[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 152320
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Thu Feb 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 1800 UTC surface analysis and satellite imagery through
2300 UTC.

...SPECIAL FEATURES...

Caribbean Sea Gale Warning: The induced pressure gradient due to
the combination of a 1028 mb high center that is north of the
area, with comparatively lower pressure in the south-central
Caribbean Sea and in Colombia is expected to support fresh to
strong NE to E trade winds along with seas of 8-11 ft. The
pressure gradient will tighten just enough at night through the
weekend allowing for these winds to pulse to gale-force. As this
happens, seas with these winds are expected to build slightly
higher to about 10-13 ft.
Please read the latest High Seas
Forecast at https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more
details.

Gulf of Mexico Gale Warning: A strong cold front will emerge off
Texas coast Thu morning. Strong to near gale force N winds can
be expected behind the front in the western and central Gulf Thu
into early Sat. Gales will develop offshore Tampico, Mexico, Thu
evening, spreading S to off the coast of Veracruz, Mexico,
overnight Thu. The gales in the western Bay of Campeche will
persist into Fri night. Seas in this area will build to near 16
ft by Fri afternoon. Conditions will improve Sat into Sun.
Please read the latest High Seas Forecast at
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends from the coastal plains of Sierra
Leone near 08N13W southwestward to 05N17W. The ITCZ continues to
below the Equator near 25W. Scattered moderate convection is
from the equator to 03N between 13W-22W.

...GULF OF MEXICO...

A Gale Warning is in effect for portions of the offshore waters
of Mexico. Please, see the Special Features section above for
details.

A ridge dominates the Gulf waters anchored by a 1028 mb high
located W of Bermuda near 32N67W. The pressure gradient between
the ridge and low pressure across the Southern Plains is
maintaining moderate to fresh southeast winds over the basin.
Seas are generally in the range of 4-6 ft, except for slightly
higher seas of 5-7 ft in most areas of the western Gulf. Seas
are 3-5 ft in the southeastern Gulf. Scattered small-type low
clouds, moving northward with to the moderate to fresh southerly
wind flow, are noted over parts of the Gulf.

For the forecast, the Atlantic subtropical ridge will gradually
shift eastward over the next few days. Fresh to strong winds will
continue in the Gulf of Mexico in advance of the next cold front,
which will emerge off Texas Thu morning. Gales will develop offshore
Tampico, Mexico, spreading S to off the coast of Veracruz, Mexico.
Please, see the Special Features section for more details.

...CARIBBEAN SEA...

Please read the Special Features section above for details on a
Gale Warning that is in effect for the coastal waters offshore
Colombia.

Ample subsidence aloft throughout the basin and associated dry
sinking air is inhibiting convection from forming. Only isolated
showers moving westward in the trade wind flow are noted across
the basin. The weather pattern is dominated by the Atlantic
subtropical ridge. The associated gradient is resulting in
generally fresh to strong NE to E trade winds throughout the
basin, except in the south-central Caribbean where mainly strong
trades prevail and within about 60 nm S of Hispaniola. A recent
ASCAT pass revealed strong to near gale-force NE to E trade
winds within 75 nm of the coast of northwestern Colombia. Fresh
SE winds are in the far western Caribbean Sea, with fresh to
strong SE winds in the Gulf of Honduras. Seas are 8-10 ft near
the coast of Colombia, and 6-8 ft over the remainder of the
central Caribbean. Seas are generally 4-6 ft elsewhere.

For the forecast, a persistent subtropical ridge north of the
area will sustain fresh to strong easterly trades through the
forecast period. Winds will pulse nightly to gale force off the
coast of Colombia into early next week. Elsewhere, large NE to E
swell with seas to 10 ft is over the tropical N Atlantic. Winds
and seas in this region will slowly diminish through tonight.
However, a new area of northerly swell will enter the tropical
Atlantic Thu, persisting into the weekend. Winds will increase to
strong speeds east of the Leeward Islands Thu night into Sat.

...ATLANTIC OCEAN...

A cold front stretches from near 31N48W to 23N58W, where
satellite imagery indicates that it is dissipating and continues
to near 21N73W. Scattered showers with embedded thunderstorms are
noted on satellite imagery within about 150 nm SE of the front N
of 25N. Isolated showers are possible along the weakening part
of the front. Fresh N winds follow the cold front to about 60W
based on the most recent scatterometer data. Moderate to fresh
NE to E winds are N of the weakening part of the front, while
gentle to moderate NE winds are to its S. Seas of 8-12 ft in long
period NW swell are in the wake of the front, mainly N of 25N
and E 64W. Seas of 6-7 ft are noted elsewhere behind the front.
the remainder of the Atlantic forecast area is under the
influence of 1033 mb high pressure located over the southern
Azores. The pressure gradient between this system and lower
pressures in the vicinity of the ITCZ is resulting in a large
area of fresh to strong trade winds S of 25N E of 50W. Fresh to
strong northerly winds are also observed between the above
mentioned high pressure and a 1015 mb low pressure located E of
the Madeira Islands near 33N13W. Seas are 8 to 11 ft E of 35W due
to mixed NE and NW swell. In the tropical Atlantic S of 20N
between 50W and the Lesser Antilles, moderate to fresh trades
prevail along with seas of 6-8 ft.

Satellite imagery reveals the presence of an extensive plume of
Sahara Air Layer (SAL) dust in the far eastern Atlantic east of
about 26W. Recent surface observations from along the coast of W
Africa are reporting blowing dust and sand. This observation of
the SAL is quite early for this time of year.

For the forecast W of 55W, the aforementioned frontal boundary
will continue moving eastward, exiting the basin tonight. A
building ridge north of the area will strengthen the trades south
of 25N tonight into Sat, with seas in this zone increasing to 11
ft. A cold front is forecast to enter the Gulf on Thu and will
reach the waters off NE Florida late Fri. This will support
strong winds ahead and behind the frontal boundary Fri night into
Sat as the frontal boundary moves eastward, mainly N of 28N.
Also, a low pressure will develop this weekend along the
weakening cold front in the eastern waters and the gradient
between the low and the ridge will sustain strong NE winds N of
24N and E of 50W. Seas will build to 12 ft by Sat.

$$
GR
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