[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201812
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Tue Jun 20 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
1500 UTC.

...SPECIAL FEATURES...

Tropical Storm Bret: Tropical Storm Bret is centered near 11.9N
47W at 20/1500 UTC or 945 nm E of the Southern Windward Islands
and moving W at 18 kt. Estimated minimum central pressure is 1008
mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt.
Seas 12 to 14 ft extend up to 80 nm in the N semicircle with peak
seas of 15 ft near the center. Seas of 8 to 11 ft extend northward
up to 280 nm from the center. Moderate scattered convection can be
seen up to 230 nm SW and E of the center. On the forecast track,
Bret should be approaching the Lesser Antilles, possible the
Windward Islands around Thu as at moderate tropical storm strength.
Bret is forecast to slowly weaken after crossing the Lesser
Antilles into the Caribbean Sea Friday and Saturday. Regardless of
its strength, it will bring a risk of flooding from heavy
rainfall, strong winds, and dangerous storm surge and waves to the
Windward Islands. Given the larger than usual uncertainty in the
track forecast, it is too early to specify the location and
magnitude of where these hazards could occur. However, everyone in
the Lesser Antilles, Puerto Rico, and the Virgin Islands should
closely monitor updates to the forecast for Bret and have their
hurricane plan in place. Please read the latest HIGH SEAS FORECAST
issued by National Hurricane Center at website
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest T.S.
Bret Forecast/Advisory and Public Advisory at www.hurricanes.gov
for more details.

Invest Area (AL93): A tropical wave in the Eastern Atlantic
near 32W from 03N to 14N is moving west around 15 kt. A 1011 mb
low pressure is analyzed along the wave axis near 9N32W. Winds
are currently fresh to locally strong north of the low-pressure
center, generating 5 to 7 ft seas. Widely scattered moderate
convection is observed from 07N to 10N between 33W and 38W.
Environmental conditions appear favorable for further development
of this system, and a tropical depression will likely form within
a couple of days while the system moves westward at 10 to 15 kt
across the central tropical Atlantic. There is high probability
of formation through the next 2 to 7 days. Please refer to the
latest Tropical Weather Outlook at www.hurricanes.gov, for more
details.

...TROPICAL WAVES...

A western Atlantic tropical wave is just east of Windward Islands
near 57W from 16N southward across the Guyana-Suriname border, and
moving west at 15 to 20 kt. Widely scattered showers and isolated
thunderstorms are found from 09N to 16N between 52W and 58W.

A Caribbean tropical wave is near 79W from 14N southward across
Panama into the East Pacific and moving west at 15 to 20 kt.
Isolated thunderstorms are seen near the coast of Costa Rica and
Panama. As this wave is entering the East Pacific, this will be
the last time being mentioned.

...MONSOON TROUGH/ITCZ...

A monsoon trough extends southwestward from near the Mauritania-
Senegal border, passing south of the Cabo Verde Islands near
13N22W and Invest Area 93L mentioned in the Special Features
section above to 09N36W.  Numerous moderate to scattered strong
convection is flaring up from 04N to 08N between the Sierra
Leone- Liberia coast and 16W. Widely scattered moderate convection
is seen farther west from 07N to 09N between 20W and 26W. No ITCZ
is present based on the latest analysis.

...GULF OF MEXICO...

A cold front curves westward from the Florida Panhandle to just
north of New Orleans. Scattered showers and thunderstorms are
occurring near and up to 100 nm south of the front. Otherwise, a
broad surface ridge extending westward from southern Florida to
near Tampico, Mexico continues to dominate the region. Fresh with
locally strong westerly winds and seas of 5 to 7 ft are present
across the northeastern Gulf near the cold front. Moderate to
fresh southerly winds with 3 to 5 ft seas are found at the western
Gulf. Gentle to moderate ESE to S winds and seas at 2 to 4 ft
prevail for the rest of the Gulf.

For the forecast, the surface ridge will persist through the
upcoming weekend. Fresh winds will pulse north of the Yucatan
peninsula each night through Sat as a diurnal trough develops and
moves offshore. Elsewhere, gentle to moderate winds will prevail,
locally fresh at times. Smoke from agricultural fires in Mexico
will produce hazy skies over the central and western Gulf for at
least the next day or two.

...CARIBBEAN SEA...

Please refer to the Special Features section for information on
Tropical Storm Bret, which is forecast to approach the Lesser
Antilles around Thu.

Convergent trade winds are triggering scattered shower and
isolated thunderstorms at the Gulf of Honduras. Otherwise, the
gradient between subtropical high pressure and the Colombian Low
is supporting strong easterly trade winds in the south-central
Caribbean with 7 to 10 ft seas. Fresh ESE winds with 6 to 8 ft
seas are noted at the north-central basin. Light to gentle winds
and seas of 1 to 3 ft are evident south of Cuba and near the
Windward Passage. Gentle to moderate ENE to SE winds with 3 to 6
ft seas are noted for the remainder fo the basin.

For the forecast, Tropical Storm Bret will begin to gradually
strengthen as it moves to near 12.3N 49.2W this evening, to near
12.7N 51.9W Wed morning with maximum sustained winds 45 kt gusts
50 kt, to near 13.2N 54.5W Wed evening, to near 13.6N 57.3W early
Thu with maximum sustained winds 55 kt gusts 65 kt. Bret is
forecast to maintain intensity as it approaches the Lesser
Antilles Thu evening and move into the eastern Caribbean Sea near
14.2N 63.6W early on Fri. Bret is forecast to begin to weaken as
it nears 14.4N 70.4W early Sat with maximum sustained winds 45 kt
gusts 55 kt and dissipate by early on Mon. Otherwise, the pressure
gradient between the Bermuda High and the Colombian Low will
support fresh to strong E trades across the central Caribbean
through early Thu. Moderate to fresh E winds are expected in the
Gulf of Honduras.

...ATLANTIC OCEAN...

Please refer to the Special Features section for information on
Tropical Storm Bret and Invest Area AL93 located in the eastern
Atlantic Ocean.

An outflow boundary is causing scattered showers and
thunderstorms from the northeastern Florida coast to near 30N78W.
Convergent southerly winds are coupling with modest divergent flow
aloft to trigger scattered moderate convection at the central and
southeast Bahamas to southwest of Bermuda, and north of Puerto
Rico from 21N to 24N between 63W and 68W.

A large dome of Mid-Atlantic High is supporting light to gentle
with locally moderate winds north of 22N between 20W and the
Florida-Georgia coast. To the south excluding T.S. Bret, moderate
to fresh NE to E trades and seas of 5 to 7 ft exist from 08N to
22N between 30W and the Lesser Antilles. Near the Cabo Verde
Islands, gentle to moderate NE trades and NW monsoonal winds are
present from 12N to 22N between the Africa coast and 30W. Near the
Canary Islands, light to gentle northerly winds with 1 to 3 ft
seas are noted north of 22N between the northwest Africa coast and
20W. Light to gentle southerly and monsoonal winds with 4 to 6 ft
seas in southerly swell prevail elsewhere in the Atlantic Basin.

For the forecast W of 55W, the Mid-Atlantic High will continue to
control the weather regime through Sat. Moderate to fresh S to
SW winds N of 27N and W of 70W will change little through the end
of the week. Otherwise, mainly gentle to moderate anticyclonic
winds will prevail the next several days, locally fresh offshore
northern Hispaniola and offshore northern Florida.

$$

Forecaster Chan
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