[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 182142
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Thu Oct 19 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 1800 UTC surface analysis and satellite imagery through
2100 UTC.

...SPECIAL FEATURES...

Newly formed Tropical Storm Tammy is centered near 13.0N 51.7W at
18/2100 UTC or 540 nm E of the Windward Islands, moving W at 20
kt. Estimated minimum central pressure is 1007 mb. Maximum
sustained wind speed is 35 kt with gusts to 45 kt. Peak seas are
currently around 15 ft. Numerous moderate isolated strong
convection is noted from 06N to 15N between 44W and 54W, and
extending from 13N to 15N between 33W and 44W. A westward motion at
a slower forward speed is expected through Thursday.  A turn toward
the west-northwest is forecast by Thursday night, followed by a turn
toward the northwest Friday night or Saturday. On the forecast
track, the center of Tammy will move near or over the Leeward
Islands Friday and Saturday. Gradual strengthening is forecast
during the next couple of days. Swells generated by Tammy will
begin affecting portions of the Lesser Antilles on Thursday.
These swells are likely to cause life-threatening surf and rip
current conditions. Please consult products from your local
weather office. Heavy rains from Tammy will begin to affect the
northern Windward and Leeward Islands on Friday, spreading into
the British and U.S. Virgin Islands and Puerto Rico over the
weekend. This rainfall may produce isolated flash and urban
flooding, along with isolated mudslides in areas of higher
terrain. Please read the latest HIGH SEAS FORECAST issued by the
National Hurricane Center at 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.

...MONSOON TROUGH/ITCZ...

The monsoon trough reaches the Atlantic through the coast of
Senegal 13N17W to 10N20W to 03N39W. The ITCZ extends from 03N39W
to NE of the coast of Brazil near 02N49W. Numerous moderate
isolated strong convection is noted within 270 nm either side of
the monsoon trough between 19W and 30W, and from 02N to 07N
between 32W and 38W.

...GULF OF MEXICO...

A few related areas of high pressure across the SE United states
with a ridge extending across the northern Gulf of Mexico coastal
plain. Gentle to moderate anticyclonic flow is found across the
basin waters N of 26N, with moderate to locally fresh easterly
flow S of 26N. Seas are 1-3 ft across the NW half of the basin,
and 3-5 ft across the SE half. Otherwise, a weak surface trough is
analyzed in the western Bay of Campeche offshore Veracruz with
little fanfare.

For the forecast, high pressure will continue to dominate the
Gulf waters through Thu night. Gentle to moderate anticyclonic
winds will prevail through Thu night. A frontal system will bring
fresh winds to the NE Gulf Fri and Fri night. Benign conditions
will then return over the weekend as high pressure builds back in.

...CARIBBEAN SEA...

Please see the SPECIAL FEATURES section above for more details
on newly formed Tropical Storm Tammy.

A stationary front extends from eastern Cuba to NE Honduras.
Scattered moderate to strong convection is within 90 nm NW of the
front, and S of the front to 11N between Jamaica and Nicaragua, as
well as across the tip of eastern Cuba. Fresh to strong NE winds
are noted S of 20N and west of the front per an earlier ASCAT
scatterometer pass, along with seas of 4-7 ft. Fresh to strong
trades are noted in the S-central Caribbean along with 4-6 ft
seas. Mainly moderate trades and 3-5 ft seas prevail elsewhere SE
of the front, except 1-3 ft in the SW Caribbean.

For the forecast, Tammy will move to 13.1N 53.7W Thu morning,
13.5N 55.9W Thu afternoon, 14.1N 58.2W Fri morning, 15.0N 60.2W
Fri afternoon, 15.9N 61.7W Sat morning, and 17.5N 62.7W Sat
afternoon. Tammy will change little in intensity as it moves to
near 21.4N 63.4W Sun afternoon. A stationary front extends from
eastern Cuba to NE Honduras. The front should remain in place
through tonight before dissipating on Thu. Fresh to locally strong
NE winds and seas of 8 ft will persist over the northwest
Caribbean W of the front through tonight as high pressure builds
over the area.

...ATLANTIC OCEAN...

Please see the SPECIAL FEATURES section above for more details
on newly formed Tropical Storm Tammy.

A stationary front remains draped across the western Atlantic from
31N63W to across the SE Bahamas to eastern Cuba. Scattered
moderate to isolated strong convection is noted within 60-120 nm
either side of the front. Winds across the same area of the
convection W of the front are fresh to strong. Mainly moderate NE
winds are elsewhere W of the front, along with 3-5 ft seas. A
surface trough extends from 31N58W to N of the Mona Passage near
20N65W. Numerous moderate isolated strong convection is noted
within 90-150 nm NW of the trough N of 22N.

An upper-level low east of the Lesser Antilles is producing
scattered to isolated strong convection from 15N to 24N between
52W and 61W. Fresh to locally strong easterly winds are within
this convection, along with 7-10 ft seas.

Farther east, 1021 mb high pressure is analyzed near 30N45W.
Mainly light to gentle winds are under the ridge from 27N to 31N
between the Canary Islands and 55W. Mainly moderate trades prevail
elsewhere outside of the influence of Tammy. Seas are 5-7 ft
across the remainder of the open waters, except 4-5 ft S of 20N
and E of 30W, and within 240 nm NE of the coast of NE South
America.

For the forecast W of 55W, Tammy will move to 13.1N 53.7W Thu
morning, 13.5N 55.9W Thu afternoon, 14.1N 58.2W Fri morning,
15.0N 60.2W Fri afternoon, 15.9N 61.7W Sat morning, and 17.5N
62.7W Sat afternoon. Tammy will change little in intensity as it
moves to near 21.4N 63.4W Sun afternoon. A stationary front
extends from 31N63W to eastern Cuba. The front will remain in
place before dissipating Thu. High pressure will build over the
area in the wake of the front. The next frontal system will move
offshore the southeastern United States Fri night. Fresh to strong
winds and rough seas are forecast north of 27N Fri night through
Sat night with this system.

$$
Lewitsky
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