[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 030005
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Fri Sep 03 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 1800 UTC surface analysis and satellite imagery through
2345 UTC.

...SPECIAL FEATURES...

Hurricane Larry is centered near 13.7N 35.8W at 02/2100 UTC or
or about 665 nm west of the southernmost Cabo Verde Islands,
moving west or 280 at 16 kt. The estimated minimum pressure is
985 mb. The maximum sustained wind speed speed is 70 kt with
gusts to 85 knots. Satellite imagery shows tightly coiled bands
around the center of Larry. These bands consist of numerous
moderate to strong convection within 90 nm of the center, except
within 60 nm in the NW quadrant. Similar convection is embedded
within a wide band from 10N to 13N between 37W-40W. Scattered
moderate to isolated strong convection is separated from the
central dense overcast region of Larry within 30 nm of a line
from 13N39W to 15N40W to 17N40W. Larry is forecast to make a
gradual turn towards the west-northwest with a decrease in
forward speed is expected over the next few days. A turn to the
northwest is then expected by early next week. Significant to
possibly rapid intensification is forecast during the next couple
of days, and Larry is expected to become a major hurricane
tomorrow 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
Larry NHC Forecast/Advisory and Public Advisory at
www.hurricnes.gov for more details.

...TROPICAL WAVES...

A far eastern Atlantic tropical wave has its axis along 21W from
02N to 19N, with low pressure of 1009 mb centered on the wave
near 13N21W. This system is moving westward at 10-15 kt. Satellite
imagery shows scattered moderate to isolated strong convection
within 90 nm west of the low. Scattered moderate convection is
within 60 nm of 14N24W. This activity continues to show signs
of organization. Some limited development of this system could
occur tonight and on Fri as the low moves generally westward at
10-15 kt. After that time, conditions are expected to become
less conducive for development. Interests in the Cabo Verde
Islands should monitor the progress of this system.

A tropical wave has its axis along 57W south of 20N to inland
South America, moving westward at 10-15 kt. Scattered moderate
to isolated strong convection is within 120 nm east of the
wave from 08N to 12N and within 60 nm west of the wave from
10N to 13N.

A central Caribbean tropical wave has its axis along 76W south of
15N, moving westward near 15 kt. This tropical wave is rather
ill-defined and model guidance is presently not detecting any
signals with this wave. Only small isolated showers are seen
within 60-90 nm either side of the wave axis.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis passes through the coastal plains of
Senegal near 16N17W to low pressure of 1009 mb near 13N21W and
to 13N26W. It is interrupted by Hurricane Larry. It then
resumes to the SW of Larry at 11N40W to 08N49W and to 06N56W.
Scattered moderate convection is within 60 nm north of the
trough between 51W-55W. Otherwise, observed convection is related
to Hurricane Larry, and the tropical waves.

GULF OF MEXICO...

A stationary front is just inland the northern Gulf coast from
southwestern Georgia to Alabama, Mississippi, and into the
northern half of Louisiana. Weak high pressure is present over
the area. Scattered showers and isolated thunderstorms are over
some areas of the northern Gulf. Similar activity is along and
within 60 nm offshore the coast of Mexico from 21N to 24N.

For the forecast, the stationary front will begin to gradually
move south as a cold front and stall over far northeast Gulf
through Fri. This pattern will maintain light to gentle breezes
over most of the Gulf, with slight seas, except for fresh winds
expected to pulse northwest of the Yucatan Peninsula at night
through Sat. Looking ahead, an area of low pressure that is
currently located near the coast of Nicaragua could move over
the southwestern Gulf of Mexico during the weekend and early
next week, but by then strong upper-level winds would likely
limit significant development.

CARIBBEAN SEA...

A small 1010 mb low pressure system is centered over eastern
Honduras near 14N85W. This low is along the eastern segment of
the eastern Pacific monsoon trough that extends from 15N92W to
the low and southeastward to coast of Colombia near 10N75W.
Disorganized scattered moderate convection is seen northeast of
this low from 15N to 19N between 81W-85W, including northeastern
Honduras. A portion of the low's circulation could move over the
Gulf of Honduras on Friday. However, development there, if any,
is expected to be slow to occur. This system could then move over
the southwestern Gulf of Mexico during the weekend, but by then
unfavorable upper-level winds are likely to limit significant
development early next week while the system moves northwestward
or northward over the western Gulf of Mexico. Regardless of
development, heavy rains are possible across portions of Central
America and the Yucatan Peninsula through the weekend.

Scattered showers and isolated thunderstorms are present from
19N to 20N between 80W-85W.

Recent altimeter data passes indicate that seas are in the
3-4 ft range, except for slightly higher seas of 4-6 ft in the
Gulf of Honduras.

As for the forecast, a ridge north of the Caribbean Sea combined
with lower pressure over northern Colombia will support moderate
to fresh trade winds over the south-central Caribbean through
Sun. Fresh to locally strong E to SE winds are expected in the
Gulf of Honduras at night through the weekend. A small area of
low pressure over eastern Nicaragua is producing disorganized
shower and thunderstorm activity off eastern Honduras. The low
could move over the Gulf of Honduras on Friday where development,
if any, is expected to be slow to occur. Looking ahead,
Hurricane Larry will move NE of the Leeward Islands by late Sun
into Mon and hurricane conditions are possible in the adjacent
Atlantic waters by that time. At a minimum, large swells
generated by Hurricane Larry are expected to propagate across the
waters east of the Leeward on Sun, likely spreading beyond 65W
Mon and Mon night.

ATLANTIC OCEAN...

Please see the Special Features section for details on Hurricane
Larry.

An elongated north to south upper-level cyclonic circulation
center is near 29N69W. Scattered showers and isolated
thunderstorms are north of 26N and west of 68W. A surface trough
extends from 31N25W to 25N34W. Isolated showers and thunderstorms
are within 60 nm east of the trough north of 29N.

A 1023 mb high pressure center is located near 34N39W and a 1021
mb high is analyzed nea 32N52W.

As for the forecast, fresh southwest winds off northeast Florida
will shift northeast of the area by this evening. These winds
are ahead of a cold front forecast to weaken as it moves across
the northern waters W of 70W Sat through Sun night. Looking
ahead, Hurricane Larry will move NE of the Leeward Islands by
late Sun into Mon and hurricane conditions are possible in the
adjacent Atlantic waters by that time. At a minimum, large swells
generated by Hurricane Larry are expected to propagate across
the waters east of the Leeward on Sun, likely spreading beyond
65W Mon and Mon night.

$$
Aguirre
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