[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 261712
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Wed Jul 26 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
1700 UTC.

...TROPICAL WAVES...

An eastern Atlantic tropical wave is west of the Cabo Verde
Islands near 27W from 19N southward, and moving west at 15 to 20
kt. Scattered moderate convection is present from 13N to 17N and
between 24W and 29W.

A central Atlantic tropical wave is near 45W from 18N southward,
and moving west around 15 kt. Scattered moderate convection is
observed from 05N to 10N and between 41W and 46W.

A pronounced eastern Caribbean tropical wave is near 70W from the
Dominican Republic southward into northwestern Venezuela, and
moving west around 15 kt. Scattered showers and isolated
thunderstorms are occurring from just north of the ABC Islands
northward to the southern coast of Hispaniola and Puerto Rico.

...MONSOON TROUGH/ITCZ...

A monsoon trough reaches the Atlantic through the Mauritania
coast near Nouakchott, then curves southwestward through 11N30W
to north of French Guiana at 08N52W. Aside from convection
related to the tropical waves mentioned above, scattered moderate
convection is present from 04N to 19N between the central Africa
coast and 22W, and up to 200 nm along either side of the trough
between 30W and 40W. There is no ITCZ based on the latest
analysis.

The eastern end of the East Pacific monsoon trough is triggering
scattered showers and thunderstorms in the Caribbean waters near
Costa Rica, Panama and northwestern Colombia.

...GULF OF MEXICO...

Modest convergent easterly winds are coupling with moist divergent
southerly flow aloft to trigger scattered showers and isolated
thunderstorms across the east-central and southeastern Gulf,
including southern Florida and the Florida Keys. An upper-level
low near 26N93W is generating isolated thunderstorms over the
northwestern Gulf. A surface trough is producing scattered showers
and thunderstorms at the western Bay of Campeche.

A surface ridge extends southwestward from a 1021 mb high over the
Mississippi-Alabama border to south of Tampico, Mexico. This
feature is supporting light to gentle winds and seas of 1 to 3 ft
across the northern Gulf. Gentle to moderate ENE to E winds and 2
to 4 ft seas exist for the southern Gulf, including the Florida
Straits and Bay of Campeche.

For the forecast, the modest surface ridge will remain the
dominant feature across the basin into late this week. This will
support mainly gentle to moderate winds, except at the eastern
Bay of Campeche where winds will be enhanced by a thermal trough
moving off the Yucatan Peninsula nightly.

...CARIBBEAN SEA...

A broad upper-level low near the western tip of Cuba is inducing
scattered showers and isolated thunderstorms near the Cayman
Islands and off the coast of Belize. Refer to the Tropical Waves
and Monsoon Trough/ITCZ sections for additional weather in the
Caribbean Basin.

The sub-tropical ridge near 26N70W maintains a trade-wind pattern
over much of the basin. Enhanced by a robust tropical wave,
moderate to fresh with locally strong ENE to ESE winds and seas
of 5 to 8 ft are found over the central and eastern basin, and
near the Windward Passage. Gentle to moderate with locally fresh
ENE winds and 4 to 6 ft seas are seen at the southwestern basin,
except gentle monsoonal winds with 3 to 5 ft seas in easterly
swell north of Costa Rica and Panama. Gentle to moderate ENE winds
and seas at 2 to 4 ft prevail for the rest of the basin.

For the forecast, the robust tropical wave will continue to
produce fresh to locally strong winds, showers and thunderstorms
over the central and part of western basin through Thu. Some
locally heavy rains are probable over portions of the adjacent
land areas. Afterward, pressure gradient between the sub-tropical
ridge and Colombian Low should maintain fresh to strong winds and
rough seas at the central basin.

...ATLANTIC OCEAN...

A surface trough located between Bermuda and the Bahamas near
28N73W is joining forces with divergent flow aloft to trigger
scattered moderate convection from the northwest and central
Bahamas northeastward to southwest of Bermuda. The northern tip of
a tropical wave at the Caribbean is causing isolated thunderstorms
north of Hispaniola and Puerto Rico. Refer to the Monsoon
Trough/ITCZ and Tropical Waves sections at the beginning for
additional convection in the Atlantic Basin.

Gentle to moderate E to SE winds and seas of 2 to 4 ft are present
north of 20N between 75W and the Georgia-Florida coast. Otherwise,
a large dome of 1028 mb high near 34N47W is supporting gentle to
moderate with locally fresh NE to ESE winds with 5 to 7 ft seas
north of 21N between 20W and 75W. Near the Canary Islands,
moderate to fresh NNE trades and seas at 5 to 8 ft are evident
north of 20N between the Africa coast and 20W. For the tropical
Atlantic, gentle to moderate with locally fresh NE to ENE trades
and 6 to 8 ft seas dominate from 09N to 20N/21N between the Cabo
Verde Islands and the Lesser Antilles. Gentle to moderate
southerly and monsoonal westerly winds with seas of 4 to 6 ft in
moderately southerly swell prevail elsewhere in the Atlantic
Basin.

For the forecast west of 55W, high pressure centered over the
central Atlantic will gradually shift northward through the week
as a surface trough near 28N73W, moves west-northwestward toward
the southeastern U.S. coast over the next several days. Fresh
trades will pulse nightly north of Hispaniola and over the
Windward Passage. Elsewhere west of 55W, winds will be moderate
or weaker over most of the area except moderate to fresh northeast
of the Leeward Islands.

$$

Forecaster Chan
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