[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 031044
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Sat Oct 3 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 near 19.4N 86.9W at 03/0900 UTC
or 70 nm S of Cozumel Mexico moving NW at 8 kt. Estimated
minimum central pressure is 992 mb. Maximum sustained wind speed
is 45 kt with gusts to 55 kt. Strong thunderstorms
are evident across the inner core of Gamma and in a prominent band
to north of the center impacting northern Quintana Roo. Another
strong band is moving northwest toward western Cuba. Given the
size and relatively slow movement of Gamma across the northeastern
portion of the Yucatan peninsula through tonight, the main threat
continues to be heavy rainfall that could result in life-
threatening flash flooding over portions of the Yucatan Peninsula,
far western Cuba and well away from the center in the Mexican
states of Campeche, Tabasco, and northern Chiapas. Please monitor
local weather advisories for more details. For marine interests,
strong winds and seas at least as high as 13 ft will impact the
Yucatan Channel through tonight. In the south- central Gulf, a
long fetch of persistent near-gale force NE winds is already
causing seas to 12 ft off the north coast of Yucatan, along with
rough surf conditions. Adverse marine conditions will persist into
mid week in the south-central Gulf due to the expected track of
Gamma. 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.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 42W from 18N southward,
moving W at 10-15 kt. A broad area of disorganized area of
scattered moderate to isolated strong convection is noted from
08N-16N between 33W-44W.

A Caribbean Sea tropical wave is along 70W from 18N southward,
moving W at 10 kt. Numerous moderate to scattered strong
convection is evident over the entrance to the Gulf of Venezuela,
to the west of the wave axis.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through coastal sections of Senegal
near 14N17W to 07N30W. The ITCZ continues from 07N30W to 07N40W,
and from 06N43W to the coast of Brazil near 03N51W. Convection
near the ITCZ is associated with the tropical wave along 42W,
described above.

GULF OF MEXICO...

At 0300 UTC, a stationary front extends from southwest Florida
near 26N81W to 22N90W. Another stationary front farther north
extends off the Tampa Bay, Florida coast near 26N84W. In the far
southwest Gulf, a surface trough is analyzed off the coast of
Veracruz. An earlier scatterometer satellite pass indicated
strong to near- gale force NW winds funneling between the trough
and the coast, south of 21N. Large area of strong to near-gale
force NE winds are noted over the south-central Gulf, between
Gamma to the southeast and high pressure north of the area. A
recent altimeter satellite pass indicated seas were reaching 12 ft
off the Yucatan coast. Moderate NE winds and 3 to 5 ft seas
persist elsewhere over the northern Gulf. Seas over the southern
Bay of Campeche are likely up to 9 ft, in a combination of mixed
NW and NE swell.

For the forecast, Gamma will enter the south-central Gulf and
reach near 21.7N 88.0W Sun afternoon, then move to 21.8N 88.4W
Mon morning, 21.6N 89.3W Mon afternoon, and 21.2N 90.5W Tue
morning. Gamma is expected to change little in intensity as it
moves across the eastern Bay of Campeche through early Wed.
Meanwhile a weak stationary front reaching from SW Florida to the
south-central Gulf will dissipate late by today ahead of Gamma.
Another stationary front from central Florida to the central Gulf
will dissipate late Sun into Mon. A cold front will move into the
northern Gulf Mon and stall over the central Gulf through mid
week.

CARIBBEAN SEA...

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

A few showers and thunderstorms are noted off the southern coast
of the Dominican Republic this morning, likely due to overnight
drainage flow converging off the coast, but also near where the
northern portion of the tropical wave is passing. Strong E winds
are noted off the southern coast of Haiti as well, with seas
likely reaching 8 ft. Moderate to fresh trade winds and 5 to 7 ft
seas are noted elsewhere east of 75W, and north of 18N
particularly between Jamaica and eastern Cuba. Light to gentle
breezes and modest seas are noted over the southwest Caribbean.

For the forecast, Gamma will move to 20.2N 87.4W this afternoon,
inland to 21.1N 87.9W Sun morning, then into the south-central
Gulf of Mexico through Sun afternoon. Winds and seas will
gradually diminish over the far northwest Caribbean through Mon.
Elsewhere, fresh to strong trades are expected over the eastern
and central Caribbean through Sun night. Winds and seas will
subside through mid week across the basin as Gamma moves farther
west and high pressure north of the area weakens slightly.

ATLANTIC OCEAN...

A stationary front extends from 31N73W to 26N80W. A surface trough
is analyzed south of the front, reaching from the northern Bahamas
to central Cuba. A few showers are active over the northern
Bahamas where the trough and front intersect. Another stationary
front is analyzed farther north, from 31N78W to 28N80W. No
significant weather is associated with that front. A broad
surface ridge extends from 1033 mb high pressure near 40N37W 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. Fresh winds and a few showers are also noted
north of a surface trough embedded in the ridge along 48W from 23N
to 28N. Fresh winds are also associated with the tropical wave
near 42W. In the eastern Atlantic, Fresh to strong NE winds and
seas to 9 ft are active off the African coast of Mauritania in
Elsewhere, generally moderate trade winds persist across the
Atlantic with mostly 5 to 7 ft seas.

For the forecast for waters west of 65W, the stationary front
extending from 31N73W to 26N80W will gradually dissipate late
today or tonight. The other stationary front extending from
31N78W to 28N80W will dissipate through late Sun. Meanwhile, the
high pressure north of our area will support moderate to fresh
trades south of 22N, occasionally pulsing to strong north of
Hispaniola during the overnight hours through Sun night. Looking
ahead, a third weak front will move over the Atlantic waters east
of NE Florida late Sun or early Mon, drift south through Tue then
stall from 31N73W to near W Palm Beach Florida by mid week.

$$

Christensen
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