[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 102357
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU SEP 10 2015

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
2315 UTC.

...SPECIAL FEATURES...

TROPICAL STORM HENRI IS CENTERED NEAR 33.9N 60.7W AT 10/2100 UTC
OR 225 NM E-NE OF BERMUDA AND ABOUT 840 NM S-SW OF CAPE RACE
NEWFOUNDLAND MOVING N AT 13 KT. ESTIMATED MINIMUM CENTRAL
PRESSURE IS 1008 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH
GUSTS TO 45 KT. TROPICAL STORM HENRI REMAINS POORLY ORGANIZED
WITH SOME VERTICAL SHEAR THAT IS FORECASTED TO RELAX OVERNIGHT.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 60 NM OF
LINE FROM 33N57W TO 36N60W. PLEASE SEE LATEST NHC FORECAST/
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE
DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE IN THE W TROPICAL ATLC EXTENDS FROM 18N32W TO
8N35W MOVING W-SW 15-20 KT OVER PAST 24 HOURS. SSMI TPW
INDICATES THE WAVE IS WITHIN A HIGH AMPLITUDE VERY BROAD SURGE
OF DEEP MOISTURE. THERE IS NO ASSOCIATED DEEP CONVECTION WITH
SCATTERED SHOWERS FROM 12N-15N BETWEEN 33W-38W.

TROPICAL WAVE...REMNANTS OF GRACE...EXTENDS FROM 19N57W TO
12N59W MOVING W NEAR 20 KT OVER PAST 24 HOURS. SSMI TPW
INDICATES THE WAVE IS WITHIN A HIGH AMPLITUDE SURGE OF DEEP
MOISTURE. SCATTERED MODERATE/ISOLATED STRONG CONVECTION WITHIN
75 NM OF LINE FROM 15N56W TO 18N60W. SCATTERED SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS ARE OVER THE LESSER ANTILLES S
OF GUADELOUPE FROM 58W-64W.

TROPICAL WAVE IN THE CENTRAL CARIBBEAN IS ALONG 71W FROM 16N TO
OVER SOUTH AMERICA MOVING W NEAR 25 KT OVER THE PAST 24 HOURS.
SSMI TPW INDICATES THE WAVE IS EMBEDDED WITHIN A LOW AMPLITUDE
SURGE OF DEEP MOISTURE. THERE IS NO ASSOCIATED DEEP CONVECTION
WITH SCATTERED SHOWERS FROM 12N-15N BETWEEN 66W-70W.

TROPICAL WAVE IN THE W CARIBBEAN IS ALONG 84W/85W FROM 17N TO
OVER CENTRAL AMERICA MOVING W NEAR 25 KT OVER THE PAST 24 HOURS.
SSMI TPW INDICATES THE WAVE IS EMBEDDED WITHIN A LOW AMPLITUDE
SURGE OF MODERATE MOISTURE. THERE IS NO ASSOCIATED DEEP
CONVECTION IN THE CARIBBEAN WATERS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH AXIS EXTENDS FROM OVER AFRICA INTO THE E
TROPICAL ATLC NEAR 12N16W ALONG 10N20W 12N26W TO E OF A TROPICAL
WAVE NEAR 11N34W. THE ITCZ BEGINS W OF THE TROPICAL WAVE NEAR
10N37W ALONG 9N46W TO 14N56W. SCATTERED MODERATE TO STRONG
CONVECTION IS INLAND AND WITHIN 45/60 NM ALONG THE COAST OF
AFRICA FROM 10N-12N. CLUSTERS OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION ARE FROM 6N-10N BETWEEN 15W-29W...FROM 6N-11N
BETWEEN 37W-46W...AND WITHIN 90/120 NM S OF THE ITCZ BETWEEN 50W-
56W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER TROUGH DIPS S OVER THE N GULF SUPPORTING FRONTAL
BOUNDARY THAT IS WELL INLAND OVER THE SE CONUS. SHOWERS/
THUNDERSTORMS ASSOCIATED WITH THIS FRONT ARE MOSTLY INLAND OVER
GEORGIA TO TEXAS WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORM OVER THE GULF WATERS N OF 28N W OF 85W. AN UPPER
RIDGE OVER W MEXICO IS PROVIDING DIFFLUENCE ALOFT TO GENERATE
SCATTERED TO NUMEROUS SHOWERS/ISOLATED THUNDERSTORMS N OF 24N W
OF 92W. A SECOND UPPER RIDGE EXTENDS FROM THE NW CARIBBEAN INTO
THE W ATLC PROVIDING DIFFLUENCE ALOFT TO GENERATE ISOLATED
SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM 24N-26N E OF
84W TO OVER S FLORIDA AND THE FLORIDA KEYS. A WEAK SURFACE RIDGE
EXTENDS FROM THE W ATLC ACROSS CENTRAL FLORIDA TO OVER THE GULF
WITH A 1016 MB HIGH NEAR 27N86W. THE ABOVE COLD FRONT WILL MOVE
INTO THE N/CENTRAL GULF FRI NIGHT WITH A SECOND FRONT ENTERING
THE AREA SAT NIGHT.

CARIBBEAN SEA...
AN UPPER RIDGE COVERS THE CARIBBEAN W OF 75W AND IS ANCHORED
NEAR 18N85W EXTENDING A RIDGE AXIS ACROSS CENTRAL CUBA INTO THE
W ATLC. A SECOND WEAKER UPPER RIDGE IS ANCHORED IN THE W
TROPICAL ATLC COVERING THE E CARIBBEAN E OF 68W. A WEAK INVERTED
SURFACE TROUGH IS BETWEEN THESE UPPER RIDGES EXTENDING FROM THE
GUAJIRA PENINSULA OF COLOMBIA TO THE MONA PASSAGE. CLUSTERS OF
AFTERNOON SHOWERS/THUNDERSTORMS HAVE DEVELOPED INLAND OVER
PUERTO RICO...HISPANIOLA...CUBA...AND JAMAICA. THE MONSOON
TROUGH EXTENDS FROM COLOMBIA NEAR 11N75W ALONG 10N80W ACROSS W
PANAMA/COSTA RICA NEAR 9N83W WITH SCATTERED TO NUMEROUS
SHOWERS/ISOLATED THUNDERSTORMS S OF LINE FROM NICARAGUA NEAR
13N84W TO PANAMA NEAR 9N78W. W CARIBBEAN TROPICAL WAVE WILL MOVE
W OF THE AREA FRI. CENTRAL CARIBBEAN TROPICAL WAVE WILL MOVE
INTO THE W CARIBBEAN FRI NIGHT THROUGH SAT. THE W TROPICAL ATLC
TROPICAL WAVE...REMNANTS OF GRACE...WILL ENTER THE E CARIBBEAN
TONIGHT AND INTO THE CENTRAL ATLC FRI NIGHT REACHING THE W
CARIBBEAN SAT NIGHT.

...HISPANIOLA...
AFTERNOON SHOWERS/THUNDERSTORMS HAVE DEVELOPED OVER THE
DOMINICAN REPUBLIC AND ARE MOVING INTO HAITI. DAYTIME HEATING
COUPLED WITH OROGRAPHIC LIFTING COULD PRODUCE ISOLATED SHOWERS
IN THE AFTERNOON/EVENING HOURS THROUGH FRI. MOISTURE AND
POSSIBLE SHOWERS/THUNDERSTORMS ASSOCIATED WITH THE TROPICAL
WAVE...REMNANTS OF GRACE...IS CURRENTLY E OF THE LESSER ANTILLES
AND WILL APPROACH THE ISLAND FRI NIGHT SPREADING OVER THE
ISLAND SAT.

ATLANTIC OCEAN...
AN UPPER RIDGE OVER THE NW CARIBBEAN EXTENDS ACROSS CENTRAL CUBA
AND INTO THE W ATLC ALONG 23N79W TO BEYOND 32N75W. A WEAK
SURFACE RIDGE COVERS THE W ATLC WITH A 1017 MB HIGH NEAR 26N74W
THEN EXTENDS A RIDGE AXIS W OVER CENTRAL FLORIDA INTO THE GULF
OF MEXICO. AN UPPER TROUGH IS TO THE E OF THE ABOVE FEATURES
EXTENDING ACROSS BERMUDA TO THE MONA PASSAGE AND IS GENERATING
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 23N-27N BETWEEN
61W-71W. AN UPPER LOW IS IN THE CENTRAL ATLC NEAR 28N45W
GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS
WITHIN 300 NM OF LINE FROM 26N51W TO BEYOND 32N55W. A SURFACE
RIDGE COVERS THE REMAINDER OF THE ATLC E OF 55W ANCHORED BY A
1023 MB HIGH N OF THE DISCUSSION AREA. A WEAK SURFACE TROUGH
DIVIDES THE ABOVE SURFACE RIDGE EXTENDING FROM 32N28W 31N32W
THROUGH A WEAK 1017 MB LOW NEAR 28N35W ALONG 27N38W TO 27N46W. S
OF THE SURFACE TROUGH IS A 1019 MB HIGH IN THE E ATLC NEAR
29N26W AND A 1018 MB HIGH IN THE CENTRAL ATLC NEAR 25N45W. THE W
ATLC SURFACE RIDGE WILL SHIFT SLOWLY E TONIGHT THEN LOSE
IDENTITY EARLY FRI ALONG A RIDGE BUILDING W NEAR 27N AND SHIFT
TO THE E OF THE BAHAMAS ON SAT NIGHT.

FOR ADDITIONAL INFORMATION PLEASE
VISIT HTTP://WWW.HURRICANES.GOV/MARINE

$$
PAW
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