[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 281033
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
633 AM EDT Thu Sep 28 2017

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 0600 UTC surface analysis and satellite imagery through
1015 UTC.

...SPECIAL FEATURES...

Tropical Storm Maria is centered near 36.8N 71.0W at 28/0900 UTC
or about 238 nm east-northeast of Cape Hatteras North Carolina,
moving ENE at 7 kt. Minimum central pressure is 982 mb. Maximum
sustained winds are 60 kt with gusts to 75 kt. Maria is a large
tropical cyclone with tropical storm force winds extending up to
200 nm from the center. Scattered moderate convection is within
270 nm of the storm in the northeastern semicircle. Stable air on
the southwestern semicircle is resulting in mainly showers within
300 nm southwest of the center. See the latest NHC Forecast/
Advisory under AWIPS/WMO headers MIATCMAT5/WTNT25 KNHC for more
details.

Hurricane Lee is centered near 32.5N 57.2W at 28/0900 UTC or
about 386 nm E of Bermuda. Lee is moving N at 8 kt. Estimated
minimum central pressure is 966 mb. Maximum sustained winds are 95
kt with gusts to 115 kt. Lee is a small tropical cyclone with
numerous moderate convection within 120 nm of the center. Lee is
forecast to remain a hurricane through Friday evening as it
accelerates over open ocean. See the latest NHC Forecast/Advisory
under AWIPS/WMO headers MIATCMAT4/WTNT24 KNHC for more details.

...TROPICAL WAVES...

A tropical wave off the coast of Africa is along 25W from 16N to
05N, moving west at 15 kt. This wave is embedded in a very moist
environment, and a sharp 700 mb trough. Widely scattered moderate
convection is within 180 nm of either side of the wave axis.

A tropical wave is in the central Atlantic along 51W/53W from 16N
to 06N, moving west at 10 to 15 kt. This wave is evident in 700
mb wind fields and is generating isolated moderate convection
within 180 nm of either side of the wave axis.

A tropical wave in the western Caribbean along 87W from 20N to
09N, moving west at 10 kt. The wave is embedded within a moist
environment, and a 700 mb trough. Isolated moderate convection is
within 180 nm of either side of the wave axis.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends from the coast of Africa near 11N16W
to 06N25W to 07N36W. The Intertropical Convergence Zone extends
from 07N36W to 10N51W, then resumes west of a tropical wave near
10N54W to 10N61W. Aside from convection associated with the
tropical waves, widely scattered moderate convection is from 10N-
16N between 56W-62W.

...DISCUSSION...

GULF OF MEXICO...

Slight surface ridging is over the N Gulf of Mexico, with mostly
5-15 kt E flow over the Gulf. Strongest winds are over the W
Gulf W of 90W. A surface trough is over the Bay of Campeche from
22N92W to 16N93W. Scattered moderate to isolated strong
convection is within 120 nm of the trough. In the upper levels, a
large upper level trough is over the western half of the U.S.
with axis along 112W. Upper level diffluence E of the axis is
producing convection over S Texas and Mexico between 95W-105W. An
upper level low is centered over the NE Gulf of Mexico near 28N84W
with strong subsidence. Again upper level diffluence SE of the
center is producing showers and convection over W Cuba, the
Straits of Florida, and the Bahamas. Expect over the next 24 hours
for an increase of showers and convection over the SW Gulf.

CARIBBEAN SEA...

A tropical wave is over the western Caribbean. Elsewhere,
scattered showers are over the Windward Islands advecting from the
Atlantic. Lastly, the eastern extent of the E Pacific monsoon
trough is well into the SW Caribbean extending from SE Nicaragua
to N Colombia. Isolated moderate convection is over Panama, while
N Colombia has scattered moderate to strong convection. In the
upper levels, diffluence from the NE Gulf upper level low is
producing scattered moderate to isolated strong convection over
the central Caribbean from 15N-19N between 78W-82W. Expect over
the next 24 hours for more showers and convection to advect over
the E Caribbean.

...HISPANIOLA...

Presently fair weather is over Hispaniola. Expect afternoon and
evening showers and thunderstorms on Thursday.

ATLANTIC OCEAN...

Two tropical waves are moving across the basin. Please refer to
the tropical waves section above for details. Hurricane Maria in
the western Atlantic and Hurricane Lee in the central Atlantic are
discussed in the special features section above. A plume of
moisture is being pulled northeast across the Bahamas and
surrounding waters by an upper low over the NE Gulf of Mexico,
and by low level southerly flow well to the south of Maria. This
plume combined with upper level diffluence from the upper low
supports numerous showers and scattered thunderstorms W of 63W.
Elsewhere, surface ridging prevails across much of the remainder
of the central and the eastern Atlantic, anchored by a 1022 mb
high centered near 33N40W.

For additional information please visit
http://www.hurricanes.gov/marine

$$
Formosa
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