[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121054
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Thu Aug 12 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 0600 UTC surface analysis and satellite imagery through
1040 UTC.

...SPECIAL FEATURES...

Tropical Depression Fred is centered over the northern entrance to
the Windward Passage near 20.2N 73.5W at 12/0900 UTC or 60 nm SSW
of Great Inagua Island, moving WNW at 14 kt. Estimated minimum
central pressure is 1010 mb. Maximum sustained wind speed is 30 kt
with gusts to 40 kt. Seas are reaching as high as 8 ft off the
north coast of Haiti. Numerous moderate to isolated strong
thunderstorms are active well to the east of Fred, across the
eastern Dominican Republic. A few showers are noted off southwest
Haiti as well. Please read the latest NHC Public Advisory at
https://www.nhc.noaa.gov/text/MIATCPAT1.shtml and Forecast/
Advisory at https://www.nhc.noaa.gov/text/MIATCMAT1.shtml for more
details.

...TROPICAL WAVES...

A tropical wave extends south of 20N along 38W, moving W at 15
kt. Scattered moderate to isolated strong convection is noted
west of the wave axis from 09N to 15N between 40W and 45W.
Environmental conditions are expected to become gradually
conducive for development of this system, and a tropical
depression could form by early next week while moving generally
westward across the tropical Atlantic. This system could reach
portions of the Leeward Islands by late Saturday.

A tropical wave extends south of 20N along 54W, moving W at 15
kt. Scattered showers are from 08N to 10N between 53W and 55W.

A tropical wave is in the central Caribbean just to the south of
Haiti with axis near 74W, moving W at 10-15 kt. No significant
showers or thunderstorms are noted with this tropical wave.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Guinea-Bissau near
12N16W to 10N25W to 11N45W. The ITCZ continues from 11N45W to
11N55W to 09N60W. Aside from the convection mentioned in the
Tropical Waves section, no significant convection is noted.

...GULF OF MEXICO...

An upper level trough supports a few showers and isolated tstms
over the northwest Gulf while a low aloft supports similar
convection over the west central Gulf and the coast of Veracruz.
A surface ridge persists from the Atlantic through the northern
Gulf, supporting gentle to moderate E to SE flow, except NE flow
off the Yucatan peninsula. Seas ranged from 2 to 3 ft across the
basin.

For the forecast, T.S. Fred is expected to move across the
eastern Straits of Florida as a tropical storm by Fri night, enter
the far southeast Gulf of Mexico on Sat, and move northward along
the far eastern Gulf into early next week. Meanwhile, moderate to
fresh E winds will pulse off the northwest Yucatan Peninsula into
the Bay of Campeche overnight and Thu night in association with a
trough that forms late in the day. Elsewhere, gentle to moderate
winds and slight seas will persist through the period.

...CARIBBEAN SEA...

Aside showers and thunderstorms near Hispaniola associated with
Fred, scattered showers and thunderstorms are noted over the
southwest basin off Costa Rica being supported by the NE Pacific
monsoon trough, and north of Grand Cayman Island. Fresh NE winds
across the Windward Passage earlier tonight have likely
diminished, except for the possibility of stronger winds near the
entrance to the Windward Passage. Moderate to fresh trades cover
the eastern and central portion of the basin while gentle to
moderate winds are elsewhere. Seas ranged from 3 to 4 ft in the
eastern and central Caribbean, 4 to 5 ft in the southwest
Caribbean and 1 to 3 ft in the northwestern Caribbean.

For the forecast, Fred is expected to remain north of the
Caribbean, and will not have in major impact on the basin.
Moderate to occasionally fresh winds will persist across most
the eastern and central Caribbean as Fred continues to move away
from the area and high pressure builds to the north. Light to
gentle breezes and slight seas will persist elsewhere. Looking
ahead, a fairly strong tropical wave will move into the Windward
Islands by Sat night, and into the north central Caribbean by
Mon.

...ATLANTIC OCEAN...

Near gale force winds and seas to 8 ft north of Haiti, on the
periphery of T.D. Fred. Fresh to strong E winds and seas to 8 ft
are likely around 15N along the tropical wave at 38W. Elsewhere
across the subtropical and tropical north Atlantic, generally
moderate E winds persist with moderate seas to the south of the
Bermuda-Azores ridge. A few thunderstorms are active across the
central Bahamas and in the waters east of the Bahamas to 65W. An
upper low near 28N63W is supporting a few thunderstorms within 150
nm mainly to its east.

For the forecast, mostly moderate E to SE winds and moderate seas
will persist between Fred and the Bermuda-Azores high farther to
the northeast in the north central Atlantic.

$$
Christensen
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