Tropical Weather Discussion
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000
AXNT20 KNHC 230000
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
800 PM EDT Fri Sep 22 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 1800 UTC surface analysis and satellite imagery through
2216 UTC.

...SPECIAL FEATURES...

Hurricane Maria is centered near 23.8N 71.6W at 23/0000 UTC, or
about 256 nm E of the central Bahamas, or about 326 nm ESE of
Nassau, moving NNW at 8 kt. Minimum central pressure is 953 mb.
Maximum sustained wind speed is 110 kt with gusts to 135 kt.
Numerous moderate to strong convection is within 90 nm of the
center, except within 120 nm in the S quadrant. Scattered moderate
convection is elsewhere within 300 nm in the N quadrant, 210 nm
in the E quadrant, 150 nm in the S quadrant and 120 nm in the W
quadrant. Maria is forecast to only very slowly decrease in
intensity during the next couple of days while it begins to turn
more northward. Please see the latest NHC Public Advisory under
AWIPS/WMO headers MIATCPAT5/ WTNT35 KNHC and the complete NHC
Forecast/Advisory under AWIPS/WMO headers MIATCMAT5/WTNT25 KNHC
for the complete details.

Tropical Depression Lee is centered near 30.8N 48.9W at 22/2100
UTC, or about 817 nm E of Bermuda moving N at 6 kt. Estimated
minimum central pressure 1014 mb. Maximum sustained winds 30 kt
with gusts to 40 kt. Scattered moderate to strong convection is
within 60 nm in the NE semicircle and within 30 nm in the SW
semicircle of Lee. Additional scattered moderate convection is
located to the SE of Lee from 21N to 27N between 39W and 46W,
associated with a middle to upper level low. Lee has regenerated
over the central Atlantic and is forecast to gradually
strengthen, becoming a tropical storm tonight, while turning to
the NE and E over the next couple of days. Please see the latest
NHC Forecast/Advisory under AWIPS/WMO headers MIATCMAT4/WTNT24
KNHC for the complete details.

Post-Tropical Cyclone Jose is centered near 39.3N 69.1W at
22/2100 UTC, or about 122 nm SSE of Nantucket, Massachusetts,
stationary. Estimated minimum central pressure is 996 mb. Maximum
sustained winds are 40 kt with gusts to 50 kt. No deep convection
is present with Jose. Tropical storm conditions have diminished at
coastal locations, and thus the final advisory has been issued.
Please see the final NHC Forecast/Advisory under AWIPS/WMO
headers MIATCMAT2/WTNT22 KNHC for the complete details.

...TROPICAL WAVES...

A tropical wave is off the coast of Africa with axis extending
from 17N17W to 01N19W, moving W at 5 to 10 kt. Abundant moisture
is present with the tropical wave axis as measured by SSMI TPW
imagery. Isolated moderate convection is from 06N to 11N between
15W and 21W.

A tropical wave is in the central Atlantic with axis extending
from 19N49W to just offshore of the coast of French Guiana near
06N52W, moving W at 10 kt. Plentiful moisture is present near the
tropical wave axis as indicated by SSMI TPW imagery. Widely
scattered moderate convection is from 14N to 19N between 49W and
53W, with additional isolated activity within 510 nm E of the
tropical wave axis.

...ITCZ/MONSOON TROUGH...

The monsoon trough axis extends from the African coast near
14N16W to 06N26W to 05N32W. The intertropical convergence zone
axis extends from 05N32W to 06N49W. Besides the convection
mentioned in the tropical waves section, scattered moderate
convection is from 06N to 08N between 33W and 35W.

...DISCUSSION...

GULF OF MEXICO...

High pressure located over western Tennessee extends a ridge axis
to the SW to across coastal sections of Texas. This ridge axis is
maintaining gentle to moderate E to SE flow with mainly 1 to 3 ft
seas across the Gulf of Mexico. Isolated convection is present
with a middle to upper level trough extending from an upper low
over upstate South Carolina to the NE Gulf near 30N85W to the SW
Gulf near 22N94W. Additional convection is firing over the Florida
Peninsula with the assistance of daytime heating, however the
activity is diminishing with the arrival of sunset.

CARIBBEAN SEA...

A surface trough trails Hurricane Maria which is moving NNW away
from the N coast of Hispaniola extending from southern Haiti near
18N73W to 13N78W. Associated outer rainbands with Maria continue
to induce flash flooding over Puerto Rico although this activity
should gradually diminish during the next couple of days as Maria
continues to move away from the area. The remainder of the
Caribbean is fairly tranquil with gentle to moderate winds W of
the surface trough axis, and moderate to fresh easterly flow in
the E Caribbean E of the trough axis. Aloft, a middle to upper
level trough extends across the NW Caribbean with mainly dry and
stable air, while upper anticyclonic flow prevails elsewhere.

...HISPANIOLA...

Outer rainbands associated with Hurricane Maria, which continues
to move NNW away from the N coast of the island, continue to
support heavy rainfall and localized flash flooding. Activity
should gradually diminish during the next couple of days as Maria
continues away from the area.

ATLANTIC OCEAN...

Please refer to Special Features section for more information on
Hurricane Maria and Tropical Depression Lee.

Otherwise, a surface trough is over the NW portion of the SW N
Atlantic basin reaching from near 31N76W to between Grand Bahama
and the E coast of Florida. This trough is supporting scattered
thunderstorms from the western Bahamas to the Florida Peninsula.
Upper level anticyclonic flow dominates the basin, except between
46W and 56W where a mainly N to S middle to upper level trough is
present.

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

$$
Lewitsky




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