[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 300553
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT FRI SEP 30 2011

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
0445 UTC.

...SPECIAL FEATURES...

HURRICANE OPHELIA IS CENTERED NEAR 22.0N 62.5W AT 30/0600 UTC OR
ABOUT 635 NM S OF BERMUDA MOVING N-NW AT 8 KT. ESTIMATED MINIMUM
CENTRAL PRESSURE IS 976 MB. MAXIMUM SUSTAINED WIND SPEED IS 80
KT WITH GUSTS TO 100 KT. PLEASE SEE LATEST NHC FORECAST/
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE
DETAILS. OPHELIA HAS STRENGTHEN WITH AN APPARENT EYE FEATURE.
SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 90 NM OF THE
CENTER IN ALL QUADRANTS. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS COVER THE AREA FROM 20N-26N BETWEEN 57W-63W AND
WITHIN 45 NM OF LINE FROM 18N59W ACROSS THE LEEWARD ISLANDS NEAR
GUADELOUPE INTO THE E CARIBBEAN TO NEAR 15N65W.

TROPICAL STORM PHILIPPE IS CENTERED NEAR 21.2N 44.0W AT 30/0300
UTC OR ABOUT 1040 NM E-NE OF THE LEEWARD ISLANDS AND ABOUT 1180
NM W-NW OF THE CAPE VERDE ISLANDS MOVING NW AT 11 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1004 MB. MAXIMUM SUSTAINED WIND
SPEED IS 40 KT WITH GUSTS TO 50 KT. PLEASE SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC
FOR MORE DETAILS. PHILIPPE HAS A UNORGANIZED APPEARANCE ON
SATELLITE IMAGERY WITH SCATTERED MODERATE/STRONG CONVECTION
WITHIN 60/75 NM 23N BETWEEN 41W-44W. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS COVER THE REMAINDER OF THE AREA WITHIN 120 NM OF
LINE FROM 23N37W 22N44W TO 20N46W.

...TROPICAL WAVES...

TROPICAL WAVE IS ANALYZED 10N33W 5N35W TO 2N336W MOVING W NEAR
15 KT. WAVE CONTINUES TO BE DIFFICULT TO DISCERN ON SATELLITE
IMAGERY. THE UPPER LEVEL SATELLITE WINDS SHOW NO DISTINCT
CURVATURE AND THE LOCATION IS BASED ON PERSISTENCE. NO
ASSOCIATED SHOWERS/CONVECTION.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA ENTERING THE E TROPICAL
ATLC NEAR 18N16W TO 17N21W. SCATTERED MODERATE/STRONG CONVECTION
IS WITHIN 45 NM ALONG THE COAST OF W AFRICA BETWEEN 8N-10N.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
FROM 3N-7N BETWEEN 26W-32W AND FROM 10N-13N BETWEEN 43W-47W.

...DISCUSSION...

GULF OF MEXICO...
THE LARGE UPPER LOW REMAINS CENTERED OVER THE GREAT LAKES AREA
COVERING THE CONUS FROM THE CENTRAL PLAIN STATES INTO THE NW
ATLC EXTENDING A BROAD UPPER TROUGH INTO THE N GULF N OF 28N
SUPPORTING YET ANOTHER FRONTAL BOUNDARY THAT REMAINS INLAND OVER
THE CONUS. A SHORTWAVE UPPER TROUGH IS EMBEDDED WITHIN THIS FLOW
EXTENDING FROM CENTRAL GEORGIA TO A SMALL UPPER LOW JUST OFF THE
COAST OF PANAMA CITY FLORIDA. A SECOND UPPER SHORTWAVE AND SMALL
UPPER LOW IS OVER THE RIO GRANDE NEAR LAREDO TEXAS GENERATING
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER E TEXAS INTO THE
FAR W GULF WATERS WITHIN 45 NM ALONG THE COAST OF TEXAS. A
SURFACE TROUGH EXTENDS AT 30/0300 UTC FROM SE GEORGIA OVER
ORLANDO FLORIDA INTO THE GULF NEAR FORT MYERS TO 25N83W WITH
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 30
NM OF THE THIS TROUGH MAINLY S OF 27N. A BROAD UPPER RIDGE
COVERS THE REMAINDER OF THE GULF ANCHORED OVER THE E PACIFIC
REGION GIVING MOST OF THE GULF WATERS NEAR WESTERLY FLOW ALOFT
WITH A WEAK 1016 MB HIGH LOCATED OVER S TEXAS. WEAK HIGH
PRESSURE WILL DISSIPATE FRI MORNING. A COLD FRONT WILL MOVE INTO
THE N GULF FRI AFTERNOON REACHING FROM SW FLORIDA TO NE MEXICO
SAT MORNING THEN STALL FROM THE STRAITS OF FLORIDA TO THE
YUCATAN SUN MORNING. STRONG HIGH PRESSURE WILL BUILD SE BEHIND
THE FRONT ACROSS THE N CENTRAL GULF SUN THROUGH TUE.

CARIBBEAN SEA...
THE PRIMARY CONCERN AGAIN TONIGHT IS HURRICANE OPHELIA N OF THE
LEEWARD/VIRGIN ISLANDS...SEE SPECIAL FEATURE SECTION ABOVE. THE
UPPER RIDGE OVER THE S GULF OF MEXICO EXTENDS OVER MOST OF THE
CARIBBEAN WITH THE EXCEPTION OF THE NE CARIBBEAN WHICH IS UNDER
THE INFLUENCE OF THE UPPER RIDGE ASSOCIATED WITH HURRICANE
OPHELIA. THE MONSOON TROUGH EXTENDS FROM COLOMBIA NEAR 10N76W
INTO THE E PACIFIC REGION OVER COSTA RICA NEAR 10N84W GENERATING
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 12N TO INLAND OVER
COLOMBIA AND PANAMA. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
WITHIN 90/120 NM OF LINE FROM 14N78W TO OVER HAITI NEAR 20N72W.
THIS IS LEAVING THE REMAINDER OF THE CARIBBEAN UNDER MOSTLY
CLEAR SKIES AGAIN TONIGHT. A WEAK PRESSURE PATTERN WILL CONTINUE
OVER THE CARIBBEAN THROUGH SUN.

ATLANTIC OCEAN...
THE PRIMARY CONCERN TONIGHT IS HURRICANE OPHELIA N OF THE
LEEWARD/VIRGIN ISLANDS AND TROPICAL STORM PHILIPPE OVER THE
CENTRAL ATLC...SEE SPECIAL FEATURE SECTION ABOVE. THE BROAD
UPPER TROUGH OVER THE US CONUS EXTENDS OVER THE W ATLC N OF 28N
TO 70W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
WITHIN 90 NM OF LINE FROM 28N71W TO BEYOND 32N70W AND WITHIN 30
NM OF LINE FROM 30N79W TO 33N76W. AN UPPER RIDGE COVERS THE
REMAINDER OF THE W ATLC E OF HURRICANE OPHELIA WITH THE AXIS
EXTENDING FROM THE N COAST OF CUBA NEAR 22N76W TO 28N71W
PROVIDING DIFFLUENT ENVIRONMENT TO GENERATE SCATTERED SHOWERS
AND POSSIBLE ISOLATED THUNDERSTORMS OVER THE BAHAMA ISLANDS
INCLUDING THE TURKS AND CAICOS. AN UPPER TROUGH EXTENDS S INTO
THE CENTRAL ATLC N OF 26N BETWEEN 30W-45W SUPPORTING A COLD
FRONT THAT EXTENDS INTO THE REGION NEAR 32N31W TO 29N42W
GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 120
NM SE OF THE FRONT E OF 35W. A WEAK SURFACE RIDGE COVERS THE E
ATLC ANCHORED BY A 1020 MB HIGH NEAR 27N29W. A WEAK FRONT WILL
MOVE OFF THE NE FLORIDA COAST FRI MORNING WHERE IT WILL STALL. A
REINFORCING COLD FRONT WILL MOVE OFF THE COAST FRI NIGHT AND
MERGE WITH THE STALLED FRONT REACHING FROM BERMUDA TO E CUBA SAT
NIGHT WHERE IT WILL THEN STALL AND DISSIPATE BY MON. HIGH
PRESSURE WILL BUILD IN FROM THE NE LATE MON AND TUE.

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

$$
PAW





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