[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 251000
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Wed Oct 25 2023

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
0900 UTC.

...SPECIAL FEATURES...

Hurricane Tammy is centered near 25.6N 60.2W at 25/0900 UTC or
460 nm SSE of Bermuda, moving NE at 9 kt. Estimated minimum
central pressure is 969 mb. Maximum sustained wind speed is 85 kt
with gusts to 105 kt. Peak seas near the center are estimated at
27 ft. Numerous strong convection is noted within 150 nm of the
center in the east semicircle and 120 nm in the west.

Scattered moderate convection also extends out well to the NE of
the center, just southeast of a stationary front, which is
situated to the north of Tammy. A northward turn is expected later
today, followed by a slower northwestward motion on Thursday and
Friday. Some additional strengthening is likely this morning,
followed by weakening through late this week. Tammy is forecast to
become a powerful post-tropical cyclone tonight. Swells generated
by Tammy will continue to affect portions of the Leeward Islands,
the British and U.S. Virgin Islands, and Puerto Rico during the
next couple of days. These swells are likely to cause life-
threatening surf and rip current conditions. Please read the
latest HIGH SEAS FORECAST issued by the National Hurricane Center
at the website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and
the latest Tammy NHC Forecast/Advisory and Public Advisory at
www.hurricanes.gov for more details.

Western Atlantic Very Rough Seas: The tightening pressure
gradient between strong high pressure of 1030 mb over the east
coast of United States and Hurricane Tammy will support a large
area of strong to near-gale force NE winds and very rough seas
of 12 to 17 ft across much of the area from 22N to 31N, between
the east coast of Florida and 60W, through Friday. Mariners
should either seek to avoid this region, or use extreme caution in
this area, depending on your vessel type and cargo. Please read
the latest HIGH SEAS FORECAST issued by the National Hurricane
Center at the website
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details.

...MONSOON TROUGH/ITCZ...

A monsoon trough enters the Atlantic through the coast of Guinea
near 10N13W, then continues westward to near 07N30W. The ITCZ
extends from 07N30W to 10N40W, then continues west of a surface
trough from 09N46W to 11N57W. The surface trough extends from
14N42W to 07N43W. Scattered moderate to isolated strong convection
is noted within 310 nm of these features.

...GULF OF MEXICO...

High pressure of 1030 mb over the east coast of United States
extends ridging into the Gulf of Mexico bringing dry conditions.
Under the influence of this high pressure, fresh E to SE winds and
seas of 4 to 7 ft prevail across the Gulf of Mexico, except for
the eastern Gulf and the Straits of Florida where strong winds
are found.

For the forecast, high pressure north of the area will support
moderate to fresh winds, locally strong in the E Gulf, through
the remainder of the week.

...CARIBBEAN SEA...

Divergence aloft is leading to scattered moderate convection in
portions of the NW Caribbean from 15N to 19N, W of 80W. Scattered
moderate convection is along noted within 90 nm of the Colombian
coast, due to the eastern extension of the east Pacific monsoon
trough.

Continental high pressure over the United States is building
southward toward the northwest Caribbean, and this is leading to
increasing NE winds in the passages and lees of the Greater
Antilles. Fresh to locally strong winds and seas of 5 to 7 ft,
aided in some areas by long period swell from Hurricane Tammy to
the north, are present in these areas. Elsewhere, gentle or
lighter winds and seas of 2 to 3 ft are present.

For the forecast, fresh to occasionally strong winds will prevail
in the NW and north-central Caribbean through the week. Gentle
winds will prevail elsewhere.

...ATLANTIC OCEAN...

Please read the Special Features section at the beginning about
Hurricane Tammy as well as rough seas that are developing over
much of the western basin to the W of Hurricane Tammy.

Aside from the impacts from these two features, to the E of 55W,
high pressure of 1024 mb centered near 31N28W is dominant.

Gentle to moderate winds prevail across the basin east of 55W
with seas 5 to 7 ft. Locally fresh NE winds are occurring offshore
Africa between the Cabo Verde and Canary Islands.

For the forecast W of 55W, Hurricane Tammy is near 25.6N 60.2W at
5 AM EDT, and is moving northeast at 9 kt. Maximum sustained
winds are 85 kt with gusts to 105 kt, and the minimum central
pressure is 969 mb. Tammy will move to 27.0N 59.4W this afternoon,
then become extratropical and move to 28.9N 59.3W Thu morning.
Tammy will reach 30.0N 60.4W Thu afternoon, then weaken near 30.6N
61.6W Fri morning. Tammy will start to move N of the area, to the
SE of Bermuda, Fri afternoon. A stationary front from 31N55W to
the central Bahamas will dissipate today, but the gradient between
Tammy and the decaying front combined with high pressure building
in from the N and W will lead to an increasingly broad area of
strong NE winds and rough seas across much of the area this week,
mainly W of where the frontal boundary currently resides.

$$
KONARIK
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