[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 280531
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
131 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 0000 UTC surface analysis and satellite imagery through
0515 UTC.

...SPECIAL FEATURES...

Hurricane Maria is centered near 36.8N 71.5W at 28/0300 UTC or
about 217 nm east-northeast of Cape Hatteras North Carolina,
moving northeast at 6 kt. Minimum central pressure is 979 mb.
Maximum sustained winds are 65 kt with gusts to 80 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 31.7N 57.3W at 28/0300 UTC or
about 382 nm E of Bermuda. Lee is moving NNW at 6 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 as it turns
northeast and 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 23W/24W 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 50W/51W 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 84W 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 11N15W
to 07N20W to 06N30W to 07N35W. The Intertropical Convergence Zone
extends from 07N35W to 09N48W, then resumes west of a tropical
wave near 10N53W to 10N61W. Aside from convection associated with
the tropical waves, widely scattered moderate convection is from
10N-16N between 54W-59W.

...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
21N90W to 17N93W. Scattered moderate to isolated strong convection
is within 90 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
Jamaica and the central Caribbean from 14N-19N between 75W-80W.
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 33N45W.

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

$$
Formosa
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