[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 060004
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Mon Mar 06 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
2345 UTC.

...SPECIAL FEATURES...

Atlantic Significant Swell Event: Long-period NW swell is
currently propagating through the central and eastern waters
generating seas in the range of 12-18 ft north of 26N and
between 35W-65W with a period of 14-16 seconds. This batch of
swell will shift east-northeast through Mon while it subsides.
Just as this happens, yet another set of long-period NW swell
will begin to propagate through the far northern part of the
central waters this afternoon through Mon night, and through a
portion of the eastern part of the area Tue through early on Wed.
The western part of the swell set is forecast to hang up over
the north-central waters Tue night and Wed building seas to a
range of 12-20 ft north of 27N between 47W-65W. By the Thu, the
swell set will be reinforced by a rather massive set of NW to N
swell, with a period of 10-13 seconds that will send seas of 12
ft and greater south to near 21N and E of the Bahamas to roughly
a line from near 31N34W to 21N48W. Mariners navigating across
these waters will encounter hazardous marine conditions.

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

...MONSOON TROUGH/ITCZ...

The monsoon trough is mainly confined to the African continent,
reaching the coast of Liberia near 06N10W. It continues
southwestward to 05N12W, where latest scatterometer data
indicates that it transitions to the ITCZ and continues to 02N20W
to along the Equator to near 49W. Scattered moderate convection
is seen within 180 nm north of the ITCZ between 12W-17W, also
within 180 nm south of the ITCZ between 15W-19W, within 180 nm
north of the ITCZ between 27W-34W,  within 120 nm south of the
ITCZ between 19W-25W and within 120 nm north of the ITCZ between
34W-41W.

...GULF OF MEXICO...

What was previously a stationary front is now analyzed as a
trough from near 27N86W to 26N93W to 24N94W and to the central
Bay of Campeche near 19N94W. An ASCAT data pass shows gentle to
moderate northeast winds west of the trough to near 95W, shifting
to southeast to south in direction east of the trough to near
87W. Some scattered to broken low clouds with possible isolated
showers are seen on satellite imagery from 24N to 29N and between
87W-94W. Otherwise, the remainder of the Gulf is dominated by
generally weak high pressure that is allowing for light to gentle
winds. Seas in the range of 2-4 ft continue over the basin,
except for lower seas of 1-3 ft in the central Bay of Campeche
and SW Gulf.

For the forecast, weak high pressure centered northeast of the
area will dominate early this week, before shifting away, allowing
for a weak cold front to enter the NE Gulf on Wed.

...CARIBBEAN SEA...

The gradient associated to the subtropical ridge between Puerto
Rico and Bermuda continues to support fresh to strong easterly
trade winds across the central and eastern Caribbean Sea. The
strongest winds are noted over the south-central Caribbean and
off NW Colombia. Latest partial ASCAT data received indicates
that gentle to moderate east to southeast winds in the
northwestern part of the Caribbean. Seas of 5-7 ft are over the
waters from 15N to 18N between 68W-85W. Seas of 4-6 ft are north
of 15N between 64W-68W. Seas of 3-5 ft are north of 18N from the
Windward Passage area west to 80W and north of 18N west of 85W.
The highest seas over the basin are in the 7-10 ft range and are
over south-central Caribbean. The lowest seas over the basin are
found north of 18N between 80W-85W.

Satellite imagery shows patches of scattered to occasionally
broken low-level clouds moving westward with possible isolated
showers over the eastern Caribbean from 14N to 17N and east of
68W. Low-level cloud streamers, containing possible isolated
showers, are seen emanating westward off the Lesser Antilles in
the trade wind flow.

For the forecast, the pressure gradient between high pressure
southeast of Bermuda and the Colombian diurnal low will support
strong trades across the south-central Caribbean tonight.
Moderate NE swell will gradually fade across the Tropical
Atlantic waters and northeastern Caribbean passages tonight.
Winds will gradually diminish to below normal basin-wide Tue
through Thu as an Atlantic cold front sinks southward toward the
northeastern Caribbean Sea.

...ATLANTIC OCEAN...

Please read the Special Features section for details on an
ongoing significant swell event. Additional swell events will
continue to impact the Atlantic forecast waters next week.

A weak cold front extends from near 31N59W to 29N68W and to
28N74W, where it becomes a stationary front to near 29N80W.
Latest visible satellite imagery clearly shows a rope-type
cloud marking the leading edge of the front. Overcast to broken
low and mid-level clouds extend about 60 nm to the north of the
rope cloud. Scattered showers are possible with these clouds,
mainly east of 73W. A recent partial ASCAT data pass indicates
fresh to strong southwest to west winds within about 60 to 120 nm
southeast of the from east of 65W. Fresh to strong west to
northwest winds are north of the front. Seas in the range of
8-11 ft are southeast and south of the front to near 28N and
west to 65W. A broad subtropical ridge dominates the remainder of
the forecast waters west of about 39W. High centers of 1019 mb
are located near 23N62W and 22N41W. The associated gradient is
generally supporting light to moderate anticyclonic winds along
with moderate seas.

In the far eastern Atlantic, a cold front enters that part of
the region near 31N30W and continues southwestward to 26N38W,
where it transitions to a weakening stationary front to near
26N45W. A trough out ahead of the front extends from 31N25W to
23N35W. No deep convection is occurring with both of these
boundaries. Scattered to broken low-level clouds with possible
isolated showers are along and near the front and trough. Long-
period NW swell behind the cold front is producing seas of 8-12
ft west to 35W. A significant swell event is underway west of 35W
as described above. Moderate or weaker winds and moderate seas
remain elsewhere.

For the forecast west of 55W, surface ridging extends from the
central Atlantic westward along 24N to the Bahamas. A cold front
that currently extends from Bermuda to Florida will move SE
through Mon, bringing fresh to strong SW winds ahead of it
north of 28N. The ridge will weaken and reform to the northeast
of the Bahamas into Tue as the front dissipates along 25N. Large
NW swell will impact the northeast waters behind the front
tonight through Tue night, then large N to NE swell will move
south of 31N and spread across all Atlantic waters into Thu night
with the next frontal system approaching from the north. Gale
conditions are expected by Tue night across the northeast portion
or the area. Seas will peak to 20 ft near and north of 30N57W on
Wed.

$$
Aguirre
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