000 AXNT20 KNHC 070542 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT WED SEP 07 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 28.4N 67.5W AT 07/0600 UTC OR ABOUT 275 NM S-SW OF BERMUDA MOVING NW AT 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 963 MB. MAXIMUM SUSTAINED WIND SPEED IS 90 KT WITH GUSTS TO 110 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/ISOLATED STRONG CONVECTION COVERS THE AREA FROM 24N-30N BETWEEN 63W-69W. LARGE SWELLS GENERATED BY HURRICANE KATIA WILL CONTINUE 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. TROPICAL DEPRESSION FOURTEEN IS CENTERED NEAR 11.6N 38.1W AT 07/0300 UTC OR ABOUT 865 NM W-SW OF THE CAPE VERDE ISLANDS AND ABOUT 1375 NM E OF THE LESSER ANTILLES MOVING W AT 16 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1008 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. PLEASE SEE THE LATEST INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADER MIATCPAT4/WTNT34 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADER MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 300 NM OF THE CENTER IN THE NW QUADRANT. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 75 NM OF LINE FROM 9N41W TO 12N45W. THE 1008 MB SURFACE LOW IS CENTERED IN THE S GULF OF MEXICO NEAR 20N94W AT 07/0300 UTC AND REMAINS AT THE TAIL END OF A FRONTAL BOUNDARY THAT HAS BECOME QUASI-STATIONARY. THIS SYSTEM HAS CHANGED LITTLE IN ORGANIZATION OVER THE PAST FEW HOURS...BUT SOME GRADUAL DEVELOPMENT OF THIS SYSTEM IS POSSIBLE OVER THE NEXT COUPLE OF DAYS. THIS SYSTEM HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE AS IT MOVES LITTLE DURING THE NEXT 48 HOURS. AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT IS SCHEDULED TO INVESTIGATE THIS SYSTEM TODAY...IF NECESSARY. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE S OF 22N TO INLAND OVER S MEXICO BETWEEN 91W-96W. ...TROPICAL WAVES... TROPICAL WAVE IN THE E TROPICAL ATLC IS ALONG 20W S OF 13N MOVING W 10-15 KT. WAVE IS EMBEDDED WITHIN AN AREA OF DEEP LAYER MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS W OF THE WAVE AXIS WITHIN 45/60 NM OF LINE FROM 12N23W TO 8N22W AND WITHIN 120 NM E OF THE WAVE FROM 11N-13N. TROPICAL WAVE IN THE W TROPICAL ATLC IS ALONG 55W/56W S OF 19N MOVING W NEAR 15 KT. THE WAVE N OF 13N IS EMBEDDED WITHIN AN AREA OF DEEP LAYER MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY WITH DRIER AIR UNDERCUTTING THE WAVE. CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 14N-19N BETWEEN THE WAVE AXIS AND 60W. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH IS ANALYZED ACROSS AFRICA BUT DOES NOT ENTER THE E TROPICAL ATLC. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 3N-7N BETWEEN 24W-28W AND WITHIN 120 NM ALONG THE COAST OF W AFRICA S OF 10N W OF 10W. ...DISCUSSION... GULF OF MEXICO... BROAD UPPER TROUGH IS MOVING ACROSS THE E CONUS COVERING THE GULF W OF A LINE FROM THE BIG BEND AREA OF FLORIDA TO VERACRUZ MEXICO SUPPORTING A FRONTAL BOUNDARY THAT HAS BECOME QUASI-STATIONARY AT 07/0300 UTC. THE FRONT ENTERS THE GULF WATERS NEAR TAMPA FLORIDA ALONG 25N87W SW TO THE 1008 MB LOW NEAR 20N94W THAT WAS DISCUSSED IN THE SPECIAL FEATURES SECTION ABOVE. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 45/60 NM EITHER SIDE OF THE FRONT. AN UPPER RIDGE IS TO THE SE OF THE FRONT ENHANCING SCATTERED SHOWERS/THUNDERSTORMS WITHIN 75 NM OF LINE FROM FLORIDA BAY THROUGH THE YUCATAN CHANNEL INCLUDING THE LOWER FLORIDA KEYS. DRY AIR ALOFT AND REMARKABLE CLEAR SKIES DOMINATE THE GULF WATERS NW OF A LINE FROM PANAMA CITY FLORIDA ALONG 27N87W TO TAMPICO MEXICO. FRONT WILL REMAIN STATIONARY TODAY AND DISSIPATE THU AND FRI WHILE THE LOW LINGERS IN THE SW GULF THROUGH SUN...WITH THE POTENTIAL TO BECOME A TROPICAL CYCLONE. CARIBBEAN SEA... A WEAK UPPER LOW COVERS THE NW CARIBBEAN CENTERED NEAR THE CAYMAN ISLANDS ENHANCING SCATTERED SHOWERS/THUNDERSTORMS IN THE YUCATAN CHANNEL N OF 20N BETWEEN 84W-87W. THE MONSOON TROUGH EXTENDS ACROSS THE SW CARIBBEAN FROM COLOMBIA NEAR 10N75W INTO THE E PACIFIC REGION NEAR THE PANAMA/COSTA RICA BORDER WITH SCATTERED SHOWERS/THUNDERSTORMS MOSTLY INLAND OVER COLOMBIA AND E PANAMA WITH ISOLATED SHOWERS DRIFTING INTO THE FAR SW CARIBBEAN IN THE GULF OF URABA. DRY STABLE AIR ALOFT DOMINATES THE CARIBBEAN E OF 80W. THIS IS LEAVING THE REMAINDER OF THE CARIBBEAN UNDER REMARKABLY CLEAR SKIES AGAIN TONIGHT WITH THE EXCEPTION OF SOME ISOLATED SHOWERS OVER THE FAR E CARIBBEAN AND THE LESSER ANTILLES DUE TO THE APPROACHING TROPICAL WAVE. THE TROPICAL DEPRESSION IS EXPECTED TO REACH THE W TROPICAL ATLC FRI AS A TROPICAL STORM AND APPROACH THE LEEWARD ISLANDS SAT. THE W ATLC TROPICAL WAVE WILL MOVE NW TOWARD PUERTO RICO THROUGH THU. ATLANTIC OCEAN... A QUASI-STATIONARY FRONT ENTERS THE W ATLC NEAR 32N79W ACROSS FLORIDA INTO THE GULF OF MEXICO NEAR DAYTONA BEACH GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 60 NM OF THE FRONT MAINLY N OF 31N. SIMILAR SHOWERS/THUNDERSTORMS ARE OVER THE N BAHAMA ISLANDS FROM 24N-27N BETWEEN 76W-79W. A SWATH OF DRY STABLE AIR IS TO THE E WITHIN 120 NM OF LINE FROM THE S BAHAMA ISLANDS NEAR 23N73W TO 33N77W. THE UPPER RIDGE ASSOCIATED WITH HURRICANE KATIA COVERS AN AREA FROM 19N-32N BETWEEN 58W-72W. A WEAKENING UPPER LOW IS OVER THE W/CENTRAL ATLC CENTERED NEAR 27N55W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 17N-27N BETWEEN 49W-54W. THIS UPPER LOW APPEARS TO BECOME CUT OFF FROM THE MUCH LARGER UPPER TROUGH THAT COVERS THE REMAINDER OF THE CENTRAL AND INTO E ATLC AND EXTENDS S INTO THE TROPICS BETWEEN 20W-40W N OF T.D. FOURTEEN. A WEAK BROAD SURFACE RIDGE DOMINATES THE ATLC N OF 20N W OF 60W. HURRICANE KATIA WILL MOVE N OF THE AREA EARLY THU. THE FRONT OVER THE W ATLC WILL GRADUALLY DISSIPATE BY THU. SURFACE RIDGE WILL BUILD ACROSS THE W ATLC IN THE WAKE OF KATIA THU THROUGH SAT. T.D. FOURTEEN IS EXPECTED TO REACH THE W TROPICAL ATLC FRI AS A TROPICAL STORM THEN MOVE NW TOWARD THE LEEWARD ISLAND OVER THE WEEKEND. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW