000 AXNT20 KNHC 060539 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT TUE SEP 05 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 0515 UTC. ...SPECIAL FEATURES... HURRICANE KATIA IS CENTERED NEAR 25.8N 64.4W AT 06/0300 UTC OR ABOUT 390 NM S OF BERMUDA MOVING NW AT 9 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 946 MB. MAXIMUM SUSTAINED WIND SPEED IS 115 KT WITH GUSTS TO 140 KT. PLEASE SEE THE LATEST INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADER MIATCPAT2/WTNT32 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADER MIATCMAT2/ WTNT22 KNHC FOR MORE DETAILS. SCATTERED MODERATE/STRONG CONVECTION IS FROM 23N-28N BETWEEN 61W-67W. LARGE SWELLS GENERATED BY HURRICANE KATIA ARE EXPECTED TO AFFECT MOST OF THE EAST COAST OF THE UNITED STATES...BERMUDA...THE GREATER ANTILLES...AND EAST FACING BEACHES OF THE BAHAMAS DURING THE NEXT FEW DAYS. THESE SWELLS ARE LIKELY TO CAUSE LIFE THREATENING SURF AND RIP CURRENT CONDITIONS. PLEASE CONSULT PRODUCTS ISSUED BY LOCAL NATIONAL WEATHER SERVICE OFFICES FOR MORE INFORMATION. A BROAD AREA OF LOW PRESSURE ASSOCIATED WITH 1009 MB LOW IS CENTERED SW OF THE CAPE VERDE ISLANDS NEAR 10N31W MOVING W 10-15 KT. THIS FEATURE IS EMBEDDED WITHIN AN BROAD AREA OF DEEP LAYER MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ STRONG CONVECTION IS NW OF THE CENTER FROM 10N-14N BETWEEN 32W-38W. ORGANIZATION OF THIS SYSTEM HAS CHANGED LITTLE DURING THE PAST SEVERAL HOURS. ENVIRONMENTAL CONDITIONS APPEAR FAVORABLE FOR A TROPICAL DEPRESSION TO FORM DURING THE NEXT DAY OR TWO. THIS SYSTEM HAS A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. ...TROPICAL WAVES... TROPICAL WAVE IS MOVING INTO THE W TROPICAL ATLC EXTENDING FROM 19N49W THROUGH A 1012 MB LOW NEAR 15N48W TO 12N47W MOVING W NEAR 15 KT. THE WAVE N OF 13N INCLUDING THE LOW IS EMBEDDED WITHIN AN AREA OF DEEP LAYER MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY WITH DRIER AIR COMPLETELY UNDERCUTTING THE WAVE. ISOLATED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 150 NM W OF THE WAVE N OF 13N. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH IS ANALYZED ACROSS AFRICA ENTERING THE E TROPICAL ATLC NEAR 16N16W ALONG 12N23W THROUGH THE 1009 MB LOW IN THE SPECIAL FEATURES NEAR 10N31W TO 9N44W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 9N-12N BETWEEN 15W-17W INCLUDING THE COAST OF GUINEA-BISSAU. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 4N-9N BETWEEN 10W-47W. ...DISCUSSION... GULF OF MEXICO... BROAD UPPER TROUGH COVERS THE MISSISSIPPI VALLEY AND IS FINALLY LIFTING THE REMNANTS OF LEE E-NE ACROSS CENTRAL ALABAMA. THIS UPPER TROUGH EXTENDS OVER THE W GULF N OF 23N W OF A COLD FRONT THAT AT 06/0300 UTC ENTERS THE GULF WATERS JUST W OF TALLAHASSEE FLORIDA ACROSS APALACHICOLA BAY ALONG 25N88W TO MEXICO BETWEEN TUXPAN AND VERACRUZ. A SURFACE TROUGH EXTENDS FROM THE GULF WATERS NEAR 24N87W TO OVER THE YUCATAN PENINSULA NEAR MERIDA TO 17N93W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE N OF 27N E OF THE FRONT TO JUST INLAND OVER THE FLORIDA PENINSULA WITH SCATTERED/HEAVY SHOWERS AND SCATTERED/NUMEROUS THUNDERSTORMS ASSOCIATED WITH THE SURFACE TROUGH S OF 23N TO INLAND OVER THE YUCATAN BETWEEN 87W-90W. ISOLATED CLUSTERS OF SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS DOT THE REMAINDER OF THE SW GULF S OF 23N W OF 90W. DRY AIR ALOFT AND CLEARING SKIES DOMINATE THE NW GULF TONIGHT. THE COLD FRONT WILL MOVE SE THROUGH CENTRAL GULF TONIGHT AND BECOME STATIONARY FROM FLORIDA BIG BEND AREA TO DEVELOPING LOW PRESSURE OVER THE E BAY OF CAMPECHE THROUGH WED. FRONT WILL THEN MOVE S AND DISSIPATE THU AND FRI WHILE THE LOW PRESSURE LINGERS IN BAY OF CAMPECHE. CARIBBEAN SEA... AN INVERTED UPPER TROUGH AXIS EXTENDS FROM AN UPPER LOW OVER HONDURAS TO W CUBA AND THE ISLE OF YOUTH ENHANCING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS INLAND AND IN THE GULF OF HONDURAS S OF 17N W OF 87W. DRY STABLE AIR ALOFT DOMINATES THE CARIBBEAN E OF 80W. HOWEVER...AFTERNOON HEATING HAS DEVELOPED SCATTERED THUNDERSTORMS INLAND OVER CUBA AND HAITI WHICH HAVE DRIFTED INTO THE IMMEDIATE COASTAL WATERS. THE SW UPPER FLOW OVER THE SW CARIBBEAN IS CONVERGING WITH LOW LEVEL EASTERLY FLOW TO GENERATE A BAND OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 45/60 NM OF LINE FROM 12N79W TO 16N83W. THIS IS LEAVING THE REMAINDER OF THE CARIBBEAN UNDER REMARKABLY CLEAR SKIES TONIGHT. TROPICAL WAVE WILL MOVE N OF PUERTO RICO WED NIGHT. THE BROAD LOW PRESSURE IN THE SPECIAL FEATURES WILL ENTER TROPICAL N ATLC LATE THU AND MOVE INTO NE CARIBBEAN LATE FRI AND SAT. ATLANTIC OCEAN... NW UPPER FLOW DOMINATES THE W ATLC W OF HURRICANE KATIA WITH MOSTLY DRY STABLE AIR. HOWEVER...SOME ISOLATED SHOWERS/ THUNDERSTORMS ARE POSSIBLE WITHIN 60 NM ALONG THE COAST OF FLORIDA AND OVER THE N BAHAMA ISLANDS. THE UPPER RIDGE ASSOCIATED WITH HURRICANE KATIA COVERS THE REMAINDER OF THE W ATLC WITH GOOD OUTFLOW IN ALL QUADRANTS. AN UPPER LOW IS OVER THE CENTRAL ATLC CENTERED NEAR 27N51W AND IS EMBEDDED WITHIN A MUCH LARGER UPPER TROUGH THAT COVERS THE REMAINDER OF THE CENTRAL AND INTO THE E ATLC AND S INTO THE TROPICS WITH THE AXIS EXTENDING FROM AN UPPER LOW NEAR 33N25W SW TO 16N44W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 18N-23N BETWEEN 47W-55W. A SURFACE RIDGE DOMINATES THE ATLC N OF 20N W OF 60W AND ANCHORED BY A 1027 MB HIGH BETWEEN THE AZORES AND PORTUGAL AND A 1026 MB HIGH NEAR 33N51W. HURRICANE KATIA WILL CONTINUE TO MOVE THROUGH THE W ATLC THROUGH WED MOVING THEN N OF THE AREA OVERNIGHT WED NIGHT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW