[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231811
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Fri Jul 23 2021

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
1730 UTC.

...SPECIAL FEATURES...

As of 1800 UTC, a 1017 mb low pressure center near 30N79W, about
140 nm southeast of the Georgia coast. Disorganized numerous
moderate to isolated strong convection is noted displaced to the
east and south of the center due to strong upper level wind shear.
Seas of 2-4 ft are occurring north of 28N and between 73W and
78W. Environmental conditions appear marginally conducive for
additional development and a tropical depression could form over
the next couple of days as the system meanders over the Gulf
Stream, just offshore of the southeastern United States.

Heavy Rainfall in Southern Central America: High moisture levels,
persistent strong trade wind flow, and favorable conditions aloft
will together support heavy rainfall for much of southern Central
America through early next week. The heaviest rain is expected
over the Caribbean coast of Costa Rica and southeast Nicaragua.
These rains could cause significant flooding and mudslides in some
areas. Currently, scattered moderate convection is noted along
the Caribbean coast from northern Costa Rica through western
Panama.

...TROPICAL WAVES...

An Atlantic tropical wave is analyzed along 54W, south of 18N,
moving W near 15 kt. A surface reflection is noted on the
scatterometer satellite pass from 1300 UTC. Scattered moderate
convection is noted within 100 nm east of the wave axis from 06N
to 09N.

A Caribbean tropical wave is analyzed along 68W, south of 22N,
moving W at 15 to 20 kt. No significant convection is associated
with this wave.

Another Caribbean tropical wave is analyzed along 81W, south of
25N, moving W near 15 kt. No significant convection is associated
with this wave.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic Ocean near Guinea-Bissau
near 12N16W and extends to 11N42W. The ITCZ continues from 11N43W
to 11N53W. Scattered moderate and isolated strong convection is
noted within 300 nm south of these features between 42W and 55W.

GULF OF MEXICO...

The Bermuda High extends across Florida to a regional 1022 mb
high pressure near 25N90W, which dominates the Gulf of Mexico.
This system is keeping fair weather conditions in place, except
for an area of showers and thunderstorms off the SW Florida
peninsula. Recent scatterometer satellite data showed gentle winds
prevailing across the basin. Seas 3-5 ft over the western Gulf,
and 1-3 ft elsewhere.

For the forecast, the Bermuda High will drift westward over the
weekend as low pressure meanders offshore of the Atlantic waters
of Florida, providing tranquil marine conditions across the Gulf
through early next week.

CARIBBEAN SEA...

A recent scatterometer satellite pass showed strong to near gale
force winds within 60 nm of the Colombia. Fresh to strong trades
prevail elsewhere across the central and eastern Caribbean. Gentle
to moderate winds are found elsewhere. Seas are 8-11 ft in the
south-central Caribbean, 5-7 ft in the reminder of the central
and eastern Caribbean, and 3-5 ft elsewhere.

For the forecast, high pressure centered across the central
Atlantic extends W-SW to central Florida and is combining with low
pressure over N Colombia to support fresh to strong E winds over
the central Caribbean. Fresh to strong winds are expected to
continue across the central Caribbean through early Sat before the
ridge weakens west of 75W.

ATLANTIC OCEAN...

An expansive 1028 mb high pressure near 34N43W is supporting
mainly dry weather conditions across the basin. An area of fresh
to strong winds is found south of 25N and west of 45W due to the
pressure gradient between the strong ridge and lower pressures
over South America. Seas within this region are 6-8 ft. Another
area of fresh to strong NE winds surrounds the Canary Islands east
of 25W, with winds reaching near gale force between the islands.
Seas are 5-7 ft east of 25W. Elsewhere, gentle to moderate flow
prevails and seas of 4-6 ft.

For the forecast, moderate to fresh trades will prevail south of
25N through Sun. Low pressure along a frontal boundary will sink
southward today through the weekend off the Georgia and NE Florida
coasts. Environmental conditions are forecast to be marginally
conducive for some gradual development over the weekend and into
early next week while the system drifts offshore of the
southeastern United States. Regardless of development, showers and
thunderstorms and moderate to fresh winds can be expected over
the weekend off the Florida coast as the ridge remains in place.

$$
DELGADO/MORA
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