[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 250531
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 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 0000 UTC surface analysis and satellite imagery through
0545 UTC.

...SPECIAL FEATURES...

Hurricane Tammy is centered near 24.9N 60.7W at 25/0300 UTC or
500 nm SSE of Bermuda, moving NE at 8 kt. Estimated minimum
central pressure is 976 mb. Maximum sustained wind speed is 75
kt with gusts to 90 kt. Peak seas near the center are estimated
at 26 ft. Numerous moderate to scattered strong convection is
seen within 185 nm of the center in the E semicircle and 70 nm W
semicircle. Scattered moderate convection also extends out well
to the NE of the center, just southeast of a cold front, which
is situated to the north of Tammy. A northward turn is expected
on Wednesday, followed by a slower northwestward motion on
Thursday and Friday. Some additional strengthening is possible
through early Wednesday, followed by weakening through late this
week. Tammy is forecast to become a powerful post-tropical
cyclone by Thursday. 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, now 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 09.5N13W, then continues westward to near 07N30W. The ITCZ
extends from 07N30W to 09.5N39.5W, then continues west of a
surface trough, that runs from 13.5N42W to 07N43W, from 08.5N46W
to 11N57W. Scattered showers and isolated tstorms are found
within 310 nm of the monsoon trough and ITCZ.

...GULF OF MEXICO...

High pressure of 1030 mb over the east coast of United States
extends ridging into the Gulf of Mexico bringing mostly 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 locally 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 producing scattered moderate convection over
the Gulf of Honduras. Additionally, scattered moderate to
isolated strong convection prevails across the western
Caribbean, mainly west of 80W and off the coast of Colombia. A
few showers and tstorms are also noted south of Hispaniola.

High pressure of 1030 mb over the east coast of the United States
is building southward across Cuba. Moderate to fresh NE winds
are present in the NW Caribbean, north of 17N and west of 73.5W,
including in the Windward Passage. Seas are 5 to 7 ft in this
area. 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.

A stationary front extends from 31N55.5W to 25N68W to across the
NW Bahamas to 24N80W. Strong high pressure of 1030 mb over the
east coast of United States follows the front. Hurricane Tammy
lies to the south of the front. Strong to near-gale NE winds and
8 to 13 ft seas prevail behind the frontal boundary, and across
most of the area from 24N to 31N between 64W and 80W. The area
just off NE Florida is experiencing fresh to strong ENE winds
and 6 to 8 ft seas. South of 22N between 60W and the SE Bahamas,
moderate to fresh winds and 5 to 9 ft seas prevail. Scattered
moderate convection is within 250 nm SE of the cold front, to
the NE of Tammy, covering the area from 27N to 31N between 52W
and 60W.

The remainder of the Atlantic, east of 55W, is under the
influence of a 1024 mb high pressure centered near 31.5N28W. Due
to the high pressure, gentle to moderate winds prevail across
the basin east of 55W with seas 5 to 7 ft. The exception is over
the far E Atlantic, east of 21W, from 21N to 30N, where fresh NE
winds and 7 to 8 ft seas prevail.

For the forecast W of 55W, Hurricane Tammy is near 24.9N 60.7W
at 11 PM EDT, and is moving northeast at 8 kt. Maximum sustained
winds are 75 kt with gusts to 90 kt, and the minimum central
pressure is 976 mb. Tammy will move to 26.1N 59.9W Wed morning,
28.1N 59.1W Wed evening, then become extratropical and move to
29.6N 59.7W Thu morning. Tammy will weaken near 30.5N 60.9W Thu
evening, 30.9N 61.8W Fri morning, and 31.3N 62.7W Fri evening.
Tammy will be just SE of Bermuda Sat morning. A cold front
extending from 31N55W to the central Bahamas will stall and
dissipate by Wed. The pressure gradient between this front,
Tammy, and high pressure building N of the area will lead to the
development of a broad area of NE winds and rough seas across
much of the area west of the frontal boundary through the week.

$$
KRV
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