[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 151758
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Wed Mar 15 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 1200 UTC surface analysis and satellite imagery through
1630 UTC.

...SPECIAL FEATURES...

Atlantic Gale Warning: A cold front extends from east of Bermuda
across 31N57W to 25N71W, then continues as a stationary front
across the Central Bahamas to beyond northwestern Cuba. This
whole boundary should become a cold front this evening and move
southeastward across the Greater Antilles through Fri morning. It
will produce strong to gale force westerly winds northeast of the
southeast Bahamas near 23N68W Thu morning, and then north and
northeast of Puerto Rico near 22N64W Thu afternoon, and finally
well northeast of the Leeward Islands near 22N59W Thu evening.
Seas are expected to peak between 11 and 13 ft under the strongest
winds. Conditions should gradually improve early Fri morning
through Fri afternoon.

Atlantic Significant Swell Event: Satellite altimeter data this
morning revealed 10 to 12 ft seas southwest Bermuda near 13N67W,
produced by large NW to N swell behind the aforementioned cold
front. As this swell sinks farther southeastward through Fri, seas
will build further to between 12 and 15 ft north of 22N between
38W and 73W. Seas should gradually subside starting Sat morning as
the swell decreases.

Please read the latest High Seas Forecast at
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and Offshore Waters
Forecast at https://www.nhc.noaa.gov/marine/offshores.php for
more details on these events.

...MONSOON TROUGH/ITCZ...

A monsoon trough enters the Atlantic through the African coast
near St Louis, Senegal then continues westward to near the Cabo
Verde Islands. No significant convection is seen near this
feature. An ITCZ extends from southwest of Sierra Leone near
05N14W across 02N30W to north of Belem, Brazil near 02N48W.
Scattered moderate to isolated strong convection is noted from
the Equator to 07N between the Sierra Leone/Liberia and Brazil
coasts.

...GULF OF MEXICO...

A stationary front extends west-southwestward from the central
Bahamas across the Florida Straits to just northwest of the
Yucatan Peninsula. Scattered showers and thunderstorms are
occurring along and up to 60 nm north of this boundary. Convergent
SE winds are causing similar conditions at the western edge of the
Gulf, along the Mexican coast. Otherwise, a surface ridge
extending southwestward from a 1028 mb high over Alabama to near
Tampico, Mexico continues to dominate the northern and central
Gulf. Gentle to moderate ENE to ESE winds and seas at 3 to 5 ft
are present across the northern Gulf and western Bay of Campeche.
Moderate to fresh NE to ENE winds with 5 to 7 ft seas are evident
for the south-central and southeastern Gulf, including the eastern
Bay of Campeche and Florida Straits.

For the forecast, the stationary front is being reinforced by a
surge of fresh to strong NE winds today, which should transform
it back to a cold front later this afternoon. It will then move
southward out of the Gulf by this evening. In response, return
flow will develop across the western Gulf tonight, become fresh
to strong early Thu and spread across the entire Gulf Thu night,
ahead of the next cold front. This second front will move into
the northwestern Gulf Fri morning, reaching from Apalachee Bay,
Florida to the central Bay of Campeche Sat morning. Brief gale-
force N winds are expected behind the front offshore of the upper
Mexican waters late Fri afternoon, shifting to offshore Veracruz
Fri evening and night.

...CARIBBEAN SEA...

A surface ridge associated with a 1021 mb high at the central
Atlantic near 28N45W continue to maintain a trade-wind regime
across the basin. Two surface troughs at the Gulf of Honduras and
over eastern Cuba and Jamaica are generating scattered showers and
isolated thunderstorms at the northwestern and north-central basin.
Fresh to locally strong easterly winds and seas at 5 to 7 ft are
present at the south-central basin. Moderate to fresh E to ESE
winds with 4 to 6 ft seas are found at the eastern and north-
central basin. Gentle to moderate easterly winds and seas of 2 to
4 ft prevail for the rest of the basin.

For the forecast, the surface ridge will shift northeastward
through the rest of the week as a cold front sinks slowly
southeastward across the northwestern basin this evening. The
front will reach from the Windward Passage to Belize on Thu, and
then from the northern Leeward Islands to the central Caribbean
along 17N Fri. Strong winds will follow the front, especially in
Atlantic passages along with large N swell spreading through
Atlantic passages early Fri through Sat. Another front is expected
to stall near or just north of the Yucatan Channel by Sun.

...ATLANTIC OCEAN...

Please read the Special Features section at the beginning for more
information about upcoming gales and large swell.

A cold front extends from east of Bermuda across 31N57W to
25N71W, then continues as a stationary front across the Central
Bahamas to beyond northwestern Cuba. Scattered showers and
thunderstorms are occurring near and up to 70 nm northwest of
this boundary. Another weak cold front reaches southwestward from
southeast of the Azores across 31N26W to 23N41W. Patchy showers
are seen near and up to 70 nm northwest of this front. Convergent
trade winds are causing scattered showers near Puerto Rico and
the Virgin Islands.

A surface ridge stretches southwestward from a 1021 mb high near
28N45W to near Hispaniola. Light to gentle winds with 7 to 10 ft
seas in northerly swell exist near these features and the weak
cold front north of 20N between 27W and 59W. To the west, moderate
to fresh with locally strong SW to NNW winds and seas at 8 to 12
ft are seen near and behind the cold front between 59W and the
Georgia/Florida coast. Near the Canary Islands, moderate to fresh
NNE trades and seas of 6 to 8 ft are noted north of 19N between
the northwest African coast and 27W. To the south, gentle to
moderate northerly winds with 4 to 6 ft seas are seen from 10N to
19N between the central African coast and 35W. Farther west,
gentle to moderate with locally fresh NE trades and seas of 6 to 9
ft in moderate northerly swell exist from 06N to 20N between 35W
and the Lesser Antilles. Light to gentle winds along with 4 to 6
ft seas prevail for the remainder of the Atlantic Basin.

For the forecast W of 55W, the cold/stationary front will move
southeastward and reach from near 30N55W to the Windward Passage
Thu morning, and from 20N55W through the Leeward Islands by Fri
morning. Other than gale-force winds mentioned in the Special
Features section, strong to near-gale force NW winds immediately
behind the front will move through the Central and southeast
Bahamas Wed night, and then shift southeastward into the
Caribbean Islands Thu and Thu night. Large N swell will accompany
this front, with seas of 12 ft or greater north of 22N and east
of 73W. Yet another cold front is expected to move off
northeastern Florida late Sat, with fresh to strong southerly
winds ahead of it Fri evening through Sat. This new front is
expected to reach from 31N70W to southern Florida late Sun before
stalling.

$$

Forecaster Chan
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