[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 241751
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
151 PM EDT Mon Aug 24 2020

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 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1200 UTC surface analysis and satellite imagery through
1715 UTC.

...SPECIAL FEATURES...

Tropical Storm Laura is centered near 21.2N 80.6W or about 56 nm
east-southeast of Cayo Largo, Cuba and 126 nm east of the
Isle of Youth moving WNW, or 285 degrees, 17 kt. The
estimated minimum central pressure is 1002 mb. The maximum
sustained wind speeds are 50 kt with gusts to 60 kt. Laura has
acquired a well pronounced banding feature to the south of the
center. Scattered moderate to strong convection is from
16N-23N between 76W-84W. Some decrease in forward speed is
expected over the next day or so. A turn toward the northwest
is forecast by Wednesday, and a northwestward to
north-northwestward motion should continued through Wednesday
night. On the forecast track, the center of Laura will move
over the Caribbean Sea just offshore of the southern coast of
Cuba this afternoon, cross western Cuba this evening, and move
into the southeastern Gulf of Mexico overnight. Laura is then
forecast to move over the central and northwestern Gulf of
Mexico Tuesday night and Wednesday, and approach the
northwestern coast of the Gulf of Mexico Wednesday night.
Please read the latest NHC Public Advisory at
https://www.nhc.noaa.gov/text/MIATCPAT3.shtml and Forecast/
Advisory at https://www.nhc.noaa.gov/text/MIATCMAT3.shtml, for
more details.

Tropical Storm Marco is centered near 28.5N 88.5W or about 48 nm
southeast of the mouth of the Mississippi River moving north-
northwest or 330 degrees at 7 kt. The estimated minimum pressure
is 1006 mb, The maximum sustained wind speeds are 45 kt with
gusts to 55 kt. Satellite imagery shows that Marco is undergoing
southwesterly vertical shear and as a result is on a weakening
trend as its center is entirely exposed within 50 nm
to the southwest of a large area of scattered moderate to strong
convection from 28N-32N between 84W-88W to include the Florida
panhandle. A turn to the west-northwest is expected to occur by
Tuesday, and this motion should continue until the system
dissipates in a couple of days. Marco is expected to produce
total rainfall accumulations of 3 to 6 inches with isolated
maximum amounts of 10 inches across portions of the northeast
and north-central Gulf coast through Tuesday. This rainfall may
result in areas of flash, urban and small stream flooding along
the same area. Please read the latest NHC Public Advisory at
https://www.nhc.noaa.gov/text/MIATCPAT4.shtml and
Forecast/Advisory at
https://www.nhc.noaa.gov/text/MIATCMAT4.shtml, for more details.

..TROPICAL WAVES...

A far eastern Atlantic tropical wave has its axis along 20W
from 02N to 20N, moving westward at 10 to 15 kt. Scattered
moderate convection is from 04N-10N between 13W-28W. Scattered
showers are elsewhere within 90 nm of the wave axis.

A Central Atlantic tropical wave has its axis along 41W from
02N to 18N. It is moving westward at 10-15 kt. This wave
is moving through a stable and dry surrounding environment.
Only isolated weak showers are noted within 90 nm of wave
axis.

A trough extends from near 25N55W to 11N60W. Scattered
showers are within 180 nm west of the trough.

A central Caribbean tropical wave has its axis along 81W
south of 15N, moving westward at 10-15 kt. Scattered moderate
convection is S of 11N.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis passes through the northernmost coastal
sections of Mauritania southwestward to 15N25W to 10N29N and
west to 09N39W. The ITCZ axis extends from 09N43W to 08N52W to
11N58W. Besides the convection mentioned in the tropical wave
section, scattered showers are within 120 nm of the monsoon
trough and ITCZ.

GULF OF MEXICO...

Please see the Special Feature section above for further details
on Tropical Storm Marco and on Tropical Storm Laura soon to enter
the basin.

Other than Tropical Storm Marco, generally weak high pressure
is present over the area. ASCAT data shows gentle to moderate
winds over most of the Gulf, with the exception of the areas
surrounding Marco. Elsewhere, isolated moderate convection is
over the Straits of Florida E of 83W. Over the Bay of
Campeche, scattered moderate convection is from 18N-23N between
94W-97W.

Tropical Storm Marco is near 28.5N 88.5W 1006 mb at 11 AM EDT
moving NNW at 7 kt. Maximum sustained winds 45 kt gusts 55 kt.
Marco will move inland to 29.2N 89.3W this evening, weaken to a
remnant low near 30.0N 91.3W Tue morning, 30.5N 93.6W Tue
evening, 30.9N 95.9W Wed morning, and dissipate Wed evening.

Tropical Storm Laura is near 21.2N 80.6W 1002 mb at 11 AM EDT
moving WNW at 17 kt. Maximum sustained winds 50 kt gusts 60 kt.
Laura will move to 22.2N 82.9W this evening, 23.6N 86.0W Tue
morning, strengthen to a hurricane near 25.2N 88.8W Tue evening,
26.8N 91.1W Wed morning, 28.7N 92.8W Wed evening, and inland to
31.2N 93.3W Thu morning. Laura will weaken to a tropical
depression while moving inland near 36.0N 90.9W by early Fri.

CARIBBEAN SEA...

Please see the Special Feature section above for further details
on Tropical Storm Laura.

Outside convection associated with Tropical Storm Laura and
the tropical wave along 77W, an area of scattered isolated
thunderstorms is over the eastern Caribbean south of 15N and
east of 67W to the Windward Islands. Similar activity is over
the far northeast part of the Caribbean to the northern Leeward
Islands. Increasing activity, in the form of scattered showers
and
thunderstorms moving to the southwest are seen over the British
and U.S. Virgin Islands to over eastern Puerto Rico. This
activity is being enhanced by an upper-level low that is over the
Atlantic near 22N62W. It is moving toward the west.

Tropical Storm Laura near 21.2N 80.6W 1002 mb at 11 AM EDT
moving WNW at 17 kt. Maximum sustained winds 50 kt gusts 60 kt.
Laura will move to 22.2N 82.9W this evening, 23.6N 86.0W Tue
morning, strengthen to a hurricane near 25.2N 88.8W Tue evening,
26.8N 91.1W Wed morning, 28.7N 92.8W Wed evening, and inland to
31.2N 93.3W Thu morning. Laura will weaken to a tropical
depression while moving inland near 36.0N 90.9W by early Fri.

ATLANTIC OCEAN...

A 1021 mb high is centered over the W Atlantic near 32N70W.
A 1024 mb high is centered over the E Atlantic near 33N34W.

An upper-level low is near 22N62W moving westward. An upper
trough extends from the low south-southeastward to 15N61W and
to near 12N61W. Satellite imagery shows increasing scattered
showers and thunderstorms from eastern Puerto to the U.S.
and British Virgin northward to 23N and between 60W-67W.

The pressure gradient between the E Atlantic high and the
lower pressures over W Africa supports near gale force
winds over the Canary Islands.

$$
Formosa
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