[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201748
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Fri Aug 20 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
1630 UTC.

...SPECIAL FEATURES...

Hurricane Grace is centered near 20.6N 94.3W at 20/1500 UTC or
175 nm E of Veracruz Mexico and moving W at 12 kt. Estimated
minimum central pressure is 982 mb. Maximum sustained wind speed
is 75 kt with gusts to 90 kt. Peak seas are currently 26 ft.
Numerous moderate to strong convection is noted across the SW
Gulf, including the W and central Bay of Campeche. Grace will
track across the SW Gulf to 20.4N 95.9W this evening, then move
inland and weaken to a tropical storm near 20.0N 98.2W Sat
morning, be near Michoacan, Mexico, Sat evening, and dissipate Sun
morning. Please read the latest NHC Public Advisory at
https://www.nhc.noaa.gov/text/MIATCPAT2.shtml and Forecast/
Advisory at https://www.nhc.noaa.gov/text/MIATCMAT2.shtml for more
details.

Tropical Storm Henri is centered near 30.4N 73.7W at 20/1500 UTC
or 300 nm SSE of Cape Hatteras, North Carolina and moving NW at 6
kt. Estimated minimum central pressure is 996 mb. Maximum
sustained wind speed is 55 kt with gusts to 65 kt. Peak seas are
currently 13 ft. Numerous moderate to isolated strong convection
is noted from 28N to 31N between 71W and 75W. Henri will move to
31.5N 73.7W this evening, strengthen to a hurricane near 34.1N
72.7W Sat morning, then reach 37.3N 71.8W Sat evening. By Sun
morning, Hurricane Henri will be well north of the area near 39.8N
71.7W. Please read the latest NHC Public Advisory at
https://www.nhc.noaa.gov/text/MIATCPAT3.shtml and Forecast/Advisory
at https://www.nhc.noaa.gov/text/MIATCMAT3.shtml for more details.

...TROPICAL WAVES...

A newly analyzed Atlantic tropical wave is just off the African
coast near 17W from 20N southward and moving W at 5 to 10 kt.
Scattered moderate convection is seen from 10N to 18N between the
African coast and 24W.

Another Atlantic tropical wave is along 33W from 20N southward and
moving W at 15 to 20 kt. Scattered moderate convection is noted
from 10N to 15N between 29W and 35W.

A third Atlantic tropical wave is near 44W from 21N southward of
and moving W at 15 to 20 kt. Scattered moderate convection is
present from 05N to 12N between 42W and 50W.

A Caribbean tropical wave is along 65W from 21N southward across
Puerto Rico and the Virgin Islands to Venezuela, and moving W at
15 to 20 kt. Scattered showers and isolated thunderstorms are
over the Windward Islands and E central Caribbean.

Another Caribbean tropical wave is near 75W from E Cuba southward
to N Colombia, and moving W near 10 kt. Much drier air at mid
levels is hindering significant convection from flaring up near
this wave.

...MONSOON TROUGH/ITCZ...

A monsoon trough extends from the coast of Senegal near 15N17W to
12N36W to 10N50W. The ITCZ then continues from 10N50W to 12N57W
just E of the Windward Islands. Scattered moderate convection is
present near the monsoon trough 05N to 14N between 35W and 42W.
Scattered showers are evident near the ITCZ from 09N to 12N
between 50W and 56W.

The E Pacific monsoon trough extends into the SW Caribbean Sea
from near the Costa Rica-Panama border to northern Colombia.
Scattered showers and thunderstorms are flaring up across the SW
Caribbean and near the coast of Panama and Costa Rica.

...GULF OF MEXICO...

Refer to the Special Features section above for details on
Hurricane Grace.

Other than Hurricane Grace, a surface ridge reaches southeastward
from the N central Gulf through S Florida; providing light to
gentle S to SE and seas at 2 to 5 ft. Moderate to fresh E to SE
winds and seas of 6 to 12 ft are found near the NW and central
Gulf.

For the forecast, Grace is near 20.6N 94.3W 982 mb at 11 AM EDT
or 1500 UTC and moving W at 12 kt. Maximum sustained winds are 75
kt with gusts to 90 kt. Grace will move to 20.4N 95.9W this
evening, then inland and weaken to a tropical storm near 20.0N
98.2W Sat morning, be near Michoacan, Mexico, Sat evening, and
dissipate Sun morning. High pressure will build in the wake of
Grace and prevail through early next week.

...CARIBBEAN SEA...

Convergent trade winds are coupling with divergent winds aloft to
trigger scattered showers and thunderstorms over the Dominican
Republic and central Caribbean Basin, and also near the coast of
Honduras and Nicaragua. For additional convection, refer to the
Tropical Waves and Monsoon Trough/ITCZ sections above.

Moderate to fresh E to SE winds and seas at 5 to 7 ft are noted
along the E coast of the Yucatan Peninsula, and the N central
basin. Gentle to moderate trades and seas of 4 to 6 ft prevail for
the rest of the basin.

For the forecast, moderate to fresh trade winds will dominate,
except for nightly pulsing locally fresh to strong winds in the
Gulf of Honduras through Sat night, and also in the central
Caribbean starting Mon.

...ATLANTIC OCEAN...

Refer to the Special Features section above for details on
Tropical Storm Henri. Convergent winds feeding toward Tropical
Storm Henri are producing scattered showers and isolated
thunderstorms N of the Bahamas, N of 27N between 75W and 78W.
Please read the Tropical Waves and Monsoon Trough/ITCZ sections
for additional convection across the Atlantic Basin.

The Atlantic ridge stretches from the 1021 mb Azores high,
passing S of Bermuda to S Florida. Light to Gentle winds and seas
at 3 to 5 ft are found N of 27N between the NW African coast and
67W. Moderate to fresh with locally strong winds and seas of 5 to
8 ft are present N of 28N, E of Tropical Storm Henri between 67W
and 71W, and also W of Henri between 75W and 77W. Gentle to
moderate NE trades and seas of 4 to 7 ft are found from 16N to 27N
between the African coast and Lesser Antilles. Light to gentle SE
to S winds and seas at 3 to 4 ft are evident across the Bahamas
and near the E Florida coast. Gentle to moderate winds and seas at
4 to 6 ft prevail for the rest of the basin.

For the forecast west of 55W, Tropical Storm Henri is near 30.4N
73.7W 996 mb at 11 AM EDT or 1500 UTC and moving NW at 6 kt.
Maximum sustained winds 55 kt gusts 65 kt. Henri will move to
31.5N 73.7W this evening, strengthen to a hurricane near 34.1N
72.7W Sat morning, then reach 37.3N 71.8W Sat evening. By Sun
morning, Hurricane Henri will be well north of the area near 39.8N
71.7W. Otherwise, moderate to fresh E to SE winds will prevail E
and across the Bahamas Fri through Mon, except for fresh to
possibly locally strong winds at night north of Hispaniola and the
approaches to the Windward Passage.

$$

Chan
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