[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 181756
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Wed May 18 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
1630 UTC.

...SPECIAL FEATURES...

Global models continue to suggest a Central American Gyre (CAG)
forming near the western Caribbean by Fri, and then gradually
shifting westward across Central America through early next week.
CAG tends to enhance SW monsoon flow, and lift the monsoon trough
well north of its typical position. This will increase convergent
surface winds and advect abundant moisture northward, triggering
widespread strong convection over Central America. Expect heavy
rainfall from the southern parts of Guatemala and Honduras,
southward to Panama. Extreme rainfall is possible near the Pacific
coast of these countries, and also over southern Honduras and NE
Nicaragua. This will increase the potential for flooding,
especially near valleys in mountainous terrain. Please refer to
products issued by your local weather service for more
information.

...TROPICAL WAVES...

A Atlantic tropical wave is near 10N33W and southward, moving
west at 15 to 20 kt. Scattered moderate convection is seen near
the southern portion of the wave from 02N to 05N between 33W and
37W.

A Caribbean tropical wave is southwest of Jamaica near 17N78W and
southward, moving west-northwest near 10 kt. Enhanced by a mid-
level trough in the vicinity, scattered moderate to isolated
strong convection is evident over the SW Caribbean Sea from 10N to
14N between 77W and 82W.

...MONSOON TROUGH/ITCZ...

A monsoon trough exits the African coast near the Mauritania-
Senegal border to south of the Cabo Verde Islands at 13N23W.
Scattered moderate to isolated strong convection is found south of
the trough near and off the Guinea-Sierra Leone-Liberia coast
from 05N to 10N between 11W and 19W. An ITCZ extends from 01N37W
to north of the Amazon River Delta area near 02N50W. Numerous
moderate to isolated strong convection is noted from 01N to 05N
between 82W and the Brazilian coast.

The eastern end of the Pacific monsoon trough and an embedded
1010 mb low near 10N81W are producing scattered moderate
convection near the Costa Rica-Panama-Colombia coast and adjacent
Caribbean waters.

...GULF OF MEXICO...

A surface ridge reaches west-southwestward from a 1018 mb high
over the NW Gulf to near Tampico, Mexico. Light to gentle winds
with 1 to 3 ft seas are found near the high across the E Gulf.
Gentle to moderate SE winds and seas at 2 to 3 ft are present over
the SW Gulf, while moderate to fresh S winds and seas of 3 to 5 ft
dominate the NW Gulf.

For the forecast, the high will maintain moderate to fresh S to
SE winds over the W Gulf through Sat, and light to gentle
variable winds across the E Gulf through Thu afternoon. Then a
broad area of low pressure is expected to develop along Central
America near Fri, tightening gradient between itself and the
Bermuda High. This should allow moderate to fresh SE to S winds to
spread eastward across the entire Gulf thru early next week.
Also, fresh to strong E to SE winds are forecast to develop off
the northern Yucatan peninsula Fri into Sun night.

...CARIBBEAN SEA...

Please see the Special Features section for information on a
potential heavy rainfall event.

Convergent trades in the wake of a surface trough over western
Cuba and west of the Cayman Islands are causing scattered showers
across central and eastern Cuba and the Cayman Islands. Refer to
the Tropical Wave and Monsoon Trough/ITCZ sections for additional
weather in the basin. Moderate to fresh easterly trades with 6 to
7 ft seas are found over the south-central basin, just north of
Colombia. Gentle to moderate easterly trades and seas at 4 to 5 ft
are evident across the eastern, north-central and SW basin.
Gentle to moderate trades and seas of 2 to 4 ft prevail for the NW
basin.

For the forecast, surface ridging over the western Atlantic will
continue to support moderate to fresh trade winds across the
eastern and central Caribbean through today, with fresh to strong
winds pulsing off Venezuela and northwest Colombia. Winds and
seas across the basin are expected to increase Thu night into the
weekend as the ridge strengthens and broad low pressure forms
along Central America. Strongest winds expected to be over the
northwest and south-central Caribbean during this period.

...ATLANTIC OCEAN...

A surface trough runs southward from 28N73W across the central
Bahamas to near the Windward Passage. Convergent southerly winds
east of the trough are combining with mid-level wind shear to
trigger scattered moderate convection from 22N to 30N between 59W
and the central/SE Bahamas. A dissipating stationary front runs
southwestward from southwest of Madeira across 31N19W to 27N28W
with a surface trough to its west near 28N32W. Scattered moderate
convection is seen near these features north of 26N between 20W
and 35W. Southwesterly upper-level winds are streaming widespread
thick cirrus across the east-central Atlantic, including the Cabo
Verde Islands.

The Atlantic ridge stretches west-southwestward from a 1022 mb
high near Madeira across 31N24W to the NW Bahamas. This feature is
promoting light to gentle winds and 3 to 5 ft seas north of 20N
between 35W and the Florida coast/Bahamas. Farther east, gentle to
moderate with locally fresh NE to E trades and 5 to 8 ft seas in
northerly swell is evident north of 25N between the African coast
and 35W. Gentle to moderate NE to ESE trades and seas at 5 to 8 ft
are noted from the Equator to 20N between 27W and the Lesser
Antilles. Gentle to moderate SSW to WNW monsoonal winds and seas
of 4 to 5 ft prevail for the remainder of the Atlantic Basin.

For the forecast west of 55W, the Atlantic ridge across the area
will slightly weaken today into Thu as the tail of a cold front
moves eastward to the north of 30N. The ridge will restore on Thu
and support mainly light to gentle variable winds across the
region through Sun night, except for moderate to fresh winds north
of Hispaniola and the Great Bahama Bank.

$$

Chan
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