[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 222312
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 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 1800 UTC surface analysis and satellite imagery through
2300 UTC.

...SPECIAL FEATURES...

Caribbean Gale Warning: The pressure gradient between the
Atlantic ridge and the Colombian/Panamanian low will support
gale force winds off the coast of the Colombia overnight with 8
to 13 ft seas. The strongest winds will be within 90 to 120 nm of
the Colombian coast, mainly between Barranquilla and Santa Marta.
Strong to near gale force winds will also impact most of the
south-central Caribbean as well. For more information, please see
the High Seas Forecast issued by the National Hurricane Center at
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml

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 SE Nicaragua through western Panama.

...TROPICAL WAVES...

An Atlantic tropical wave extends its axis along 46W, south of
19N, moving W near 20 kt. Scattered moderate convection is evident
from 08N to 12N between 42W and 48W.

Another tropical wave is over the eastern Caribbean along 62W,
south of 20N, moving W at near 15 kt. No significant convection is
evident near this tropical wave.

A third tropical wave from roughly the Turks/Caicos to northeast
Colombia, moving W at 15 to 20 kt. This wave is not producing any
notable shower activity at this time.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic Ocean near Guinea-Bissau
near 12N16W and extends SW to 10N22W to 10N41W. The ITCZ continues
from 10N41W to 10N45W. Scattered moderate to isolated strong
convection is noted within 120 nm south of these features between
35W and 50W.

GULF OF MEXICO...

1023 mb high pressure near 26N87W is the major feature over the Gulf
of Mexico. This is supporting moderate E to SE winds across the
west-central Gulf and Bay of Campeche with 2 to 4 ft, and light
to gentle breezes elsewhere with seas 2 ft or less. No significant
shower or thunderstorm activity is evident across the basin.

For the forecast, the current pattern will persist and continue
to provide tranquil conditions across the basin into early next
week. Fresh to locally strong E to SE winds will pulse tonight NW
of the Yucatan Peninsula related to a trough that forms off the
west coast of the Peninsula each day.

CARIBBEAN SEA...

A Gale Warning is in effect for the south-central Caribbean.
Please see the Special Features section for more details.

A tropical wave is moving across the basin. Refer to the section
above for details.

Fresh to strong trades prevail across the central Caribbean,
including the Windward Passage, and the Gulf of Honduras, with
fresh trades in the eastern Caribbean. Gentle to moderate winds
are found elsewhere. Seas are 7-9 ft in the central Caribbean and
5-7 ft elsewhere, except for 2-4 ft south of Cuba.

For the forecast, the Bermuda High north of the area combined
with low pressure over northern Colombia continues to support
fresh to strong E winds over the central Caribbean. Gale force
winds will pulse once more tonight north of Colombia and end Sat
morning. Fresh to strong winds are expected to continue across the
central Caribbean through Fri. Fresh to strong winds are expected
in the Gulf of Honduras through tonight.

ATLANTIC OCEAN...

A few showers and thunderstorms are noted north of 28N between 70W
and 75W, related to divergent flow aloft between an upper trough
in that region and an upper low centered near 25N65W. A surface
ridge extends from 1029 mb high pressure near 34N42W to east-
central Florida. South of this ridge axis, a ship reported 20 kt
winds near the northern approaches to the Windward Passage,
hinting that fresh to strong E winds are active along the north
coast of Hispaniola. This is in an area where a tropical wave is
moving through, and seas may be reaching up to 6 ft. Elsewhere
moderate to fresh E winds persist south of the ridge over the
tropical Atlantic and 6 to 8 ft seas, highest east of leeward
Islands. Gentle winds and slight seas persist along and north of the
ridge axis, with 3 to 5 ft seas. Farther east, strong to near gale force
winds are east of 20W, surrounding the Canary Islands. Moderate
to fresh NE winds are noted elsewhere east of 35W, with 5 to 7 ft
seas.

For the forecast west of 65W, fresh to strong E winds will pulse
in the afternoon and evening north of Hispaniola through Fri.
Moderate to fresh trades will prevail elsewhere south of 20N. A
low along a frontal boundary will sink southward during the
weekend off the NE Florida coast. Environmental conditions are
forecast to be marginally conducive for some gradual development
over the weekend and into early next week while the system drifts
slowly 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.

$$
Christensen
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