[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 271202
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
805 AM EDT Wed Sep 27 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
1145 UTC.

...SPECIAL FEATURES...

Tropical Storm Maria is centered near 35.4N 72.8W at 27/1200 UTC
or about 135 nm east of Cape Hatteras North Carolina, moving
north at 5 kt. Minimum central pressure is 978 mb. Maximum
sustained winds are 60 kt with gusts to 75 kt. Maria is a very
large cyclone with tropical storm-force winds extending outward
up to 200 nm from the center. Scattered moderate convection is
within 300 nm of the storm in the eastern semicircle. Stable air
on the western semicircle is resulting in mainly showers within
300 nm west of the center. See the latest NHC Forecast/Advisory
under AWIPS/WMO headers MIATCMAT5/WTNT25 KNHC for more details.

Hurricane Lee is centered near 30.2N 56.3W at 27/0900 UTC or
about 451 nm ESE of Bermuda. Lee is moving WNW at 8 kt. Estimated
minimum central pressure is 971 mb. Maximum sustained winds are
95 kt with gusts to 115 kt. Lee is a small cyclone with numerous
moderate and isolated strong convection confined to within 90 nm
of the center. Lee is forecast to remain a hurricane the next
couple of days as it turns toward the northeast on Thursday. See
the latest NHC Forecast/Advisory under AWIPS/WMO headers
MIATCMAT4/WTNT24 KNHC for more details.

...TROPICAL WAVES...

A tropical wave is off the coast of Africa with axis extending
along 19W from 04N-16N, moving west at 15 kt. SSMI TPW imagery
shows a very moist area. Surface and 700 mb trough are also
present. Scattered moderate isolated strong convection is E of
the wave axis from 08N-11N between 15W-18W.

A tropical wave extends along 45W/47W from 06N-18N, moving west
at 15 kt. This wave is well defined in 700 mb wind fields. A
fairly dry and stable environment covers the northern portion of
the wave. Scattered showers are south of 13N between 42W-50W.

A tropical wave is in the central Caribbean along 74W, from 10N-
20N, moving west at 10-15 kt. The wave is embedded within a moist
area ,and a weak 700 mb trough. Isolated moderate convection is
within 90 nm of the wave axis.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends from the coast of Africa near 12N16W
to 13N19W to 10N26W to 11N34W to 09N40W. The Intertropical
Convergence Zone extends from 09N40W to 10N46W. The ITCZ resumes
W of a tropical wave near 10N48W to 08N59W. Aside from
convection associated with the tropical waves, scattered
moderate to isolated strong convection is from 08N-14N between
52W-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. In the upper levels, a large upper level trough is
over the western half of the U.S. with axis along 113W. 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 28N83W 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 Yucatan Channel,
Yucatan Peninsula, and the Bay of Campeche.

CARIBBEAN SEA...

A surface trough is over the W Caribbean from 21N88W to 15N88W.
Scattered moderate to isolated strong convection is over the NW
Caribbean, Cayman Islands, and Jamaica, from 15N-22N between 78W-
84W. Much of this convection is also enhanced by upper level
diffluence. A tropical wave is over the central Caribbean.
Elsewhere, scattered showers are over the Leeward and Windward
Islands, while Puerto Rico has fair weather. 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 from 11N-16N between 75W-87W. Expect over
the next 24 hours for continued showers and convection over the
W Caribbean and Central America W of 75W.

...HISPANIOLA...

Pesently fair weather is over Hispaniola. Upper level conditions
will support additional afternoon and evening showers and
thunderstorms on Wednesday.

ATLANTIC OCEAN...

Two tropical waves are moving across the basin. Please refer to
the tropical waves section above for details. Tropical Storm
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 eastern 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
from 22N-28N, west of 71W. Elsewhere, surface ridging prevails
across much of the remainder of the central and the eastern
Atlantic, anchored by a 1021 mb high centered near 33N41W.

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

$$
Formosa
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