[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 041816
TWDAT

000
AXNT20 KNHC 041745
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Sun Oct 4 2020

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 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1200 UTC surface analysis and satellite imagery through
1715 UTC.

...SPECIAL FEATURES...

Tropical Storm Gamma is centered off the north coast of Yucatan
near 22.2N 88.2W at 04/1500 UTC or 100 nm ENE of Progreso Mexico
moving N at 2 kt. Estimated minimum central pressure is 996 mb.
Maximum sustained wind speed is 50 kt with gusts to 60 kt.
Numerous strong convection is within 90 nm of the center.
Scattered moderate to strong convection is elsewhere over the
SE Gulf of Mexico, S Florida, W Cuba, the Yucatan Channel, and
the N Yucatan Peninsula, from 21N-28N between 81W-91W.
Seas are building as Gamma moves farther offshore. A long fetch
of persistent NE winds to the north of Gamma is support seas to
16 ft in the south- central Gulf. Gamma should turn toward the
west or west-southwest tonight or Monday, and a slow
southwestward motion should continue Monday night through early
Wednesday. On the forecast track, the center of Gamma will
meander offshore of the northern Yucatan Peninsula and over the
extreme southern Gulf of Mexico today, and pass near or just
offshore of the northern coast of the Yucatan Peninsula on
Monday and Tuesday. Little change in strength is expected
through this evening. Gradual weakening is anticipated to begin
later tonight or on Monday and continue into Tuesday.
Please read the latest NHC Public Advisory at
https://www.nhc.noaa.gov/text/MIATCPAT5.shtml and Forecast/
Advisory at https://www.nhc.noaa.gov/text/MIATCMAT5.shtml
for more details.

A tropical wave with an axis along 76W S of 20N is moving
W at 10 kt producing scattered moderate to strong convection
from 11N-17N between 71W-80W. Environmental conditions are
expected to be conducive for additional development, and a
tropical depression is likely to form within the next day or
two.  The system should move west-northwestward at 10 to 15 kt
across the central and western Caribbean Sea today through
Tuesday, and then move into the southern or southeastern Gulf
of Mexico on Tuesday night and Wednesday. Locally heavy rainfall
and gusty winds will be possible across portions of Hispaniola,
Jamaica, Cuba, and the Cayman Islands during the next few days,
and interests on those islands should monitor the progress of
this disturbance. This system has a high chance of development
within the next 48 hours.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 45W from 20N southward,
moving W at 05-10 kt. A 1010 mb low is along the wave near
13N45W. Isolated moderate convection within 240 nm of the wave
axis. This system has not become any better organized, and any
development during the next day or so should be slow to occur
while it moves west-northwestward or northwestward. Significant
development is not expected beyond that time due to the system
moving into a region of strong upper-level winds. This system
has a low chance of development over the next 48 hours.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through coastal sections of Senegal
near 14N17W to 08N22W to 05N38W. The ITCZ continues from 05N38W
to 09N44W and from 09N47W to the coast of French Guiana near
05N52W. Scattered moderate convection is from 02N-11N between
10W-25W. Isolated moderate convection is from 02N-08N between
25W-40W.

GULF OF MEXICO...

Please see the Special Features section above for information on
T.S. Gamma.

As of 04/1500 UTC, the tail-end of a stationary front is over
central Florida from Daytona Beach Florida to S of Orlando
Florida. Scattered moderate convection is within 60 nm of the
front. Moderate to strong N to NW winds span across the eastern
and central Gulf, including the eastern half of the Bay of
Campeche. Gentle easterly winds are off the coasts of Texas
through Alabama. Seas are from 3-5 ft across the northern and
western Gulf with 9-16 ft across the south-central Gulf near
T.S. Gamma.

Low pressure along a central Caribbean tropical wave is expected
to move from the northern Caribbean across western Cuba into the
southeast Gulf Tue, possibly as a tropical depression or
tropical storm. A cold front will move into the northern Gulf
Mon, then stall and dissipate over the central Gulf through mid
week as the low pressure moves northward.

CARIBBEAN SEA...

Please see the Special Features section on information regarding
T.S. Gamma, and the tropical wave in the central Caribbean.

The monsoon trough extends across the southwest Caribbean from
12N78W to the coast of Costa Rica near 10N83W. Scattered
showers are within 90 nm of the axis. Scattered moderate
convection is over the Virgin Islands and N of Puerto Rico from
18N-20N between 63W-67W. Gentle to moderate trade winds prevail
across most of the Caribbean with fresh winds near the Greater
Antilles and light winds in the SW Caribbean. Seas are from
3-6 ft across most of the basin with upwards of 8 ft near the
low along the tropical wave, and 5 to 7 ft near the Yucatan
Channel

The focus turns to the development and track of the tropical
wave south of Haiti. There is a high chance that a tropical
depression or tropical storm may form by late Mon or early Tue
as the low moves west-northwest through the northwest Caribbean,
and to the south of Cuba.

ATLANTIC OCEAN...

The tail-end of a stationary front over the W Atlantic extends
from 31N80W to Daytona Beach Florida. Scattered showers are
within 60 nm of the front. The tail-end of a dissipating
stationary front is further E from 31N78W to 29N79W. Scattered
showers are within 45 nm of the front. A surface trough is over
the central Atlantic from 31N49W to 24N51W. Isolated moderate
convection is within 120 nm of the trough. A broad surface ridge
extends from 1031 mb high near 39N37W west of the Azores to
just east of the fronts. The gradient on the southwest side of
this ridge is supporting fresh to strong E winds off the north
coast of Hispaniola. There may be one more round of fresh to
strong winds off Hispaniola tonight. Winds and seas will
diminish thereafter as the ridge shifts east ahead of a third
weak front that will move over the Atlantic waters east of NE
Florida by early Mon, drift south through Tue then stall from
31N73W to near W Palm Beach Florida by mid week.

In the eastern Atlantic, fresh to strong NE winds and seas
to 9 ft are active off the African coast of Western Sahara and
Mauritania. Elsewhere, generally moderate trade winds persist
across the Atlantic with mostly 5 to 7 ft seas.

$$
Formosa
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