[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 011100
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Fri Oct 1 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 1200 UTC surface analysis and satellite imagery through
1045 UTC.

...SPECIAL FEATURES...

Hurricane Sam is centered near 26.6N 61.7W at 01/0900 UTC or 380
nm SSE of Bermuda moving NNW at 15 kt. Estimated minimum central
pressure is 934 mb. Maximum sustained wind speed is 130 kt with
gusts to 160 kt. The eye is 20 nm in diameter. Numerous moderate
scattered strong convection extends outward from the center 150 nm
in the N semicircle and 90 nm S semicircle. Scattered moderate
convection is elsewhere within 240 nm N semicircle. Maximum
significant wave height near the center is estimated at 42 ft.
On the forecast track, the center of Sam will pass well to the
east of Bermuda tonight. Although fluctuations in intensity are
still possible today, weakening is forecast during the next couple
of days. However, Sam is expected to remain a major hurricane
through at least Saturday night. 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 NHC
Forecast/Advisory and Public Advisory at www.hurricanes.gov for
more details.

Tropical Storm Victor is centered near 11.7N 32.3W at 01/0900
UTC or 550 nm WSW of the Cabo Verde Islands moving NW at 13 kt.
Estimated minimum central pressure is 997 mb. Maximum sustained
wind speed is 50 kt with gusts to 60 kt. Numerous moderate
scattered strong convection is within 180 nm of the center in the
northern semicircle. Scattered moderate convection is within 180
nm SE quadrant. Maximum significant wave height near the center is
estimated to be near 18 ft. A motion toward the west-northwest
and northwest is expected today, followed by a northwestward
motion over the eastern tropical Atlantic over the weekend. Some
slight strengthening will be possible through tonight, followed
by a slow weakening trend over the weekend. Please read the
latest High Seas Forecasts issued by Meteo-France at website
http://weather.gmdss.org/II.html and by the National Hurricane
Center at website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml as
well as the latest NHC Forecast/Advisory and Public Advisory at
www.hurricanes.gov for more details.

...TROPICAL WAVES...

A tropical wave axis extends along 52W from 05N to 16N, moving W
at 15-20 kt. Isolated showers and tstorms are noted along and east
of the wave axis from 08N-11N.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the W coast of Mauritania near
18N16W to 11N25W, then resumes W of Victor from 08N34W to 06N39W.
The ITCZ extends from 06N39W to 06N49W, then resumes W of a
tropical wave from 07N52W to 07N58W. Aside from the convection
associated with Victor and the tropical wave, scattered moderate
to strong convection is noted from 07N-12N, within 120 nm of the
west coast of Africa. Scattered showers are seen from 05N-11N
between 37W-48W.

GULF OF MEXICO...

Ample moisture noted in Total Precipitable Water imagery over
the western Gulf is leading to scattered moderate showers and
isolated tstorms. However, a mid- to upper-level ridge centered
over the SW Gulf of Mexico is acting to suppress the coverage
and intensity of these showers and storms. A recent ASCAT pass
shows mainly moderate E winds across the basin. Seas are 2-4 ft
over the western Gulf and 1-3 ft across the eastern Gulf.

For the forecast, a weak ridge of high pressure will persist
north of the Gulf through tonight, supporting tranquil
conditions. Stronger higher pressure will build across the
region by Sun, allowing winds and seas to increase over the SE
Gulf over the weekend. A weak cold front should move across the
Gulf on Mon and Tue, but with little enhancement of the winds
and seas.

CARIBBEAN SEA...

An upper level trough extending from the W Atlantic to the SW
Caribbean continues to support scattered showers and isolated
tstorms between the Isle of Youth and Puerto Rico, including the
Cayman Islands, Jamaica and Hispaniola. Showers and tstorms are
also noted along the N coast of Venezuela and Colombia. A recent
ASCAT pass shows gentle trades across the basin, with moderate
winds in the south-central Caribbean. Moderate to locally fresh
NE winds are in the Windward Passage. Seas of 2-4 ft prevail
over much of the basin, except 1-2 ft in the NW Caribbean. Swell
from Hurricane Sam is affecting the NE Caribbean passages from
the Mona Passage to the northern Leeward Islands. The swell will
begin to gradually subside later today.

For the forecast, tranquil trades will continue over the
Caribbean through today. As high pressure builds in behind
Hurricane Sam, winds are expected to become moderate to fresh
across the central and E Caribbean beginning Sat and continuing
through mid week.

ATLANTIC OCEAN...

Refer to the section above for details on Hurricane Sam and T.S.
Victor.

The Cumbre Vieja volcano on the island of La Palma in the Canary
Islands near 28.6N 17.8W has been erupting since September 19th.
High concentration of volcanic ash is found near the volcano.
Marine and aviation interests should monitor this ongoing
situation by reading the latest Volcanic Ash Advisory issued by
Meteo-France at http://vaac.meteo.fr/volcanoes/la-palma/ for
details.

An upper-level trough over the W Atlantic, to the west of
Hurricane Sam, is supporting a weak frontal boundary along 30N
between 70W-77W, but this front will be dissipating later today.
Scattered showers and isolated tstorms are seen over the central
and NW Bahamas and east of Florida. A 1029 mb high pressure over
the Azores dominates the Atlantic to the east of Sam. ASCAT shows
fresh to strong trade winds from 15N-25N between 28W-41W, and from
the Madeira and Canary Islands westward to 28W.

For the forecast, Hurricane Sam will move to near 30N62W this
evening and to near 33N 60.5W Sat morning. Large swell from Sam
will impact the area northeast of the Bahamas today through
Saturday, then gradually subside Saturday night through Sunday.
Seas up to 12 ft will reach as far west as about 72W, and 10 ft
seas will make it to 77W, due to swell from Sam. After that
time, stronger high pressure will build into the area, which
will bring moderate to occasionally fresh winds to the western
Atlantic early next week.

$$
Torres
This weather bulletin was brought to you by:
www.nashvilleweather.net