[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 151809 CCA
TWDAT

Tropical Weather Discussion...Corrected
NWS National Hurricane Center Miami FL
1805 UTC Wed Feb 15 2023

Corrected Caribbean Sea section

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
1745 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. Gale-force winds are forecast to develop offshore
Tampico, Mexico, Thu evening then spread S to off the coast of
Veracruz, Mexico overnight on Thu. The gale-force winds in the
western Bay of Campeche will persist into Fri night. Seas in this
area will build to near 17 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 06N16W, where latest
scatterometer data indicates that it transitions to the ITCZ and
continues to below the Equator near 25W. Scattered moderate
convection is from 03N to 08N between 09N1-15W, and also within
120 nm S of the ITCZ between 15W-20W.

...GULF OF MEXICO...

Please see Special Features above for details on an upcoming
Gale Warning for portions of waters offshore Mexico, where gales
will develop starting Thu afternoon.

The western extension of the Atlantic subtropical ridge reaches
westward to the northern section of the central Gulf per the
12Z analysis. The gradient between the ridge and relatively lower
pressure in the Southern Plains is maintaining moderate to fresh
southeast winds over the basin. Seas are 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 are 3-5 ft in the southeastern Gulf.
Visible GOES-E imagery shows patches of fog, some dense producing
reduced visibilities, hugging the coast of Mexico from near Poza
Rica, northward to near Galveston, Texas. The fog is expected to
gradually diminish during the early afternoon. With favorable
conditions returning tonight, the fog is expected to once again
develop over roughly the same Gulf areas as this morning.
Otherwise, scattered small-type low clouds, moving northward with
to the moderate to fresh southerly wind flow, are noted between
83W-87W and from 22N to 30N between 87W-95W.

For the forecast, the Atlantic subtropical will continue to
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. Strong to near gale
force N winds as described above also expected behind the front
Thu into early Sat. Conditions will improve Sat into Sun.

...CARIBBEAN SEA...Corrected

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 are inhibiting convection from forming. Only
isolated showers moving westward in the trade wind flow are
noted primarily S of 20N. The weather pattern is presently being
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 S 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. Seas are 4-7 ft in the basin, except for higher
seas of 6-8 ft from 15N to 18N between 72W-76W, 7-11 ft from 11N
to 15N between 72W-80W outside the gale conditions and lower
seas of 3-5 ft in the northwest section of the sea. Seas are 4-6
ft in the Gulf of Honduras.

For the forecast, a strong pressure gradient will persist across
the south central Caribbean Sea through the forecast period,
supporting fresh to strong easterly trade winds. Trade winds will
pulse to gale force off the coast of Colombia each night 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 31N50W to 23N61W, where satellite
imagery indicates that it is dissipating and continues to near
21N70W. The imagery shows areas of rain with embedded scattered
showers and thunderstorms within 150 nm SE of the front N of 26N.
Scattered showers and isolated thunderstorms are within 120 nm SE
of the front from 25N to 26N. Scattered showers moving WSW are
possible along the weakening part of the front. Fresh N winds
follow the cold front for about 300 nm, before diminishing in
association with a 1028 mb high center located N of the area.
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.
To the W of the high, offshore Florida, fresh SE winds are noted.
Seas N of 25N between the front and 68W are 8-12 ft due to a
long- period NW to N swell, with 5-7 ft seas elsewhere behind the
front, except for 3-4 ft N and W of the Bahamas. For waters to
the S and E of the aforementioned cold front N of 20N and W of
35W, gentle to moderate mainly S winds prevail along with seas of
5-7 ft. Seas in this area are in the 8-11 ft range.

Latest ASCAT data over the far eastern Atlantic indicates that
fresh to strong NE to E winds are present N of 09N and E of 33W.
Seas within this area of winds are 8-12 ft due to mixed NE and NW
swell.

In the tropical Atlantic S of 20N between 35W and the Lesser
Antilles, moderate to fresh trades prevail along with seas of 8-10
ft in NE to E swell.

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 the time of year.

For the forecast W of 55W, the aforementioned cold front will
continue moving eastward, exiting the basin tonight. The portion
of the front that is weakening will most likely soon transition
to a shear line. Otherwise, a building ridge north of the area
will strengthen the trades south of 25N tonight into Fri night,
with seas in this zone increasing to a peak of about 11 ft.

$$
Aguirre
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