[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121100
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Thu Oct 12 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
1000 UTC.

...SPECIAL FEATURES...

Tropical Depression Sean is near 12.5N 36.7W at 0900 UTC, or
about 885 nm WSW of the Cabo Verde Islands, moving WNW at 10 kt.
Maximum sustained winds are 30 kt with gusts to 40 kt. Minimum
central pressure is 1007 mb. Scattered moderate to strong
convection extends from 10.5N to 14N between 32.5W and 36W, and
remains sheared to the east of southeast of the center by 60 to 90
nm, Scattered moderate isolated strong convection is also noted
west of Sean from 11N to 14N between 39.5W and 44W. Peak seas are
estimated near 11 ft. A west- northwestward or northwestward
track at a slightly slower forward speed is expected during the
next few days. Little change in strength is forecast during the
next few days and Sean is expected to remain under strong vertical
wind shear.

Northern Gulf of Mexico and Western Atlantic Ocean Gale Warning:
Low pressure of 997 mb is centered over the north-central Gulf of
Mexico near 29.5N88W, as of 0600 UTC. A cold front extends from
the low southwestward to 26N91W, and a surface trough continues to
offshore of Veracruz, Mexico. A warm front extends from the low
eastward along 29.5N and across northern Florida. NE to E winds
across the coastal waters NW through NE of the low center and warm
front have diminished below gale force in the past few hours.
However, frequent gusts to gale force continue across the
nearshore coastal waters from the Florida Panhandle to central
Louisiana, and a gale warning remains in effect through sunrise.
Numerous moderate to scattered strong convection occurring
overnight across the NE Gulf of Mexico has shifted inland across
NE Florida and extends into the adjacent Atlantic. Narrow lines of
moderate to strong thunderstorms persist over the Gulf waters,
from the Florida Panhandle and Big Bend region southwestward to
89W. Strong SW winds of 20 to 30 kt are occurring E of the cold
front, and north of 26N to the warm front. These strong winds have
generated very large seas overnight, with recent altimeter data
measuring seas as high as 14 ft off of the mouth of the
Mississippi River, while a large area of 8 to 10 ft and higher
cover most of the waters N of 27N between 86W and 92W. The low
pressure system is expected to move inland over northern Florida
by this morning, with the winds in the Gulf gradually diminishing
through the afternoon.

The low pressure along the frontal system will move into the
western Atlantic today, and gale force winds should develop north
of 30N and east of 75W by late afternoon today, then continue to
shift eastward tonight, and across the northeast offshore waters
Fri through early Sat. Gale-force winds are forecast to affect the
northern offshore waters N of 30N this evening and tonight and
N of 27N Fri through Fri night. Strong thunderstorms and large and
confused seas are expected with this frontal system. As the
system moves E, gale force winds may occur as far south of 27N
between 55W and 65W on Fri. Seas will build to 12 to 18 ft Fri
east of 65W and north of 26N.

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 details on Sean
and the gales in the Gulf of Mexico and Atlantic.

...TROPICAL WAVES...

An eastern Atlantic tropical wave has its axis along 22W from 03N
to 17N, moving westward 10 kt. A broad 1010 mb low (Invest AL94)
is located on the wave near 09N. Scattered moderate isolated
strong convection is within 150 nm NE of the low from 09N to 13N
between 17W and 22W. This activity remains disorganized.
Environmental conditions appear conducive for some slow
development over the next few days. This system should move
westward across the eastern and central tropical Atlantic through
early next week. The system has a low chance of tropical cyclone
formation within the next 48 hours.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis passes through the coast of Senegal near
14N17W to Invest AL94 near 09N23W to 10N30W. The ITCZ extends
from 08N45W to 07.5N47W to 11N58W. Aside from the convection
mentioned in the sections above associated with Sean and AL94,
widely scattered moderate convection is noted from 02.5N to 07N
between 09W and 31W.

GULF OF MEXICO...

Please read the Special Features section for details about the
ongoing gale event over the north-central and northeastern Gulf of
Mexico.

Outside of the gale area, strong S to SW winds prevail over the
eastern Gulf, to the east of the cold front, north of 26N, where
seas are 7 to 11 ft. Fresh to locally strong S winds are over the
SE Gulf, south of 26N to the Yucatan Channel and Straits of
Florida, with seas 6 to 7 ft. To the west of the cold front,
south of the Louisiana coast, northerly winds are still strong
with seas slowly subsiding from a peak of 10-15 ft overnight, now
at 6 t0 10 ft. Gentle to moderate winds and 3 to 5 ft seas are
found over the southwestern Gulf of Mexico. Isolated thunderstorms
are over the SW Gulf of Mexico offshore of Veracruz.

For the forecast, NE gales have ended N of the low and front
early this morning. The low and frontal system will move eastward
and inland across N Florida this morning, accompanied by scattered
to numerous strong thunderstorms and strong winds. Winds and seas
will gradually diminish this afternoon through evening. High
pressure across the Atlantic will build modestly westward into the
eastern Gulf Fri through early Sat, before the next cold front
moves into the NW Gulf Sat morning and across the entire basin by
Sun evening.

CARIBBEAN SEA...

Mid- to upper-level anti-cyclonic flow prevails across most of the
basin, which is leading to subsidence and relatively dry
conditions. The exception is the far SW Caribbean, where scattered
showers and isolated thunderstorms are found south of 13N.

Fresh trades prevail across the central Caribbean between 67W and
76W, locally strong near the coasts of NW Venezuela and NE
Colombia. A large area of fresh to strong SE winds currently
covers the NW Caribbean. Seas are 5-7 ft across the central
Caribbean and 5-8 ft in the NW Caribbean. Moderate winds with 4-5
ft seas are in the far eastern Caribbean.

For the forecast, a weak ridge persists just N of the basin to
the NW Bahamas. Moderate to fresh trade winds across the eastern
and central Caribbean will diminish to gentle to moderate early
Fri and prevail through Mon night as the high pressure shifts
eastward. Fresh to strong SE to S winds in the Gulf of Honduras
and NW Caribbean will continue through Fri night. A cold front
will sink S-SE across the western Atlantic over the weekend and
act to maintain the weak trade wind flow across the basin.

ATLANTIC OCEAN...

Please read the Special Features section for details about
Tropical Depression Sean and on an upcoming western Atlantic gale
event. Please read the Tropical Waves section for details about
Invest-AL94 and the associated tropical wave.

A cold front extends from near 31N46W to 26N53W to 29N64W, where
it transitions to a warm front continuing westward to NE Florida
along 29.5N. To the south, a weak ridge extends from 1014 mb high
pressure near 23N62W to the NW Bahamas. Convection is increasing
across the NW waters near the warm front, where satellite imagery
shows scattered to locally numerous moderate to strong convection
moving off the coast of northern Florida, and across the waters
from 28N to 31N eastward to 75W. Fresh to strong southerly winds
are expanding from offshore of NE Florida, southward to near Cape
Canaveral, while fresh S winds now extends across the SE Florida
coastal waters N of Miami. Seas are 5 offshore of Cage Canaveral
to 9 ft off of Jacksonville, and will build quickly later this
morning as winds increase ahead of the approaching low pressure
system in the Gulf. Gentle to moderate SE to S winds prevail
across much of the Atlantic north of 22N W of 70W, where seas are
4 to 5 ft.

Farther east, a warm front extends from 31N40W northeastward to
low pressure across the central Atlantic. Upper-level diffluence
is supporting scattered moderate to strong convection from 24N to
31N between 37W and 50W. Similar convection is seen within 60 nm
either side of a line extending from 31N25W to 26.5N38W.
Moderate to fresh SW winds and 6 to 7 ft seas are likely
occurring from 26N to 31N between 44W and 56W. A 1015 mb high
pressure is centered near 23N33W, to the north of T.D. Sean.

For the forecast W of 55W, the 997 mb low pressure along the
front in the N Gulf of Mexico is expected to move eastward across
N Florida this morning, then continue eastward and emerge across
the W Atlc, bringing strong to near gale force winds east of
northern and central Florida today, then move E of 75W tonight,
and move eastward across the NE waters Fri through early Sat. Gale
force winds are forecast to affect the northern offshore waters N
of 30N this evening and tonight and N of 27N Fri through Fri
night. Scattered showers and thunderstorms and high seas are
expected with this frontal system. Weak high pressure will prevail
S of 24N through the weekend.

$$
Stripling
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