[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 091705
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Fri Dec 9 2022

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...

Central Atlantic Gale Warning: A deepening 968 mb non-tropical
low pressure system is located near 34.5N40.5W. An area of
scattered moderate convection is observed north of 18N, between
20W and 46W. A very large area of gale force winds are observed
in this mornings scatterometer pass north of 22N between 33W and
43W. Very rough to high seas cover an extensive area north of 15N,
between 27W and 70W. Conditions will gradually improve today in
the subtropical Atlantic as the low moves quickly NE. However,
seas will remain very rough north of 25N through the weekend.
Large, long-period N to NE swell will impact the Atlantic waters
and Caribbean Passages between the southeastern Bahamas and the E
Caribbean producing high seas into the start of next week, with
large E swell reaching the Florida offshore waters N of 26N early
Fri through Sat.

Central Atlantic Gale Warning: A new low will develop
along 65W and N of 31N by late Sat and move SSE entering the
central Atlantic this weekend. Gale-force winds will develop near
the low along 28N. These conditions will dissipate by early next
week as the low moves quickly E while weakening.

More information about these systems, including the associated
Storm and Gale Warnings, can be found in the High Seas Forecasts
issued by the National Hurricane Center at
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic waters from the coast of
Guinea near 11N15W and extends to 08N17W. The ITCZ continues from
08N17W to 03N46W. Scattered showers are noted along the ITCZ from
01N to 08N between 34W and 43W.

...GULF OF MEXICO...

A surface trough is analyzed in the southwest Gulf from 23N91W to
19N94W. Weak convection is observed on satellite west of the
trough, south of 20N to near Veracruz, Mexico. Across the
remainder of the basin, a 1021 mb surface high centered near
28N91W is supporting generally fair weather conditions and mainly
gentle to moderate easterly winds. Seas remain 1 to 4 ft over the
majority of the basin, with 3 to 5 ft seas S of 25N including the
Yucatan Channel.

For the forecast, the 1021 mb high will meander through the
weekend, then shift eastward early next week as a cold front
approaches the NW Gulf. Gentle to moderate winds will prevail
through the weekend, increasing to moderate to fresh early next
week. Winds may increase to strong speeds and seas build up to 8
ft late Tue in the NW Gulf as the aforementioned front approaches
from the NW.

...CARIBBEAN SEA...

The pressure gradient between subtropical high pressure in the
western Atlantic and lower pressure over Colombia is generating
moderate to fresh NE winds west of 70W in Caribbean, including
the Windward Passage, where seas are in the 6 to 8 ft range. A
recent scatterometer pass reveals locally strong NE winds off NW
Colombia. In the E Caribbean, gentle to moderate N winds prevail
with mainly 4 to 6 ft seas. Seas are 8 to 12 ft near and SW of
Atlantic passages due to long period NE swell originating from the
gale force low in the central Atlantic.

For the forecast, the strengthening non-tropical low pressure
system in the central Atlantic is accelerating northward and
gradually moving away from the forecast area. Large NE swell
across the central Atlantic will move through the Caribbean
Passages and Tropical Atlantic waters through late Sat, decreasing
on Sun and increasing again early next week as another swell
event reaches the region. High pressure over the Gulf of Mexico
extends southeastward, sustaining NE-E winds across much of the
forecast waters. Fresh to strong pulsing NE-E winds will occur in
offshore Colombia into early next week. Moderate to fresh NE
winds, occasionally pulsing to strong speeds, will affect the
Caribbean Passages and the lees of the Greater Antilles through
tonight.

...ATLANTIC OCEAN...

Please read the Special Features section above for details on the
Gale Warnings active in the basin.

Elsewhere, a weak cold front extends across the western Atlantic
from 31N64W to 29N70W to 31N75W. No notable convection is
associated with this front. South of the front, a weak high
pressure ridge off NE Florida is supporting gentle winds and 4-6
ft seas in the far western Atlantic. In the far eastern Atlantic,
gentle to moderate anticyclonic flow with seas of 5 to 7 feet
prevail. Otherwise, the remainder of the basin moderate or weaker
winds and moderate seas prevail.

For the forecast W of 55W, the deepening low pressure system over
the central Atlantic is accelerating northward into the north
Atlantic and forecast to strengthen into a powerful non-tropical
cyclone. Large long-period north to northeast swell will impact
the Atlantic waters and Caribbean Passages between the
southeastern Bahamas and the E Caribbean, producing high seas into
the start of next week, with large E swell reaching the Florida
offshore waters N of 26N through Sat. A new low will develop along
65W and N of 31N by late Sat and move SE entering the central
Atlantic this weekend. Gale-force winds will develop along 28N.
These conditions will dissipate by early next week as the low
moves quickly E while weakening.

$$

Nepaul
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