[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 102327
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Sat Mar 11 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...

Central Atlantic Gale Warning: A stationary front extends from
31N36W to 16N60W. Strong NW to W winds behind the front prevail
north of 25N. These winds will shift eastward through this evening
and strengthen to gale force N of 29N, then gradually lift north
of the area Sat morning. Currently, seas up to 17 ft are found
ahead and behind the frontal boundary. A 2130 UTC Altika altimeter
pass measured seas to 17 ft at 30N51W. Large NW to N swell covers
the majority of the west and central subtropical North Atlantic.
Seas in excess of 12 ft are currently observed between 30W and
70W, reaching as far south as 22N. Seas in the area of gale force
winds will build to 18 ft by this evening. The swell from this
event will continue to propagate SE and gradually abate through
the weekend.

SW Atlantic Gale Warning: A cold front will enter the offshore
waters of the SE United States this evening and move eastward
over the next few days. A strengthening low pressure system north
of the area and tightening pressure gradient will support strong
to near gale force winds ahead and behind the frontal boundary,
mainly north of 25N. Gale force winds will develop ahead of the
frontal boundary early Sat morning through Sun, primarily north of
28N. Seas will quickly build to near 13 ft Sat ahead of the front
and to near 23 ft by Sun behind the front. Seas greater than 12
ft will remain north of 25N. Winds and seas will abate early next
week.

Please read the latest High Seas Forecast at
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details
on the gale and swell events.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic through the coast of
Sierra Leone near 07N13W to 05N14W. The ITCZ extends from 05N14W
to 01N50W. Scattered moderate and isolated strong convection is
observed south of 05N east of 22W.

GULF OF MEXICO...

A weak cold front extends from the Florida panhandle to 28N95W
where it becomes stationary to the S Texas coastline. Scattered
moderate convection is noted north of 29W between 85W-90W. Overall,
a weak 1017 mb high pressure at 27N91W dominates the basin
maintaining fairly tranquil weather conditions. Light to locally
strong anticyclonic winds and seas of 2-4 ft prevail.

For the forecast, the cold front will cause moderate northerly
winds at the northeastern Gulf through tonight. Another cold front
is forecast to approach the northern Gulf late Sat night and Sun,
inducing moderate southerly flow across the entire Gulf. It
should enter the northern Gulf Sun night, then sinks southward
through Tue. In response, fresh to strong with locally near-gale
northerly winds are expected behind the front for much of the
Gulf. This front is going to move southeast of the region near
midweek.

CARIBBEAN SEA...

A shear line extends from just south of Hispaniola to the Leeward
Islands. No deep convection is associated with this feature. In
the remainder of the Caribbean Sea, except for a few shallow
patches of moisture, relatively dry air dominates. A weak pressure
gradient sustains light to moderate easterly winds across the
basin. Seas in the 3-6 ft range prevail across the Caribbean,
except for the Mona and Anegada Passages where 6-8 ft seas due to
N swell are occurring.

For the forecast, the shear line should dissipate tonight.
Easterly winds at the waters just north of Colombia will pulse to
between strong and near-gale force during night times through Sun
night. Fresh to strong ESE winds are expected at the the Gulf of
Honduras late Sat night through Tue morning. Moderate long-period
northerly swell will continue to impact the eastern basin,
including waters near Puerto Rico and the Virgin/Leeward Islands
for the next several days. Looking ahead, a cold front is forecast
to enter the northwestern basin near midweek next week, which
will bring fresh to strong NE winds and rising seas.

ATLANTIC OCEAN...

Please read the Special Features section for details on a gale
warning and associated high seas across the Atlantic forecast
waters this week.

A stationary front extends from 31N36W to 16N60W. Scattered
moderate convection is seen ahead of the frontal boundary, north
of 25N and west of 33W. Fresh to strong southerly winds are
evident on scatterometer satellite wind data ahead of the cold
front, north of 20N and west of 30W. Fresh to near gale westerly
winds are also present behind the frontal boundary, mainly north
of 23N and east of 68W. Seas are 10-17 ft in the areas described,
with the highest seas occurring near 29N57W and 31N35W.
Elsewhere, the pressure gradient is increasing off NE Florida as a
low pressure and frontal boundary approaches the region,
resulting in fresh to strong southwest winds north of 29N and
west of 77W. Seas in these waters are 4-7 ft. Light to moderate
winds and moderate seas prevail in the rest of the tropical
Atlantic due to an expansive subtropical ridge.

For the forecast W of 55W, the stationary front should gradually
dissipate through Sat evening. A reinforcing cold front is forming
from 31N48W southwestward to 26N62W this afternoon. This feature
will keep fresh to strong with locally near-gale winds north of
24N and east of 63W through late tonight. Meanwhile, another cold
front is exiting into the Atlantic waters from the southeast U.S.
coast this afternoon. It will reach from 31N70W to southern
Florida early Sat morning, generating strong to near-gale westerly
winds and higher seas from the northwest Bahamas northward. As it
moves farther eastward across the western Atlantic waters, it
will produce near-gale to gale winds north of 27N and east of 72W
through Sun. Successive large northerly swell behind these fronts
are going to persist across the western Atlantic through midweek
next week.

$$
Landsea/Delgado
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