[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 301146
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...SPECIAL FEATURES...

HURRICANE OPHELIA IS CENTERED NEAR 22.9N 62.7W AT 30/1200 UTC OR
ABOUT 575 NM S OF BERMUDA MOVING N-NW AT 8 KT. ESTIMATED MINIMUM
CENTRAL PRESSURE IS 970 MB. MAXIMUM SUSTAINED WIND SPEED IS 90
KT WITH GUSTS TO 110 KT. PLEASE SEE LATEST NHC FORECAST/ADVISORY
UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS.
OPHELIA HAS RAPIDLY STRENGTHEN DURING THE PAST 12 HOURS BASED ON
AN EYE FEATURE OCCASIONALLY APPARENT ON SATELLITE IMAGERY.
SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 60/75 NM OF THE
CENTER IN ALL QUADRANTS. SCATTERED SHOWERS/ISOLATED TSTMS COVER
THE REMAINDER OF THE AREA FROM 21N-26N BETWEEN 60W-64W. CLUSTERS
OF SCATTERED SHOWERS/ISOLATED TSTMS ARE WITHIN 45 NM OF A LINE
FROM 18N59W ACROSS THE LEEWARD ISLANDS NEAR GUADELOUPE INTO THE
E CARIBBEAN ALONG 15N64W TO NEAR 16N67W.

TROPICAL STORM PHILIPPE IS CENTERED NEAR 21.9N 44.9W AT 30/0900
UTC OR ABOUT 1000 NM E-NE OF THE LEEWARD 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 THE POTENTIAL FOR
FURTHER STRENGTHENING. SCATTERED MODERATE/STRONG CONVECTION IS
WITHIN 60/75 NM OF THE CENTER IN ALL QUADRANTS AND WITHIN 60 NM
OF LINE FROM 22N40W TO 24N44W.

...TROPICAL WAVES...

TROPICAL WAVE IS ANALYZED ALONG 36W BETWEEN 3N-10N MOVING W
10-15 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 10N14W TO 9N28W. THE ITCZ AXIS HAS BEEN RE-ESTABLISHED
EXTENDING FROM 4N39W TO INLAND OVER SOUTH AMERICA NEAR 4N52W.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
WITHIN 90 NM ALONG THE COAST OF W AFRICA BETWEEN 8N-15N...FROM
4N-10N BETWEEN 19W-33W AND FROM 5N-13N BETWEEN 44W-49W.

...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 US CONUS. A SHORTWAVE UPPER TROUGH IS EMBEDDED WITHIN THIS
FLOW EXTENDING FROM NE GEORGIA TO A SMALL UPPER LOW MOVING OVER
THE FLORIDA PANHANDLE JUST E OF TALLAHASSEE. A SECOND UPPER
SHORTWAVE EXTENDS FROM OVER CENTRAL TEXAS INTO NE MEXICO
GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER S TEXAS
INTO THE FAR W GULF WATERS WITHIN 90 NM ALONG THE COAST FROM S
OF TUXPAN MEXICO TO JUST N OF CORPUS CHRISTI TEXAS. 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 1014 MB HIGH LOCATED NEAR 27N94W. CLUSTERS OF
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE INT HE BAY OF
CAMPECHE S OF 20N BETWEEN 91-96W. THE WEAK HIGH PRESSURE WILL
DISSIPATE TODAY AS A COLD FRONT MOVES INTO THE N GULF. THE FRONT
WILL DRIFT SE THROUGH THE YUCATAN CHANNEL AND BAY OF CAMPECHE
EARLY SAT. NORTHERLY WINDS WILL INCREASE IN WAKE OF FRONT THIS
WEEKEND THEN DIMINISH NEXT WEEK.

CARIBBEAN SEA...
THE PRIMARY CONCERN AGAIN THIS MORNING IS HURRICANE OPHELIA N OF
THE LEEWARD/VIRGIN ISLANDS AND THE LINGERING SHOWERS/
THUNDERSTORMS OVER THE LEEWARD 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/NICARAGUA BORDER GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS S OF 12N TO INLAND OVER COLOMBIA AND PANAMA.
CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS DOT THE W
CARIBBEAN MAINLY S OF 20N W OF 84W TO OVER THE YUCATAN PENINSULA
AND CENTRAL AMERICA AND WITHIN 120/150 NM OF LINE FROM NICARAGUA
NEAR 13N84W TO OVER S HAITI NEAR 19N74W. THIS IS LEAVING THE
REMAINDER OF THE E CARIBBEAN UNDER MOSTLY CLEAR SKIES AGAIN THIS
MORNING. A COLD FRONT WILL ENTER THE NW CARIBBEAN SAT MORNING
THEN GRADUALLY DISSIPATE FROM THE WINDWARD PASSAGE TO THE GULF
OF HONDURAS EARLY NEXT WEEK.

ATLANTIC OCEAN...
THE PRIMARY CONCERN THIS MORNING 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 SUPPORTING A SURFACE TROUGH EXTENDS AT 30/0900 UTC FROM
OFF THE GEORGIA COAST NEAR 31N80W TO ALONG THE FLORIDA PENINSULA
BETWEEN DAYTONA BEACH TO MIAMI INTO THE STRAITS OF FLORIDA NEAR
24N80W WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 29N W
OF 78W TO THE COAST OF US AND WITHIN 90 NM OF 71W N OF 27N TO
BEYOND 32N. 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 21N75W TO 28N71W PROVIDING DIFFLUENT ENVIRONMENT TO
GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 120 NM
OF LINE FROM 21N72W 25N76W TO 29N76W INCLUDING THE BAHAMA
ISLANDS...THE TURKS AND CAICOS ISLANDS. AN UPPER TROUGH EXTENDS
S INTO THE CENTRAL ATLC N OF 26N BETWEEN 25W-45W SUPPORTING A
COLD FRONT THAT EXTENDS INTO THE REGION NEAR 32N28W TO 31N32W
WHERE IT BECOMES STATIONARY TO 29N43W AND GENERATING SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS WITHIN 200 NM SE OF THE FRONT E
OF 37W. A WEAK 1019 MB HIGH IS LOCATED NEAR 27N30W. A WEAK FRONT
WILL MOVE OFF THE FLORIDA E COAST THEN DRIFT SE UNTIL A
RE-INFORCING COLD FRONT MOVES OFF THE GEORGIA COAST TONIGHT AND
MERGES WITH THE PREVIOUS FRONT ON SAT. THE COMBINED FRONT WILL
THEN EXTEND FROM BERMUDA TO THE WINDWARD PASSAGE LATE SUN
DRIFTING SE AND DISSIPATE THROUGH TUE.

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

$$
PAW




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