[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 130503
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Sat Aug 13 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 0000 UTC surface analysis and satellite imagery through
0450 UTC.

...TROPICAL WAVES...

A tropical wave is analyzed with axis along 20W from 05N-20N,
moving W at 5-10 kt. A 1008 mb low pressure is along the wave
axis near 14N20W. Isolated to scattered moderate convection is
noted from 12N-20N between 22W and the west coast of Africa.
Scattered showers are seen from 05N-10N between 13W-22W.

A tropical wave extends its axis from 23N52W to 06N50W, moving W
at 15-20 kt. A broad surface trough is associated with this
tropical wave. A large plume of atmospheric moisture accompanies
this wave, as noted in Total Precipitable Water imagery. Scattered
showers and isolated thunderstorms are occurring along and within
360 nm E of the wave axis.

A weak tropical wave has an axis over the eastern Caribbean along
62W from 20N southward to SE Venezuela, moving W at 10-15 kt.
Isolated showers are noted from 10N-12N between 61W-64W, including
over Trinidad.

A central Caribbean tropical wave has an axis along 75/76W from
eastern Cuba to western Colombia, moving W at 10-15 kt. Isolated
moderate convection is over Haiti, eastern Cuba and Jamaica.
Father south, scattered moderate convection prevails over northern
Colombia and waters south of 13N between 71.5W-77W, near where the
wave intersects the east Pacific monsoon trough.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of southern Mauritania
near 17N16W to a 1008 mb low near 14N20W to 11N26W to 14N47W to
10N60W. Aside from the convection described in the Tropical Waves
section above, scattered moderate isolated strong convection is
noted from 07N-11N between 22W-35W.

GULF OF MEXICO...

A surface trough of low pressure extends over the northwest Gulf
of Mexico from 29N91W to 25N96W. The coverage of showers and
thunderstorms has died down overnight compared to the daytime on
Friday. Isolated showers are covering the central and north-
central Gulf, to the east of the trough axis. A 1017 mb high
pressure is centered over the NE Gulf near 28N85W. Gentle winds
prevail across most of the Gulf, except for moderate near the
surface trough and over the Bay of Campeche. Recent buoy and
altimeter data across the basin are showing seas of 2 to 3 ft.
However, seas up to 4 ft may be occurring just east of the surface
trough in the northern Gulf, and to the west of the Yucatan
Peninsula.

For the forecast, low pressure is likely to reform along the
surface trough in the NW Gulf later this morning. This system will
drift west-southwestward and approach the Texas coast this
afternoon, and move inland over southern Texas on Sun. This system
is expected to produce scattered to numerous showers and
thunderstorms today through tonight over the northwest Gulf.
Strong gusty winds and rough seas can be expected with this
activity. Weak high pressure extending from the western Atlantic
westward along 29N to the N central Gulf will sink southeast
through Tue. Moderate NE to E winds will pulse to fresh during the
late afternoon and evenings off the NW Yucatan peninsula through
early next week. Meanwhile, a weak frontal boundary is expected to
stall just north of the central and NE Gulf during the weekend.

CARIBBEAN SEA...

Satellite imagery shows scattered showers and isolated
thunderstorms near Hispaniola, Jamaica, and Cuba due to the
influences of upper-level troughing and a tropical wave in the
area. That tropical wave is also producing convection near the
coasts of Colombia and NW Venezuela, described above in the
tropical waves section. A recent ASCAT satellite wind data pass
shows fresh trade winds in the south-central Caribbean, south of
15N between 67W-71W, where seas are likely 4-6 ft. A 12/2230 UTC
satellite altimeter pass indeed measured significant wave heights
of 4 to 5 ft in between eastern Hispaniola and the Gulf of
Venezuela. Moderate trades prevail elsewhere east of 76W with 4-5
ft seas. Gentle to moderate winds prevail west of 76W with 2-5 ft
seas.

The Atlantic high pressure ridge extends along 29-30N and will
drift southward and weaken through early next week. Moderate to
fresh trade winds over the central Caribbean will weaken to
moderate today through Mon, then increase to fresh late Mon
through Tue night. A broad surface trough that accompanies a
tropical wave along 51W is expected to reach the Lesser Antilles
tonight, move across the eastern Caribbean early Sun through early
Mon, then across the central Caribbean Mon through late Wed.

ATLANTIC OCEAN...

Refer to the section above for details on the tropical waves
moving across the basin.

A surface ridge axis extends from 1025 mb high pressure near
31N42W to 31N65W to 29N77W to 1017 mb high pressure in the NE
Gulf near 28N85W. Recent ASCAT satellite wind data shows gentle
anticyclonic winds along and within 300 nm S of the ridge axis,
including over the NW Bahamas. Seas are likely near 3 ft in this
area, west of 60W. Mid- to upper-level troughing is occurring
over most of the area where the surface ridge is. As a result,
scattered moderate convection is noted from 26N-31N between 43W-
55W. A line of showers and thunderstorms about 75 nm wide extends
from 29.5N73.5W east-northeastward to beyond 31N71.5W. A third
cluster of numerous moderate isolated strong convection is noted
off the coast of NE Florida from 28.5N-31N between 78W and the
coast of NE Florida. Isolated showers and tstorms are also noted
just N of the NW Bahamas. Moderate trades prevail south of 23N
to the north of Hispaniola and over the southeastern Bahamas,
where seas are 3-5 ft.

The broad 1008 mb low along the monsoon trough near 14N20W is
accompanied by moderate winds. However, ASCAT satellite wind data
shows fresh to locally strong SW winds to the south from
05N-11.5N between 15W-23W. Fresh NE winds are occurring to the
north, covering the area between the Cabo Verde Islands and the
Canary Islands. Altimeters passing over the area have measured
seas of 7 to 8 during the past 6 to 12 hours, from 15N-22N between
30W and the coast of Africa. Moderate to fresh trades and 5-7 ft
seas prevail from 14N-24N between 30W-60W.

An earlier outflow boundary, analyzed along 43W at 12/1800 UTC,
was still producing 30 kt winds according to ASCAT data from
around 13/0000 UTC over a small area from 13N-14.5N between
44.5W-46W.

For the forecast W of 55W, the ridge that extends from 31N55W to
31N65W to 29N81W will weaken and sink southward through early
next week as a frontal boundary moves off the eastern seaboard and
stalls from NE Florida east-northeastward to north of 31N78W.
Moderate E winds S of 23N will veer to the SE and weaken to
gentle later this morning, then change little into next week.
Light to gentle variable winds are expected elsewhere through the
period. A tropical wave will reach the southeast forecast waters
between 55W-65W later this morning, bringing a slight increase in
winds and seas over those waters through early Mon. A cold front
may move over the waters northeast of NE Florida late Tue, then
stall and weaken through Wed night.

$$
Hagen
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