[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 131138
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Fri Aug 13 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
1030 UTC.

...SPECIAL FEATURES...

Tropical Depression Fred is centered near the coast of eastern
Cuba at 22.0N 76.7W at 13/0900 UTC or about 520 nm east-southeast
of Key West, Florida. It is moving WNW at 9 kt with estimated
minimum central pressure at 1013 mb. Maximum sustained wind speed
is 30 kt with gusts to 40 kt. Wave heights with Fred are in the
8-10 ft range. Satellite imagery shows that the center of Fred
is exposed once again as it is out running its deep convection
of the scattered to moderate type intensity that is occurring
from 18N to 21N between 74W-77W including portions of eastern
Cuba. Similar convection is within 30 nm of a line from 16N77W to
18N76W. Scattered moderate convection is north of eastern Cuba to
25N between 72W-77W including the southeastern and central Bahama
Islands. Fred is forecast to turn toward the northwest or Sat. On
this forecast track, Fred is expected to move along or just north
of eastern and central Cuba through tonight, be near the Florida
Keys on Sat, and near the west coast of Florida on Sun. From today
into Mon, 3 to 7 inches of rain are anticipated across the Keys,
southern and central Florida north towards the Big Bend, with
isolated maximum totals of 10 inches. 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 Fred
NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov
for more details.

A small area of low pressure with a pressure of 1010 mb is near
15N47W or about 870 nm east of the Lesser Antilles. It is
producing clusters of scattered moderate convection within
240 nm to its west. An overnight ASCAT data pass suggested
that the low pressure is elongated in an east to west fashion,
with the strong winds of 20-25 kt present over its eastern
section. Despite this, environmental conditions are expected
to gradually become more conducive for additional development and
a tropical depression is likely to form within the next couple of
days. This system is forecast to move generally westward at about
20 mph across the tropical Atlantic, reaching portions of the
Leeward Islands Sat night, and Virgin Islands on Sun. Interests
in these locations should monitor the progress of this disturbance.
This system has a high chance of tropical cyclone formation
during the next 48 hours. Please read the latest NHC Tropical
Weather Outlook at hurricanes.gov for more details.

...TROPICAL WAVES...

A far eastern Atlantic tropical wave has its axis along 20W from
03N to 21N, moving westward around 10 kt. The wave marks the
leading edge of deep atmospheric moisture. Scattered moderate
to isolated strong convection is seen east of the wave to the
coast of Africa and from 06N to 10N.

A central Atlantic tropical wave is west of the Special Features
low pressure along 49W from 03N to 20N. It is moving westward
near 15 kt. Scattered moderate convection is within 120 nm either
side of the axis from 03N to 09N.

Another tropical wave is along 59W/60W south of 23N to South
America. It is moving westward also near 15 kt. Scattered
moderate convection is within 120 nm west of the wave from
19N to 22N. This wave will move across the Lesser Antilles and
into the eastern Caribbean Sea today.

A Caribbean tropical wave has its axis along 80W south of 16N to
across central Panama into the E Pacific Ocean. It is moving
westward at 10 to 15 kt. Scattered showers and thunderstorms are
noted within 120 nm east of the wave from 14N to 16N.

...MONSOON TROUGH/ITCZ...

THe monsoon trough extends across the coast of Africa near the
Senegal-Gambia border at 14N16W to 08N21W and to 06N31W. The
ITCZ then continues from 06N31W to near 07N40W. Aside from
convection mentioned above with the tropical wave along 20W,
scattered moderate convection is seen within 180 nm north
of the ITCZ between 32W-36W.

...GULF OF MEXICO...

An upper-level trough is over the eastern Gulf. It is helping to
trigger scattered showers and isolated thunderstorms over the
central and southern across the eastern Gulf and over South
Florida. Locally fresh winds and seas up to 4 ft are expected near
heavier showers and stronger thunderstorms. Otherwise a ridge of
high pressure over the N Gulf near 29N87W is promoting gentle to
moderate ENE to ESE winds and seas of 2 to 3 ft across most of the
Gulf.

For the forecast, Tropical Depression Fred along the north coast
of Cuba near 22.0N 76.7W 1013 mb at 5 AM EDT moving WNW at 9 kt.
Maximum sustained winds 30 kt gusts 40 kt. Fred will strengthen to
a tropical storm near 22.6N 78.4W this afternoon with maximum
sustained winds 35 kt gusts 45 kt, reach near 23.6N 80.2W late
tonight, near 24.8N 81.5W Sat afternoon with maximum sustained
winds 40 kt gusts 50 kt, to near 26.4N 82.5W late Sat night, to
near 28.1N 83.7W early Sun afternoon with maximum sustained winds
45 kt guts 55 kt, to near 29.6N 84.6W late Sun night and weaken to
a tropical depression as it moves inland to near 32.5N 85.8W by
late Mon night. Expect hazardous marine conditions over most of
the eastern Gulf Sat through Mon. Otherwise, gentle to moderate
winds and slight seas will persist through the period.

...CARIBBEAN SEA...

Refer to the Special Features section for information on Tropical
Depression Fred, and the Tropical Waves section for convection in
the basin.

Gentle to moderate trades and seas at 3 to 5 ft are seen across
the central and E basin. Gentle trades and seas of 1 to 3 ft
prevails for the rest of the basin.

For the forecast, Tropical Depression Fred near the north coast of
Cuba will strengthen to a tropical storm today and move into the
Gulf of Mexico Sat. Fresh to locally strong winds will persist
across most the eastern and central Caribbean through Fri,
becoming light to gentle during the weekend. Light to gentle winds
and slight seas will persist elsewhere. Low pressure located well
east of the Lesser Antilles is expected to reach portions of the
Leeward Islands Sat night, and the Virgin Islands Sun as a
possible tropical cyclone. Expect strong gusty winds along with
scattered to numerous showers and thunderstorms with this system.

...ATLANTIC OCEAN...

Refer to the Special Features section for details on Tropical
Depression Fred and an area of low pressure in the central
Atlantic near 14N45W.

Two upper-level lows, one is S of Bermuda near 28N63W and another
one is over northern Florida near 29N83W. They are triggering
scattered showers and isolated thunderstorms from 25N to 29N
between 58W and 65W, and over S Florida and the NW Bahamas. For
additional convection across the Atlantic Basin, refer to the
Monsoon Trough/ITCZ section above.

A ridge of high pressure stretching west-southwestward from the N
central Atlantic across Bermuda to N Florida. Light to gentle
winds and seas at 2 to 4 ft dominate N of 25N between 24W and 69W.
Moderate to fresh trades and seas of 4 to 6 ft are evident from
10N and 25N between the African coast and the Lesser Antilles, and
also N of 19N between 69W and the Florida-Georgia coast. Mainly
gentle to moderate winds and seas of 4 to 6 ft seas prevail for
the rest of the basin.

For the forecast west of 65W, Tropical Depression Fred near 22.0N
76.7W 1013 mb at 5 AM EDT is moving WNW at 9 kt. Maximum
sustained winds 30 kt gusts 40 kt. Fred will strengthen to a
tropical storm near 22.6N 78.4W this afternoon with maximum
sustained winds 35 kt gust 45 kt, reach near 23.6N 80.2W late
tonight and across the rest of the Straits of Florida and to the
eastern Gulf of Mexico Sat. Numerous squalls and thunderstorms
associated over the far southwest part will gradually shift
westward through Sat. The northern part of a tropical wave will
move across the far southern waters today through late Sun. Low
pressure located well east of the Lesser Antilles is pressure is
expected to reach portions of the Leeward Islands Sat night and
the Virgin Islands Sun as a possible tropical cyclone. Expect
strong gusty winds along with scattered to numerous showers and
thunderstorms with this system.

$$
Aguirre
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