[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 151107
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Sun Aug 15 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
1100 UTC.

...SPECIAL FEATURES...

The remnants of Fred are over the southeastern Gulf of Mexico
near 24.4N 84.6W at 0900 UTC, or about 100 nm west of Dry
Tortugas. It is moving NNW at 7 kt with an estimated minimum
central pressure at 1012 mb. Maximum sustained wind speed is
35 kt with gusts to 45 kt presently within 100 nm NE of the
its center. Wave heights with the remnants of Fred are in the
8-10 ft range. Latest satellite imagery shows scattered showers
and thunderstorms from W Cuba northward to the Florida Keys. Fred
will continue on its current motion through tonight, then
turn toward the north expected on Mon. On the forecast track, the
system will cross the southeastern Gulf of Mexico today, cross
the east-central and northern Gulf of Mexico tonight and Monday,
and move inland along the northern Gulf coast Mon night or early
on Tue morning. Fred is expected to redevelop into a tropical
storm later today, with gradual strengthening expected while it
moves over the Gulf of Mexico until it makes landfall.
Please read the latest HIGH SEAS FORECAST issued by the National
Hurricane Center at website-
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest NHC
Forecast/Advisory and Public Advisory at www.hurricanes.gov for
more details.

Tropical Storm Grace is over the eastern Caribbean Sea
near 16.9N 64.4W at 0900 UTC or about 50 nm SSE of St. Croix. It
is moving WNW at 14 kt, with an estimated minimum central
pressure of 1010 mb. Maximum sustained wind speed is 35 kt with
gusts to 45 kt. Wave heights with this system are in the 9-13 ft
range. Satellite imagery shows that Grace is not a well organized
tropical cyclone. Scattered moderate to strong convection is noted
from 16N to 20N between 62W-67W and from 12N to 16N between 63W-
66W. Grace is forecast to move toward the west-northwest with a
gradual decrease in forward speed during the next several days.
Some strengthening is expected before Grace reaches Hispaniola on
Monday. Weakening is forecast as the system crosses Hispaniola
Mon and Mon night. Little change in strength is expected on
Tue. Please read the latest HIGH SEAS FORECAST issued by the
National Hurricane Center at website-
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest NHC
Forecast/Advisory and Public Advisory at www.hurricanes.gov for
more details.

...TROPICAL WAVES...

An Atlantic tropical wave has its axis along 25W from
04N to 19N, moving westward t 10 to 15 kt. Scattered moderate
to isolated strong convection is within 180 nm east of the wave
from 06N to 09N and within 120 nm west of the wave from

A central Caribbean tropical wave has its axis along 73W from 25N
southward across Haiti into NW Venezuela. It is moving westward
at 15 to 20 kt Overnight ASCAT data showed  a broad surface
trough, especially on the northern portion of the wave. Aided by
an upper-level trough southwest of Bermuda near 28N67W, scattered
showers and isolated thunderstorms are present from 22N to 26N
between 67W and 73W.

A tropical wave has moved inland Central Americas near 89W south
of 19N to across the southern Yucatan Peninsula and Guatemala
and to the eastern Pacific. It is moving westward near 15 kt.
Numerous moderate to strong convection that earlier developed
along the southern coast of Guatemala and El Salvador has moved
into the eastern Pacific Ocean.

...MONSOON TROUGH/ITCZ...

A monsoon trough exits along the coast of Mauritania near 20N16W
through a low pressure centered near 12N22W to 06N40W. The ITCZ
then continues from 06N40W to 05N56W over N French Guiana.
Numerous moderate to isolated strong convection is noted near and
S of the monsoon trough from 10N to 17N between the African coast
and 20W. Scattered moderate convection is near the monsoon trough
from 01N to 07N between 27W and 36W. Scattered moderate to
isolated strong convection is within 180 north of the ITCZ between
48W and 56W.

...GULF OF MEXICO...

Refer to the Special Features section for information on the
remnants of Fred.

An upper level low over the NE Gulf near 29N85W is triggering
scattered showers and isolated thunderstorms over the NE Gulf
including the Big Band area and central W coast of Florida.
Moderate to locally fresh S to SE winds and seas of 3 to 6 ft are
expected near these thunderstorms. Gentle to moderate NE to E
winds and seas at 2 to 4 ft prevail for the rest of the Gulf.

For the forecast, the remnants of Fred near r24.4N 84.6W 1011 mb
at 5 AM EDT moving NNW at 7 kt. Maximum sustained winds 35 kt
gusts 45 kt. Fred will move to near 25.5N 85.6W this afternoon, to
near 27.0N 86.6W Mon morning, to 28.5N 87.1W Mon afternoon, to
30.3N 87.1W Tue morning, inland to 32.5N 86.8W Tue afternoon, and
inland to 35.0N 85.8W Wed morning. Fred will dissipate early Thu.
Tropical Storm Grace over the eastern Caribbean Sea is forecast to
move near the northern coast of Cuba and Straits of Florida Wed
and Wed night and into the southeastern Gulf of Mexico Thu and Thu
night.

...CARIBBEAN SEA...

Refer to the Special Features section for information on Tropical
Storm Grace and the Tropical Waves section for convection in the
Caribbean Basin.

Convergent trade winds are producing scattered showers and a few
thunderstorms north f Colombia and Panama. Moderate with locally
fresh trades and seas of 4 to 6 ft are present S central and SE
Caribbean, while gentle to moderate trades and seas of 3 to 4 ft
prevail across the rest of the basin.

For the forecast, Tropical Storm Grace near 16.9N 64.4W 1010 mb
at 5 AM EDT moving WNW at 18 kt. Maximum sustained winds 35 kt
gusts 45 kt. Grace will move to near 17.5N 66.6W this afternoon,
inland the eastern Dominican Republic near 18.3N 68.9W late
tonight with maximum sustained winds 45 gusts 55 kt, continue
inland near 18.9N 70.6W Mon afternoon with maximum sustained winds
35 gusts 45 kt, inland near 19.8N 72.6W late Mon night, to near
20.9N 75.3W Tue afternoon, and to near 22.0N 78.0W late Tue night.
Grace will change little in intensity as it moves into the
eastern Gulf of Mexico near 23.9N 82.5W late Wed night.

...ATLANTIC OCEAN...

Refer to the Special Features section for information on Tropical
Storm Grace.

An upper-level low near 30N54W is producing scattered showers and
thunderstorms north of 28N between 54W and 64W. Divergent flow
east and southeast f an upper-level low of the NE Gulf is
coupling with convergent SE winds to trigger scattered showers and
isolated thunderstorms over SE Florida and off the Florida-
Georgia coast. For additional convection across the Atlantic
Basin, please read the Tropical Waves and Monsoon Trough/ITCZ
sections above.

The persistent Atlantic ridge over the N Atlantic continues to
support light to gentle winds and seas at 2 to 4 ft N of 24N
between 31W and 73W. Moderate with locally fresh NE to SE winds
and seas of 5 to 7 ft are found N of 19N between the NW African
coast and 31W, and also north of 20N between 73W and the Florida-
Georgia coast. Gentle to moderate trades and seas of 4 to 6 ft
are evident from 10N to 20N between the African coast and the
Lesser Antilles. Mainly gentle southeast to southwest winds and
seas of 4 to 5 ft prevail across the remainder of the basin.

For the forecast west of 65W, Tropical Storm Grace near
16.9N 64.4W 1010 mb at 5 AM EDT moving WNW at 18 kt. Maximum
sustained winds 35 kt gusts 45 kt. Grace will move to near 17.5N
66.6W this afternoon, inland the eastern Dominican Republic near
18.3N 68.9W late tonight with maximum sustained winds 45 gusts 55
kt, continue inland near 18.9N 70.6W Mon afternoon with maximum
sustained winds 35 gusts 45 kt, inland near 19.8N 72.6W late Mon
night, to near 20.9N 75.3W Tue afternoon, and to near 22.0N 78.0W
late Tue night. Grace will change little in intensity as it moves
into the eastern Gulf of Mexico near 23.9N 82.5W late Wed night.
Otherwise, high pressure will persist across the area through the
period.

$$
Aguirre
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