[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 081244
TWDAT

Tropical Weather Discussion...Update
NWS National Hurricane Center Miami FL
1205 UTC Wed Sep 8 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
1230 UTC.

Updated Special Features section below

...SPECIAL FEATURES...

Major Hurricane Larry is centered near 27.0N 57.7W at 08/1200 UTC
or 485 nm SE of Bermuda and moving NW at 9 kt. Estimated minimum
central pressure is 966 mb. Maximum sustained wind speed is 100
kt with gusts to 120 kt. Numerous moderate to strong convection is
noted near the center from 26N to 29N between 55W and 59W. Larry
is expected a NW track through early Thursday morning, then
gradually turning N with the center passing E of Bermuda on Thu
afternoon. Gradual weakening is forecast for the next few days
which should bring Larry below hurricane intensity during this
weekend, with more rapid weakening possible thereafter. Please,
read the latest NHC Public Advisory at:
https://www.nhc.noaa.gov/text/MIATCPAT2.shtml, and the
Forecast/Advisory at:
https://www.nhc.noaa.gov/text/MIATCMAT2.shtml, for more details.

A surface trough in the Gulf of Mexico along 90W, in combination
with an upper level disturbance, is causing scattered showers and
isolated thunderstorms from 26N to the Florida Panhandle and
Mississippi coastlines. This trough is expected to move NE over
the NE Gulf through this afternoon. Upper-level winds could
become slightly more favorable to support some tropical or
subtropical development as the system nears the northern Gulf
coast tonight or early Thursday. The disturbance is then expected
to cross the southeastern United States, and some additional
development will be possible after it emerges off the southeastern
United States coast late this week. Regardless of development,
areas of heavy rainfall will be possible across portions of the
Florida panhandle and southern Georgia through Thursday, with
localized flooding possible. There is a medium chance of tropical
or subtropical formation in the next 48 hours. Please, read the
Tropical Weather Outlook, at the following web address:
https://www.nhc.noaa.gov/text/MIATWOAT.shtml for more details.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 22W, from the Cabo Verde
Islands southward, moving W at around 10 kt. Scattered moderate
convection is noted from 08N to 13N between 19W and 22W.

An Atlantic Ocean tropical wave is along 37W, from 16N southward,
moving W at around 10 kt. Scattered moderate convection is noted
from 05N to 13N between 32W and 43W.

An Atlantic Ocean tropical wave is along 58W, from 15N southward,
moving W at 10 to 15 kt. Scattered moderate to isolated strong
convection is noted from 07N to 09N between 48W and 58W.

A tropical wave previously over Central America has moved into the
eastern Pacific, with no further associated convection in the
western Caribbean.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal plains of Senegal
near 15N17W to 10N27W to 07N37W. The ITCZ continues from 07N37W to
03N46W. Other than convection associated with the tropical waves
mentioned in the section above, scattered moderate convection is
noted from 04N to 09N between 43W and 46W.

...GULF OF MEXICO...

Please see Special Features section above for details on a trough
of low pressure with the potential for tropical development in the
NE Gulf.

Moderate to locally fresh SW winds are occurring in the vicinity
of this trough, mainly between 85W and 92W. To the east of that,
gentle southerly winds prevail, while to the west, winds are light
and variable. Seas throughout the basin are generally 3 ft or
less.

For the forecast, the low pressure trough will move NE over the
NE Gulf today, and upper level winds may become slightly more
favorable for tropical or subtropical development as the system
nears the northern Gulf coast tonight or early Thu. Regardless of
development, heavy rain is possible across portions of the Florida
Panhandle through Thu.

...CARIBBEAN SEA...

The eastern extension of the eastern Pacific Ocean monsoon trough
crosses Panama an Costa Rica along 10W and continues into
Colombia. A fairly broad area of moderate convection is associated
with this feature, S of 15N and W of 72W. Elsewhere across the
basin, mainly moderate trades prevail with dry conditions, aside
from a cluster of moderate trade wind thunderstorms in the
vicinity of the Cayman Islands. Seas range from 4 to 6 ft.

For the forecast, swells generated by Major Hurricane Larry will
continue to propagate across the Atlantic waters of the Leeward
Islands, Puerto Rico, and Hispaniola through Wed night. Seas will
gradually subside from E to W. Elsewhere, mainly moderate trade
winds will persist, pulsing to fresh to possibly locally strong
winds off Colombia mainly at night.


...ATLANTIC OCEAN...

Please see Special Features section above for details on Major
Hurricane Larry and on the potential for low pressure to form in
the NE Gulf and bring tropical development to areas offshore N
Florida late this week.

Outside of Larry, a weakening surface trough extends from 30N67W
to 25N72W. Scattered moderate convection is noted N of 25N between
67W and 72W. High pressure dominates much of the rest of the
basin, anchored by a 1016 mb center N of the NW Bahamas and a 1021
mb center near 33N30W. For areas W of the influence of Larry,
gentle and variable winds prevail. To the E, and N of 20N, gentle
to moderate E winds prevail, with areas S of 20N having moderate
to fresh trades.

Swell from Hurricane Larry encompasses a wide area of the basin,
with 8 ft seas or greater occurring N of 20N between 50W and 70W.
Elsewhere, seas average 4 to 6 ft.

For the forecast, large swells generated from Major Hurricane
Larry, passing well E of the area, will continue to propagate
across area waters. Seas of 8 ft or more can be expected mainly E
of 70W, spreading to 75W Thu, and potentially 80W Thu night. Low
pressure may develop in the NE Gulf of Mexico tonight and cross
the SE U.S. Thu. It could emerge into Atlantic waters Thu night or
Fri. There is some potential of tropical or subtropical
development while the system is in the NE Gulf, and additional
potential off the N Florida or Georgia coast late this week.

$$

Chan
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