[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 041047
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 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 0600 UTC surface analysis and satellite imagery through
1000 UTC.

...SPECIAL FEATURES...

Tropical Storm Gamma is centered off the north coast of Yucatan near
22.0N 88.2W at 04/0900 UTC or 100 nm ENE of Progreso Mexico
moving N at 4 kt. Estimated minimum central pressure is 995 mb.
Maximum sustained wind speed is 45 kt with gusts to 55 kt. Large
clusters of showers and thunderstorms are active within 150 nm in
the northwest semicircle of Gamma. Additional showers and
thunderstorms are observed over the southeast Gulf from 23N to 26N
between 83W and 88W. Isolated thunderstorms are also evident over
western Cuba. Most of the thunderstorm activity has moved north
of the Yucatan Peninsula. 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
is expected to turn toward the north- northwest with decreasing
forward speed is expected on Sunday, followed by a turn to the
west or west- southwest Sunday night or Monday. On the forecast
track, the center of Gamma will pass near or north of the northern
coast of the Yucatan Peninsula Monday and Tuesday. Little change
in strength is forecast during the next few days. 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 75W southward from 18N moving
W at 10 kt is producing scattered moderate convection from 13N-
15N between 71W-77W. Environmental conditions are expected to
become more conducive for development, and a tropical depression
is likely to form during the next couple of days while the system
moves westward or west- northwestward at about 10 to 15 kt across
the central and northwestern Caribbean Sea and then into the
southern Gulf of Mexico. 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 medium chance of development through the next
48 hours and a high chance of formation through the next 5 days.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 45W from 20N southward,
moving W at 10 kt. A 1010 mb low is along the wave near 11N44W.
Scattered moderate convection is noted from 11N-17N between 41W-
48W. Some slow development of this system is possible during the
next couple of days while it moves west-northwestward or
northwestward at 10 to 15 kt. 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 and the next 5 days.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through coastal sections of Senegal
near 14N17W to 06N35W. The ITCZ continues from 06N35W to 06N43W
and from 09N47W to the coast of French Guiana near 04N52W.
Some scattered moderate convection is moving off the coast of
southern Senegal. No other significant convection is observed.

GULF OF MEXICO...

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

A stationary front continues to linger off the SW Florida coast
near 26N81W to 24N85W. Scattered moderate convection is within 80
nm of the front. Dry conditions west of 90W is inhibiting
convection from occurring over the western Gulf. 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.

Tropical Storm Gamma near 22.0N 88.2W 995 mb at 5 AM
EDT moving N at 4 kt. Maximum sustained winds 45 kt gusts 55 kt.
Gamma will move to 22.6N 88.3W this afternoon, 22.7N 88.6W Mon
morning, 22.4N 89.4W Mon afternoon, 22.0N 90.2W Tue morning,
21.5N 90.9W Tue afternoon, and 21.0N 91.6W Wed morning. Gamma
will change little in intensity as it moves westward through the
eastern Bay of Campeche. A stationary front from SW Florida near
26N81W to the SE Gulf near 24N83W will dissipate later today,
ahead of low pressure 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 11N74W
to the coast of Costa Rica near 10N82W. Scattered moderate
convection is active from 13N- 15N between 71W-77W. Isolated
thunderstorms continue to impact the Virgin Islands westward into
Puerto Rico. 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

Gamma will continue to move NW into the south-central Gulf,
allowing winds and seas over the Yucatan Channel to diminish
through Sun. The focus turns to the development and track of the
low pressure south of Haiti There is a high chance this low may
form into a tropical depression or tropical storm through next
several days as the low moves west- northwest through the
northwest Caribbean, south of Cuba.

ATLANTIC OCEAN...

A stationary front is draped off the Florida coast from 31N79W to
the coast near Melbourne, Florida at 29N80W. Another stationary
front is farther south extends from 31N74W to near West Palm
Beach, Florida at 27N80W. No significant convection is associated
with either front. Both stationary front will dissipate through
late today or tonight. A broad surface ridge extends from 1030 mb
high pressure near 38N37W 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.

Farther east, fresh winds and a few showers are also noted north
of a surface trough embedded in the ridge along 50W from 23N to
30N. Fresh winds are also associated with the tropical wave near
45W. 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.

$$
Christensen
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