[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 150607
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 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 0000 UTC surface analysis and satellite imagery through
0630 UTC.

...SPECIAL FEATURES...

The remnants of Fred are in the SE Gulf of Mexico, off the NW
coast of Cuba, near 23.8N 84.3W at 0300 UTC, or about 110 nm W-NW
of Havana, Cuba. It is moving WNW at 8 kt with an estimated
minimum central pressure at 1012 mb. Maximum sustained wind speed
is 30 kt with gusts to 40 kt occurring in squalls N and NE of the
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 is
expected to gradually turn toward the northwest today, then north
tonight and Monday with some strengthening. This will bring Fred
or its remnants into the E central Gulf tonight and Monday, and
move inland over the northern Gulf coast Monday night. Fred is
expected to redevelop into a tropical depression later today and
then a tropical storm near 26.8N 86.9W late tonight or early
Monday. 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 Lesser Antilles near 16.8N 62.4W
at 0300 UTC or about 145 nm E-SE of St. Croix. It is moving WNW
at 17 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 9-12 ft range. Despite being a
small tropical storm, interaction with a mid-level trough near
16N64W is producing numerous showers and scattered thunderstorms
to the W and SW of the center, over the Leeward Islands and E
Caribbean Sea. Grace is forecast to move toward the west-northwest
with a gradual decrease in forward speed during the next several
days. This will bring Grace very close to the Virgin Islands later
today and Puerto Rico tonight, then over the Dominican Republic
and Haiti on Monday and Monday night, and then between the
southeastern Bahamas and Cuba on Tuesday. Some strengthening is
forecast through tonight. Grace is likely to weaken while it moves
over Hispaniola Monday and Monday night. 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 is along 23W from 19N southward and
moving W at 10 to 15 kt. Scattered moderate convection is noted
from 06N to 09N and between 19W and 26W.

Another Atlantic tropical wave is near 40W from 20N southward and
moving W at 20 to 25 kt. Scattered moderate convection is seen
from 06N to 08N between 37W and 43W.

A Caribbean tropical wave is along 72W from 25N southward across
Haiti into NW Venezuela, and moving W at 15 to 20 kt. Recent
scatterometer satellite data continue to depict a broad surface
trough, especially on the northern portion of the wave. Aided by
an upper-level trough SW of Bermuda near 28N67W, scattered showers
and isolated thunderstorms are present from 22N to 25N between 66W
and 73W, and also S of Hispaniola from 15N to 17N between 70W and
74W.

Another tropical wave is near 88W from 19N southward across the
Yucatan Peninsula and Guatemala into the E Pacific, and moving W
near 15 kt. Numerous moderate to strong convection is flaring up
along the S coast of Guatemala and El Salvador.

...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 05N53W 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 19W. Scattered moderate convection is found near the low
from 10N to 14N between 20W and 25W, and also near the monsoon
trough from 01N to 07N between 27W and 36W. Scattered moderate to
isolated strong convection is seen N of the ITCZ from 06N to 09N
between 48W and 56W, N of French Guiana and Suriname.

...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 23.8N 84.3W 1012 mb
at 11 PM EDT or 0300 UTC moving WNW at 8 kt. Maximum sustained
winds 30 kt gusts 40 kt. Fred will move to near 25.3N 85.7W Sun
morning with maximum sustained winds 35 kt gusts 45 kt, to near
26.8N 86.9W Sun evening, to near 28.3N 87.8W Mon morning with
maximum sustained winds 45 kt gusts to 55 kt, to near 29.7N 88.0W
Mon evening, and weaken to a depression inland near 31.4N 87.9W
Tue morning. Fred will dissipate late on Wed. Tropical Storm Grace
currently entering the far 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 N of 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 16.8N 62.4W 1010 mb
at 11 PM EDT or UTC 0300 moving WNW at 17 kt. Maximum sustained
winds 35 kt gusts 45 kt. Grace will move to near 17.3N 64.6W Sun
morning, inland over Puerto Rico near 18.1N 67.0W Sun evening,
inland over the eastern Dominican Republic near 18.7N 69.1W Mon
morning, inland over the Dominican Republic near 19.3N 70.9W Mon
evening, then over water near 20.2N 73.2W Tue morning with maximum
sustained winds 35 kt gusts 45 kt and to near 21.2N 75.8W Tue
evening. Grace will change little in intensity as it moves across
the Straits of Florida to near 23.7N 81.0W by late Wed and into
the southeastern Gulf of Mexico thereafter.

...ATLANTIC OCEAN...

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

An upper-level low SE of Bermuda near 30N56W is causing scattered
showers and a few thunderstorms N of 27N between 51W and 57W.
Divergent flow E and SE of 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 N 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 SE to SW 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 16.8N
62.4W 1010 mb at 11 PM EDT or 0300 UTC moving WNW at 17 kt.
Maximum sustained winds 35 kt gusts 45 kt. Grace will move to near
17.3N 64.6W Sun morning, inland over Puerto Rico near 18.1N 67.0W
Sun evening, inland over the eastern Dominican Republic near
18.7N 69.1W Mon morning, inland over the Dominican Republic near
19.3N 70.9W Mon evening, then over water near 20.2N 73.2W Tue
morning with maximum sustained winds 35 kt gusts 45 kt and to near
21.2N 75.8W Tue evening. Grace will change little in intensity as
it moves across the Straits of Florida to near 23.7N 81.0W by
late Wed and into the southeastern Gulf of Mexico thereafter.
Otherwise, high pressure will persist across the area through the
period.

$$

Chan
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