[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 180932
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Wed May 18 2022

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
0915 UTC.

...SPECIAL FEATURES...

Global models suggest that a Central American Gyre event
will impact the western Caribbean and shift across Central
America late this week into the weekend. Climatologically, this is
the favored time of year for these broad low pressure areas to
develop. CAG's increase SW monsoon flow, and lift the monsoon
trough well north of its typical position, which advects abundant
moisture northward. This CAG will bring an increase in convection,
starting over southern portions of Central America, before
gradually moving north. Expect locally heavy rainfall over
portions of Central America, especially in mountainous terrain.
Please refer to products issued by your local weather service for
more information.

...TROPICAL WAVES...

A tropical wave is analyzed with axis along 32W and south of 11N,
moving west at 15 kt. A recent ship observation and earlier scatterometer
data revealed a weak surface signature and no significant
convection is evident at this time near the wave axis.

A tropical wave is in the southwest Caribbean with axis along
78W/79W and south of 17N, moving west-northwest at 15-20 kt. This
position corresponds with an area of enhanced moisture seen on
layered precipitable water imagery. Scattered moderate to isolated
strong convection is evident south of 11N between 76W and 78W.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Senegal near 16N17W
to 10N25W. The ITCZ is analyzed west of a tropical wave from
01N34W to the mouth of the Amazon River near the equator and 50W.
Scattered moderate to strong convection is noted from 06N to 10N
between 11W and 15W. Scattered moderate convection is also evident
from 01N to 04N between 42W and 48W. south of 11N between 76W and
78W.

GULF OF MEXICO...

1017 mb high pressure is centered near 26N95W in the north-central
Gulf. Buoy data and a recent scatterometer satellite pass is
showing moderate to fresh SE winds off the south Texas and
northern Tamaulipas coasts, between the high pressure and lower
pressure over the Central Plains. Farther south, a ship
observation confirms fresh to strong NE winds off the western
coast of Yucatan, related to a trough that sets up most night over
the Bay of Campeche. Light to gentle breezes are noted elsewhere
over the eastern Gulf. Seas are 2 to 4 ft over the western Gulf,
and 1 to 2 ft over the eastern Gulf. No significant shower or
thunderstorm activity is evident.

For the forecast, the high pressure over the central Gulf will
maintain gentle to moderate to fresh S to SE winds over the
western half of the basin and light to gentle variable wind across
the eastern Gulf into mid week. Moderate to fresh SE winds will
continue over the western Gulf through Sat, expanding to the
eastern Gulf Thu night through Sun as low pressure develops along
Central America and the Bermuda High extends into portions of the
E Gulf. Meanwhile fresh to occasionally strong NE winds will pulse
off the western Yucatan peninsula mainly at night through the
week.

CARIBBEAN SEA...

Please see the Special Features section for information on a
potential heavy rainfall event.

A recent scatterometer satellite pass confirmed fresh to strong
trade winds pulsing off the coast of northwest Venezuela and
northeast Colombia. Elsewhere, the gradient between high pressure
in the Atlantic and lower pressure over South America is
maintaining moderate to fresh easterlies in the eastern Caribbean
with gentle to moderate winds in the central Caribbean. Light to
gentle winds are west of a surface trough along 82W/83W. Seas are
5 to 7 ft across the basin, except 2 to 4 in the northwest
Caribbean. Other than the previously discussed shower and
thunderstorm activity near the tropical wave, no significant
shower or thunderstorm activity is noted.

For the forecast, the surface ridging over the western Atlantic
will continue to support moderate to fresh trade winds across the
east and central Caribbean through mid week, with fresh to strong
winds pulsing off Venezuela and northwest Colombia. Winds and seas
across the basin may increase through late week as the ridge
strengthens and broad low pressure forms along Central America.
Strongest winds expected to be over the northwest and south-
central Caribbean Thu night through the remainder weekend.

ATLANTIC OCEAN...

The subtropical ridge reaches from 1023 mb high pressure centered
near 26N48W westward 25N70W. The ridge is shifting eastward ahead
of a weak frontal boundary moving eastward over the waters between
the Carolinas and Bermuda. This pattern is supporting gentle to
moderate winds north of 20N west of 55W with 4 to 6 ft seas in
open waters.

In the central Atlantic, the dominant ridge north of 20N is
supporting light to gentle winds north of 25N and moderate to
fresh south of 25N. Seas are generally 6 to 8 ft in Ne to E
swell. In the eastern Atlantic, moderate to fresh northerly winds
are observed along the coast of Morocco and NE of the Cabo Verde
Islands. Seas are generally 6 to 8 ft.

For the forecast west of 55W, the surface ridge along 25N is
shifting east ahead of a weak cold front moving eastward to the
north of 30N through Wed. Weak ridging will build again over the
region later in the week, supporting gentle to moderate winds
through Sat night, except for moderate to fresh winds north of
Hispaniola and the Great Bahama Bank Fri night through Sun night.

$$
Christensen
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