000 AXNT20 KNHC 091201 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT FRI SEP 09 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 1145 UTC. ...SPECIAL FEATURES... TROPICAL STORM NATE IS CENTERED NEAR 20.0N 92.4W AT 09/1200 UTC OR ABOUT 125 MI...200 KM W OF CAMPECHE AND 180 MI...290 KM NE OF COATZACOALCOS MEXICO. NATE IS MOVING NW AT 2 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 998 MB. THE MAXIMUM SUSTAINED WIND SPEED IS 55 KT WITH GUSTS TO 65 KT. PLEASE SEE THE LATEST INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADER MIATCPAT5/WTNT35 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADER MIATCMAT5/ WTNT25 KNHC FOR MORE DETAILS. NATE HAS WEAKENED SOMEWHAT OVERNIGHT WITH THE SCATTERED MODERATE/ISOLATED STRONG CONVECTION CONFINED IN CLOSE PROXIMITY OF THE CENTER. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 24N TO INLAND OVER MEXICO AND THE YUCATAN PENINSULA BETWEEN 89W-95W. TROPICAL STORM MARIA IS CENTERED NEAR 14.0N 56.9W AT 09/1200 UTC OR ABOUT 185 MI...295 KM ENE OF BARBADOS AND 390 MI...630 KM SE OF THE LEEWARD ISLANDS MOVING W-NW AT 16 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1003 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 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. CONVECTION HAS INCREASED TONIGHT BUT MARIA STILL APPEARS RATHER DISORGANIZED ON SATELLITE IMAGERY. SCATTERED/NUMEROUS STRONG CONVECTION IS FROM 13N-15N BETWEEN 53W-58W. SCATTERED/HEAVY SHOWERS WITH EMBEDDED THUNDERSTORMS COVERS THE AREA FROM 11N-19N BETWEEN 49W-58W AND FROM 12N-16N BETWEEN INCLUDING THE WINDWARD ISLANDS. AT 09/0900 UTC HURRICANE KATIA WAS CENTERED NEAR 37.6N 67.5W OR ABOUT 345 NM N-NW OF BERMUDA AND ABOUT 455 NM SSW OF HALIFAX NOVA SCOTIA MOVING NE AT 21 KT. ESTIMATED MINIMUM CENTRAL PRESSURE WAS 967 MB...WITH MAXIMUM SUSTAINED WIND SPEED OF 75 KT WITH GUSTS TO 90 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. KATIA IS BEGINNING TO MOVE INTO COOLER WATERS. KATIA IS FORECAST TO BECOME POST-TROPICAL IN ABOUT 36 HOURS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 26N-41N BETWEEN 65W-70W. LARGE SWELLS GENERATED BY KATIA WILL CONTINUE TO AFFECT MOST OF THE EAST COAST OF THE UNITED STATES AND BERMUDA. 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 WAVES... TROPICAL WAVE IN THE E TROPICAL ATLC IS ANALYZED FROM 16N30W TO 3N36W MOVING W NEAR 15 KT. WAVE IS EMBEDDED WITHIN AN AREA OF DEEP LAYER MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY AND IS WELL DEFINED IN THE UPPER LEVEL SATELLITE WINDS. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 200 NM W OF THE WAVE BETWEEN 11N-15N AND ISOLATED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 200 NM NM EITHER SIDE OF THE WAVE S OF 11N. TROPICAL WAVE IN THE W ATLC/CARIBBEAN IS ANALYZED FROM 23N70W TO 14N72W MOVING W-NW NEAR 15 KT. WAVE IS EMBEDDED WITHIN AN AREA OF DEEP LAYER MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY AND IS WELL DEFINED IN THE UPPER LEVEL SATELLITE WINDS. WAVE IS INTERACTING WITH THE MONSOON TROUGH S OF 16N. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 60 NM OF 17N BETWEEN 71W-76W AND FROM 11N-16N BETWEEN 73W-78W. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH IS ANALYZED ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 14N17W TO 11N20W. THE MONSOON TROUGH AND ITCZ AXIS HAS BEEN DISRUPTED BY THE LACK OF CONFLUENCE IN THE TRADE WINDS AND THE PRESENCE OF TROPICAL STORM MARIA. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 150 NM OF LINE FROM 5N40W TO 10N46W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 5N-9N BETWEEN THE COAST OF W AFRICA AND 17W. ...DISCUSSION... GULF OF MEXICO... THE PRIMARY CONCERN FOR THE S GULF WATERS OF THE GULF CONTINUES TO BE TROPICAL STORM NATE...SEE SPECIAL FEATURES SECTION ABOVE. A BROAD UPPER TROUGH COVERS THE E CONUS INTO THE N GULF N OF 25N AND SUPPORTING A DISSIPATING QUASI-STATIONARY FRONT THAT AT 09/0900 UTC ENTERS THE GULF WATERS NEAR TAMPA FLORIDA TO 25N89W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 90 NM EITHER SIDE OF THE FRONT. AN UPPER RIDGE EXTENDS FROM THE YUCATAN CHANNEL NE ACROSS THE FLORIDA KEYS AND THE STRAITS OF FLORIDA GENERATING ISOLATED SHOWERS S OF 26N E OF 85W. DRY AIR ALOFT REMAINS NW OF A LINE FROM THE BIG BEND AREA OF FLORIDA TO TUXPAN MEXICO GIVING THAT AREA REMARKABLE CLEAR SKIES AGAIN THIS MORNING. NATE IS FORECAST TO SLOWLY INTENSIFY AND DRIFT NW THROUGH THE WEEKEND INTO MEXICO LATE SUN/EARLY MON. THE FRONT WILL DISSIPATE THROUGH SAT. CARIBBEAN SEA... WEAK UPPER FLOW DOMINATES THE CARIBBEAN. THE MONSOON TROUGH EXTENDS ACROSS THE SW CARIBBEAN FROM COLOMBIA NEAR 11N75W ALONG 10N81W INTO THE E PACIFIC REGION OVER COSTA RICA NEAR 10N84W AND IS BEGINNING TO INTERACT WITH THE TROPICAL WAVE OVER THE CENTRAL CARIBBEAN. ISOLATED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS S OF 11N BETWEEN COLOMBIA AND COSTA RICA. THE DRY STABLE AIR ALOFT IS CONFINED TO PORTIONS OF THE NW CARIBBEAN N OF 16N BETWEEN 80W-86W LEAVING THAT AREA UNDER REMARKABLY CLEAR SKIES AGAIN THIS MORNING. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE INT HE GULF OF HONDURAS FROM 17N-20N W OF 86W TO THE COAST OF THE YUCATAN PENINSULA. SIMILAR ACTIVITY IS WITHIN 60 NM OF THE CAYMAN ISLANDS. EASTERLY TRADE WINDS ARE USHERING IN ISOLATED LOW LEVEL SHOWERS/THUNDERSTORMS ACROSS THE E CARIBBEAN E OF 70W. MARIA IS EXPECTED TO MOVE ACROSS THE NE CARIBBEAN FRI NIGHT THROUGH SAT NIGHT THEN E OF THE BAHAMAS. THE TROPICAL WAVE WILL DRIFT ACROSS THE CARIBBEAN THROUGH THE FIRST OF NEXT WEEK. ATLANTIC OCEAN... A BROAD UPPER TROUGH THAT COVERS THE E CONUS TO ALONG THE EASTERN SEABOARD S OF VIRGINIA TO NE FLORIDA SUPPORTING A COLD FRONT THAT ENTERS THE REGION NEAR 32N72W TO 30N75W WHERE IT CONTINUES AS A DISSIPATING STATIONARY FRONT ACROSS FLORIDA INTO THE GULF OF MEXICO BETWEEN DAYTONA BEACH AND MELBOURNE. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 60/75 NM OF THE FRONT W OF 76W. A WEAKENING CUTOFF UPPER LOW IS NE OF THE VIRGIN ISLANDS CENTERED NEAR 23N61W GENERATING SCATTERED SHOWERS/THUNDERSTORMS FROM 19N-25N BETWEEN 63W-70W. A BROAD UPPER TROUGH COVERS THE REMAINDER OF THE CENTRAL AND INTO E ATLC BETWEEN 25W-45W N OF TROPICAL STORM MARIA SUPPORTING A COLD FRONT ALONG THE N PERIPHERY OF THE DISCUSSION AREA BETWEEN 36W-50W AND A SURFACE TROUGH THAT EXTENDS FROM 31N35W TO 26N40W. A WEAK BROAD SURFACE RIDGE CONTINUES TO BUILD OVER THE W ATLC IN THE WAKE OF HURRICANE KATIA AND S OF THE W ATLC FRONTAL BOUNDARY ANCHORED BY A 1021 MB HIGH IN THE W/CENTRAL ATLC NEAR 32N57W AND A SECOND RIDGE EXTENDING OVER THE E ATLC S OF FRONT ALONG THE N PERIPHERY OF THE CENTRAL/E ATLC TO A 1018 MB HIGH IN THE E ATLC NEAR 28N29W. THE SURFACE RIDGE WILL CONTINUE TO BUILD ALONG 27N THROUGH FRI NIGHT THEN LIFT N OF THE AREA ON MON. TROPICAL STORM MARIA WILL MOVE THROUGH THE NE CARIBBEAN FRI NIGHT THROUGH SAT NIGHT THEN E OF THE BAHAMAS THROUGH THE FIRST OF NEXT WEEK. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW/FG