ section for additional weather in the
Atlantic Basin.

Outside the Gale Warning area, fresh to strong SW to NW winds and
seas of 8 to 12 ft are found near the cold front from 25N to 30N
between 52W and 68W. To the west, moderate to fresh NE to to ESE
winds and 6 to 9 ft seas in large NE swell are evident north of
20N between 68W and the Georgia-Florida coast. For the central and
eastern Atlantic, gentle to moderate with locally fresh NE to SE
winds and 6 to 9 ft seas in moderate northerly swell exist north
of 20N between the Africa coast and 52W, including the Canary
Islands. Near the Cabo Verde Islands, light to gentle with locally
moderate easterly winds and seas at 5 to 8 ft are seen from 07N to
20N between 20W and 35W. Further west, gentle with locally
moderate ENE to SE winds and seas of 5 to 7 ft dominate from the
Equator to 20N/25N between 35W and the Lesser Antilles. Light to
gentle southerly winds and 4 to 7 ft seas in mixed swells prevail
for the remainder of the Atlantic Basin.

For the forecast west of 55W, the aforementioned developing low
southeast of Bermuda in the Special Features section will cause a
broad area of strong winds on both sides of the front north of
23N and east of 65W. Very rough seas of up to 20 ft will accompany
this area of strong to gale-force winds. Regardless of
developments, northerly swell will lead to seas of 12 ft or
greater east of 65W and north of 20N by mid through late week.
Looking ahead, fresh to strong winds will develop offshore
northern Florida by Wednesday in advance of the next cold front.

$$

Chan
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