[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201714
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Sat Aug 20 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...

Potential Tropical Cyclone Four is centered near 23.6N 96.4W at
20/1500 UTC or 140 nm SSE of mouth of the Rio Grande moving NW at
12 kt. Estimated minimum central pressure is 1010 mb. Maximum
sustained wind speed is 30 kt with gusts to 40 kt. Seas are 5-7 ft
from 22N to 26N between 94W and 98W, increasing to 7-10 ft from
23N to 25N between 95W and 97W. Scattered moderate convection is
noted from 21N to 26N between 93W and 98W. On the forecast track,
the current forward motion is expected to continue, bringing the
system across northeastern Mexico and southern Texas this evening
through early Sunday. The disturbance is expected to produce total rainfall
amounts of 1 to 3 inches, with isolated totals of 5 inches, along
the eastern coast of Mexico from the northern portions of the state
of Veracruz across the state of Tamaulipas to Nuevo Leon through
today.  Rainfall of 1 to 3 inches will be possible in South Texas
through Sunday morning, with continuing uncertainty in how far north
and west these amounts will be realized.  The potential exists for
flash flooding elsewhere along the track of the disturbance.
Swells generated by this system are forecast to affect eastern
Mexico and southern Texas today and Sunday. These swells are likely
to cause life-threatening surf and rip current conditions. The
disturbance may become a tropical storm later today before
reaching the coast of northeastern Mexico. Please consult products
from your local weather forecast office.

Please, read the latest HIGH SEAS FORECAST issued by the National
Hurricane Center at website
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest
Potential Tropical Cyclone Four NHC Forecast/Advisory and Public
Advisory at www.hurricanes.gov for more details.

...TROPICAL WAVES...

A tropical wave that moved off the coast of Africa early this
morning is now analyzed along 19.5W, from 11N to 23N, with an
estimated westward motion of 15-20 kt. Scattered moderate
convection, likely enhanced by the Monsoon Trough, is from 11N to
18N between 18W and 24W. This tropical wave has a low chance of
tropical cyclone development over the next five days.

An eastern Atlantic tropical wave is along 33W, from 21N southward,
moving west at 10-15 kt. Scattered moderate convection is from
08N to 10N between 31W and 38W.

A central Caribbean tropical wave is along 69W, from 23N
southward, moving west at 15-20 kt. The 1200 UTC Upper Air
Sounding from Santo Domingo indicated the wave is approaching but
has not passed through the city. Scattered showers and tstorms are
noted near and over Hispaniola and inland over Venezuela.

...MONSOON TROUGH/ITCZ...

A monsoon trough enters the Atlantic at the coast of Mauritania
near 18N16W to 13N23W to 09N50W. Aside from the convection
described in the Tropical Waves section above, scattered moderate
convection is from 08N to 14N between 26W and 31W.

GULF OF MEXICO...

Please see the SPECIAL FEATURES section for more details on
Potential Tropical Cyclone Four.

Outside of the influence of Potential Tropical Cyclone Four,
gentle to moderate anticyclonic winds prevail along the western
periphery of the Bermuda-Azores High. Seas are 1-3 ft in the E
Gulf, and 3-5 ft in the W Gulf north of 25N and south of 22N.

For the forecast, Potential Tropical Cyclone Four is near 23.6N
96.4W 1010 mb at 10 AM CDT, moving NW at 11 kt. Maximum sustained
winds are 30 kt with gusts to 40 kt. Four may become a brief
tropical storm by this evening near 25N 97.5W before making
landfall in northeastern Mexico. Four will move inland near
27N99W by early Sun. Seas are forecast to peak near 11 ft with the
strongest winds. Heavy squalls associated with this system will
continue over the far western Gulf through late tonight or early
Sun. Winds and seas will subside early Sun. Weak ridging will
prevail over the Gulf early next week, leading to gentle to
moderate winds.

CARIBBEAN SEA...

The Bermuda-Azores High continues to extend ridging into the
Caribbean, providing gentle to moderate trades across the basin.
Trades are locally fresh in the south-central Caribbean, based on
the lastest scatterometer pass. Seas are 4-6 ft in the E, Central,
and SW Caribbean, and 2-4 ft in the NW Caribbean. Seas are 6-8 ft
from 10N to 12N between 75W and 77W, co-located with the
aformentioned fresh trades.

For the forecast, surface ridging north of the area along with
the passage of a tropical wave currently along 70W will continue
to support moderate to fresh trade winds in the eastern and
central Caribbean through tonight. Fresh to locally strong NE
winds are expected across the Windward Passage tonight and Sun
night. The ridge will weaken Sun night through Tue, diminishing
the winds across the region to gentle to moderate speeds.

ATLANTIC OCEAN...

The Atlantic remains dominated by the Bermuda-Azores High centered
north of the discussion waters. Weak surface troughs are along
54W and 44W, north of 25N. Anticyclonic flow is gentle to moderate
across the basin, per this morning's scatterometer data. E to NE
winds are fresh on approach to and within the Windward Passage.
Seas are 4-6 ft across the Atlantic, as confirmed by satellite
altimeter data this morning. However, seas are 6-8 ft south of the
Cabo Verde Islands in the E Atlantic, from 07N to 14N east of 27W,
in an area of fresh to strong SW winds.

For the forecast W of 55W, the subtropical ridge will change
little through Sun night, supporting moderate to fresh easterly
winds S of 25N through the weekend. Fresh to locally strong winds
are likely N of Hispaniola and the approaches of the Windward
Passage tonight and Sun night. A weak surface trough will move
westward from 65W to 75W Mon and Mon night. The trough will weaken
the ridge, thus diminishing winds to gentle to moderate speeds.

$$
Mahoney
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