[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 161126
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Sat Dec 16 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
1040 UTC.

...SPECIAL FEATURES...

Gulf of Mexico, Florida and Western Atlantic Gale Warning and
Significant Swell event: Strong high pressure of 1034 mb across
the Middle Atlantic States, extends eastward toward Bermuda, to
the north of a stationary front that stretches through 24N70W
across the central Bahamas and the Straits of Florida into the
Gulf of Mexico to 1013 mb low pressure near 24N92W. The associated
pressure gradient supports gale-force winds within about 120 nm
north of the front, occurring on either side of southern Florida.
Strong easterly winds extend north of the front to near 30N and
have been blowing in this persistent pattern for 48 hours or so.
this has generated a large area of high seas across both the
Atlantic W of 65W, and across the Gulf of Mexico east of 93W. Buoy
observations and overnight altimeter data showed peak seas of 16
to 19 ft across the central Gulf north of the front. Similar data
overnight across the Atlantic showed peak seas of 14 to 16 ft
across the waters east of the Bahamas. Seas of 12 ft and greater
cover a large area of the Gulf of Mexico this morning, roughly
from 22N to 28N between 85W and 93W. Across the Atlantic waters,
seas of 12 ft and greater currently extend from 23N to 28.5N
between 65W and 79W.

The front will become stationary along 23N across the Atlantic
today and begin to drift northward across the Bahamas this
afternoon and evening, as the low pressure in the Gulf deepens and
moves E-NE across the Gulf, across the Florida Big Bend tonight
and then inland across north Florida early Sun. Gale-force winds
are expected to develop around the low as it moves across central
and NE portions of the Gulf this afternoon through tonight, with
peak seas around 16 ft. As the low deepens across the Gulf, winds
across the Atlantic will become E to SE and strengthen to gale-
force late this afternoon and evening, to the W of 77W, and then
expand eastward to 72W tonight through Sun and increase to 45 kt.
Seas across these NW Atlantic waters will build to 20 ft and
greater tonight through Sun as the gale-force winds expand across
these waters. A cold front associated with this low will move SE
and exit the Gulf of Mexico by Sun morning. Gales will continue
in the western Atlantic into late Mon before lifting north of 31N.

Gale Warning over the North Central Atlantic: An area of low
pressure currently located near 31N52.5W will drift southward
today. Overnight scatterometer data revealed NE gale-force winds
occurring north of the low, and continue within 120 nm north of
the low this morning. Seas are 12 to 16 ft along 30-31N this
morning in NE swell. As the low shifts farther south today, the
associated pressure gradient will gradually weaken, and winds are
expected to fall below gale-force by late afternoon. However, a
broad area of 12 to 16 ft seas will sink southward with the low
and an associated frontal zone, and dominate the waters north of
27N between 43W and 58W through this evening, before subsiding.

Please read the latest NWS High Seas Forecast issued by the
National Hurricane Center at
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough exits the Africa continent near 06N10W and
extends to 06N14.5W. The ITCZ extends from 06N14.5W to 03.5N31W
to 02N50W. Scattered moderate isolated strong convection is
evident from 01N to 07N between 09W and 34W.

...GULF OF MEXICO...

See the Special Features section above for information on the
developing low pressure system across the western Gulf and
associated developing gales. Deep layered low pressure has moved
across the western Gulf tonight and is along 92W, and will aid in
deepening the surface low through tonight. Scattered moderate
isolated strong convection is increasing across the basin E of the
low pressure, from 22N to the North Gulf coasts. The stationary
front extends along about 23N, through the Straits to the low
center, with strong to gale-force winds north of the front to the
Gulf coastal waters.

For the forecast, strong high pressure across the eastern United
States will support strong winds over the northern and eastern
Gulf of Mexico today, with easterly gales offshore of SW Florida
through sunrise. 1013 mb low pressure near 24N92W will move E-NE
across the basin through this evening, and inland across the
Florida Big Bend late Sat night. This will produce additional
gales in the NE Gulf today. Thunderstorms in association with
this low will provide locally higher winds and seas Sat and Sat
night. A cold front will trail from the low, moving SE of the
Gulf midday Sun. Strong north winds will spill into the western
and northern Gulf Sat into Sun behind the front. High pressure
will then settle in over the area through early next week
allowing for marine conditions to improve.

...CARIBBEAN SEA...

Strong high pressure over the Middle Atlantic States extends a
ridge eastward to north of Bermuda. The associated pressure
gradient across the basin is producing fresh to strong NE to E
winds in the lee of Cuba to about 19N, and also from central
Hispaniola to about 14N. Seas are in the 5 to 8 ft range within
these winds, reaching 11 ft in the Yucatan Channel. Moderate to
fresh trades are noted over the south-central Caribbean, including
the Gulf of Venezuela. Elsewhere, gentle to moderate winds
prevail. Seas are generally 4 to 7 ft in the rest of the basin.
Scattered moderate to strong convection is over the NW Caribbean
on the south side of a stationary front located over the SE Gulf
of Mexico. Patches of low level moisture embedded in the trade
wind flow are observed elsewhere producing isolated to scattered
passing showers.

For the forecast, the strong high pressure N of the region will
support fresh to strong trade winds across central portions
through this morning, before the high pressure shifts E and
weakens, causing winds to gradually diminish into Sat night. A
cold front will move through the Yucatan Channel and into the NW
Caribbean Sat night, then stretch from eastern Cuba to Costa Rica
Mon morning, then stall and weaken from central Hispaniola to
Panama Wed. Fresh to strong NW to N winds will follow this front,
becoming N to NE on Wed.

...ATLANTIC OCEAN...

A Gale Warning remains in effect E of southern Florida, between
25N and 27N, including the NW Bahamas. These winds will diminish
below gale-force by afternoon, and then increase again to gale-
force tonight. Please, see the Special Features section for more
information.

Low pressure of 1015 mb has developed along a stalled frontal
boundary overnight, and is currently near 30N52.5W. A cold front
continues SW from the low to near 23.5N66W where it becomes
stationary crossing the central Bahamas and through the Straits
of Florida. Strong to near gale-force NE winds are N of the
stationary front to about 29N and west of 70W. Seas are 12 to 16
ft in association with these winds, highest just E of the
Bahamas. These winds are advecting abundant tropical moisture over
Florida producing intermittent locally heavy showers. As the low
pressure over the Gulf of Mexico and approaches Florida, showers
will become widespread across South Florida and periods of heavy
rain will be possible especially heading into Saturday afternoon
and Saturday night. A second stationary front extends from 31N36W
to 19N42W. This front is attached to an occluded low located N of
area. An area of 8 to 12 ft seas prevails E of this front and N
of 27N. Seas are forecast to subside below 10 ft by late morning.
A deep layer trough over the eastern central Atlantic is
producing scattered showers and a few thunderstorms along and
east of the front, to the north of 28N. The remainder of the
Atlantic S of 27N and E of 60W is under the influence of a weak
ridge, with winds generally moderate to locally fresh, and seas 5
to 8 ft in N to NE swell.

For the forecast, the cold front through the central Bahamas and
Straits of Florida will become stationary along 23N today and
begin to weaken. The pressure gradient between the strong high
pressure building north of the area and the front will result in
near gale to gale-force NE to E winds and high seas over the
waters W of 65W and north of 23N through tonight. Gulf of Mexico
low pressure will move NE across N Florida Sat night, then emerge
along the SE coast of the U.S. on Sun. A large area of southerly
gales will develop SE of the low and an associated cold front Sat
night through Sun night. Numerous thunderstorms in association
with this low will provide locally higher winds and seas this
weekend. Gale-force winds will lift N of the area waters Mon
evening as the cold front reaches from 31N68W to the Windward
Passage, then will stall from 31N65W to Hispaniola Tue night.

$$
Stripling
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