[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 251200
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
805 AM EDT THU AUG 25 2016

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
1115 UTC.

...SPECIAL FEATURES...

Hurricane Gaston is centered near 19.5N 43.3W at 25/0900 UTC or
about 1065 nm east of the Leeward Islands moving northwest at 15
kt. Estimated minimum central pressure is 988 mb. Maximum
sustained wind speed is 65 kt with gusts to 80 kt. Scattered
moderate to isolated strong convection is from 18N-24N between
39W-45W. Please see the latest NHC Intermediate Public Advisory
under AWIPS/WMO headers MIATCPAT2/WTNT32 KNHC and the full
Forecast/Advisory under the AWIPS/WMO headers MIATCPAT2/WTNT22
KNHC for more details.

...Gale Warning for Southwest Atlantic...
A Gale warning has been issued for the area northeast of a broad
area of low pressure analyzed as a 1008 mb low north of
Hispaniola near 21N68.5W. These winds are expected to continue
for the next 24 hours. Scattered moderate to isolated strong
convection is from 17N-21N between 66W-69W including portions of
Puerto Rico and the Mona Passage, and from 17N to over
Hispaniola between 69W-73W. Environmental conditions have the
potential to become more conducive for tropical development over
the weekend when the system is near the central or northwestern
Bahamas. Regardless of development, gusty winds, heavy rains,
and possible flash floods and mudslides are likely to occur over
portions of Puerto Rico, the Turks and Caicos, Hispaniola, and
the southeastern and central Bahamas during the next couple of
days. There is a medium chance of tropical development in the
next 48 hours.

...TROPICAL WAVES...

None.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends across Africa into the east Tropical
Atlantic near 18N16W then continues along 11N23W 7N31W to 8N37W.
The ITCZ is not currently evident. The monsoon trough/ITCZ
continues to be disrupted by Hurricane Gaston. Clusters of
scattered moderate convection are within 60/75 nm of a line from
6N33W 5N25W 7N16W to inland over west Africa near 7N12W.

...DISCUSSION...

GULF OF MEXICO...

A broad upper ridge is anchored over north Mississippi covering
the Gulf waters north of 24N. An elongated upper trough extends
from the Yucatan peninsula near 20N91W to over Mexico just north
of Tampico. The diurnal surface trough is in the east Bay of
Campeche from 21N91W over Mexico to near 18N94W generating
isolated showers and thunderstorms in the east Bay of Campeche
south of 20N east of 95W. Clusters of scattered showers and
isolated thunderstorms dot the east Gulf north of 21N east of
905 to the Florida peninsula and over the flo9rida Keys. A weak
surface ridge extends from the northwest Atlantic across the
southeast CONUS to over the north Gulf and is anchored by a 1024
mb high in the northwest Atlantic and a 1023 mb high over North
Carolina. This surface ridge will persist through Saturday. The
low in the Special Features could cause winds and seas to
increase over the eastern Gulf late in the weekend to early next
week.

CARIBBEAN SEA...

The primary concern this morning is the low in the Special
Features moving just north of the Greater Antilles. Please see
the Special Features section above for the activity associated
with this system over the north/central Caribbean. The elongated
upper trough over the Gulf of Mexico extends across the Yucatan
along 20N to 80W. Clusters of scattered showers and isolated
thunderstorms are north of 20N to the coast of Cuba west of 80W
including the Yucatan Channel, within 120 nm along the coast of
Honduras between 84W-87W, and in the southwest Caribbean south
of 10N between Colombia and Costa Rica. Isolated showers and
possible isolated thunderstorms dot the remainder of the east
Caribbean north of 13N east of 68W to over the Lesser Antilles
and north of 16N between 71W-76W associated with the low in the
Special Features. The low in the Special Features will continue
to track northwestward. The strongest winds are found northeast
of the low.

...HISPANIOLA...

Currently scattered showers and isolated thunderstorms are over
portions of the island due to the low in the Special Features.
Please see the Special Features section above. The low is
expected to move northwestward north of the island through
today, but could still produce gusty winds, heavy rains, and
possible flash floods and mud slides over portions of the island
during the next couple of days.

ATLANTIC OCEAN...

The primary concern this morning is the low in the Special
Features moving just north of the Greater Antilles. Please see
the Special Features section above for the activity associated
with this system over the southwest Atlantic. The upper ridge
over the Gulf of Mexico extends a ridge axis across south
Georgia into the west Atlantic to near 28N75W. An upper trough
north of 30N is supporting a stationary front that extends
through 32N67W to 27N73W continuing as a surface trough across
the Bahamas to the north coast of Cuba near 23N80W. Scattered
showers and isolated thunderstorms are within 60 nm of a line
from 32N70W 28N76W to over Floria near 27N80W. The remnants of
Fiona is now a surface trough that extends from 30N68W to 27N69W
and coupled with diffluent flow from a second upper ridge to the
east of the above front is generating scattered showers and
possible isolated thunderstorms north of 27N between 59W-70W. An
upper low is over the central Atlantic near 25N52W and is
supporting a surface trough that extends from 31N49W to 25N53W.
Scattered showers and isolated thunderstorms are within 90 nm
either side of the surface trough. The upper trough is also
generating scattered showers/isolated thunderstorms west of
Hurricane Gaston within 75/90 nm of line from 25N46W to 26N48W.
The remainder of the east Atlantic north of Hurricane Gaston
east of 60W is dominated by a surface ridge anchored by a 1026
mb high southwest of the Azores near 36N32W and a 1024 mb high
near 35N45W. The Special Features low will track northwestward
through the Bahamas into the weekend with gale force winds
northeast of the surface low.

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

$$
PAW/NAR
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