000 AXNT20 KNHC 091802 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SUN SEP 09 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS... WEATHER OBSERVATIONS...AND RADAR. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1645 UTC. ...SPECIAL FEATURE... TROPICAL STORM GABRIELLE IS CENTERED NEAR 35.3N 76.3W OR ABOUT 40 NM WNW OF CAPE HATTERAS NORTH CAROLINA AT 09/1800 UTC MOVING N AT 10 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. PLEASE REFER TO THE NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC AND THE PUBLIC ADVISORY UNDER MIATCPAT2/WTNT32 KNHC FOR MORE DETAILS. RADAR IMAGERY AND RECONNAISSANCE AIRCRAFT DATA INDICATED GABRIELLE MADE LANDFALL ALONG THE NORTH CAROLINA COAST AT 1545 UTC ALONG THE CAPE LOOKOUT NATIONAL SEASHORE. HOWEVER...THE STRONGEST WINDS AND HEAVIEST RAINS ARE JUST REACHING THE COAST AND WILL BE SPREADING FURTHER ONSHORE DURING THE NEXT FEW HOURS. GABRIELLE IS EXPECTED TO TURN TO THE NNE LATER TODAY AND TOWARD THE NE TONIGHT. GABRIELLE HAS BEEN INTERACTING WITH LAND OVER THE PAST FEW HOURS AND NO ADDITIONAL STRENGTHENING IS EXPECTED. HEAVY RAIN AND EMBEDDED THUNDERSTORMS ARE MOSTLY OFFSHORE FROM 33N-35N BETWEEN 75W-77W WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS...IN SPIRAL RAINBANDS COVER A LARGER AREA FROM 32N-37N BETWEEN 74W-78W. GABRIELLE IS EXPECTED TO PRODUCE TOTAL RAINFALL ACCUMULATIONS OF 1 TO 3 INCHES ACROSS COASTAL SECTIONS OF NORTH CAROLINA AND FAR SOUTHEASTERN VIRGINIA...WITH ISOLATED MAXIMUM AMOUNTS OF 5 INCHES. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 33W/34W S OF 16N MOVING W NEAR 15 KT WITH A 1012 MB LOW ALONG THE WAVE NEAR 10N. WAVE REMAINS EMBEDDED IN A BROAD MONSOON-LIKE TROUGH THAT EXTENDS WSW FROM THE AFRICAN COAST NEAR 12N16W TO 7N45W. LARGE CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 90 NM OF LINE FROM 13N32W TO 9N39W. WHILE THERE ARE NO SIGNS OF SIGNIFICANT ORGANIZATION AT THIS TIME...THIS SYSTEM DOES HAVE SOME POTENTIAL FOR SLOW DEVELOPMENT DURING THE NEXT FEW DAYS. TROPICAL WAVE IS ALONG 57W S OF 21N MOVING W 10-15 KT WITH A WEAKENING 1012 MB LOW ALONG THE WAVE NEAR 14N. THE LOW LEVEL SWIRL THAT HAS BEEN ANALYZED OVER THE PAST 12 HOURS IS WEAK AND LOOKS TO BE DISSIPATING. HOWEVER...AN AREA OF DEEP CONVECTION WITH MID LEVEL ROTATION IS FORMING ALONG THE N PORTION OF THE WAVE AND A SECOND SURFACE LOW IS EXPECTED TO FORM THERE. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 16N-20N BETWEEN 55W-58W WITH SCATTERED SHOWERS/THUNDERSTORMS FROM 12N-16N BETWEEN 57W-60W. TROPICAL WAVE IS ALONG 91W S OF 22N MOVING W 10-15 KT. THIS WAVE IS WELL-DEFINED IN THE E PACIFIC REGION WITH NO ASSOCIATED SHOWERS/DEEP CONVECTION IN THE GULF OF MEXICO AND OVER S MEXICO. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 14N15W 11N31W 8N40W 9N62W. IN ADDITION TO ACTIVITY ASSOCIATED WITH THE TROPICAL WAVES...CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE WITHIN 180 NM N OF THE AXIS FROM 40W-50W. SCATTERED MODERATE CONVECTION IS WITHIN 75/90 NM OF 9N FROM 20W-27W. SCATTERED THUNDERSTORMS DOT THE AREA FROM 6N-16N E OF 25W TO THE COAST OF W AFRICA AND FROM 4N-9N BETWEEN 34W-50W. DISCUSSION... GULF OF MEXICO... THE S GULF IS VERY ACTIVE TODAY AS A SURFACE TROUGH EXTENDS FROM THE W ATLC ACROSS CENTRAL FLORIDA FROM DAYTONA BEACH TO FORT MYERS CONTINUING ACROSS THE GULF ALONG 26N84W 26N87W TO 24N91W. THIS SURFACE TROUGH IS ASSOCIATED WITH AN UPPER TROUGH THAT EXTENDS ACROSS NE FLORIDA A MID/UPPER LEVEL LOW IN THE S GULF NEAR 22N91W AND IS BEING MONITORED BUT DEVELOPMENT IS NOT EXPECTED AT THIS TIME. THE SURFACE TROUGH IS MOVING NW WITH CLUSTERS OF HEAVY SHOWERS/THUNDERSTORMS ARE S OF THE TROUGH AND DRY UPPER AIR IS BEING ADVECTED N OF THE TROUGH. THE REMAINDER OF THE GULF IS RATHER TRANQUIL WITH LIGHT/MODERATE WINDS. THE EXCEPTION IS A SMALL AREA OF THUNDERSTORMS N OF THE ABOVE SURFACE TROUGH WITHIN A 75 NM RADIUS OF 27N85W AND SCATTERED SHOWERS/THUNDERSTORMS IN THE SW GULF FROM 20N-23N BETWEEN 93W AND THE COAST OF MEXICO ASSOCIATED WITH THE MID/UPPER LOW/TROUGH. CARIBBEAN SEA... AN UPPER RIDGE COVERS THE W CARIBBEAN EXTENDING FROM CENTRAL AMERICA ACROSS CENTRAL CUBA PRODUCING ENOUGH DIFFLUENCE BETWEEN THE UPPER TROUGH OF THE GULF OF MEXICO TO GENERATE SCATTERED SHOWERS/THUNDERSTORMS N OF 20N ACROSS CUBA AND THROUGH THE YUCATAN CHANNEL W OF 80W TO OVER THE YUCATAN PENINSULA. WEAK UPPER TROUGH EXTENDS ACROSS THE LEEWARD ISLANDS TO NEAR 14N80W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF A LINE FROM COLOMBIA NEAR 11N75W TO NICARAGUA NEAR 14N84W INCLUDING W PANAMA. MODERATE/STRONG EASTERLY TRADE WINDS ACROSS THE REGION ARE GENERATING A MALL AREA OF SCATTERED SHOWERS/THUNDERSTORMS WITHIN 60 NM OF LINE FROM 14N73W TO 13N78W. THE FAR E CARIBBEAN IS UNDER SOMEWHAT DRY STABLE AIR BUT CONDITIONS ARE EXPECTED TO TURN WET WITH THE APPROACH OF THE TROPICAL WAVE CURRENTLY ALONG 57W. WIDELY ISOLATED SHOWERS/THUNDERSTORMS DOT THE REMAINDER OF THE CARIBBEAN W OF 65W. ATLANTIC OCEAN... T.S. GABRIELLE IS THE PRIMARY FOCUS TODAY AS IT CONTINUES ACROSS THE OUTER BANKS OF NORTH CAROLINA...SEE SPECIAL FEATURES ABOVE. AN UPPER TROUGH EXTENDS FROM 31N79W ACROSS NE FLORIDA INTO THE GULF OF MEXICO WITH AN ASSOCIATED SURFACE TROUGH EXTENDING FROM 30N79W ACROSS FLORIDA NEAR DAYTONA BEACH. AN UPPER RIDGE EXTENDS ACROSS THE REMAINDER OF THE W ATLC FROM THE CARIBBEAN ACROSS CENTRAL CUBA TO BEYOND 32N72W. THIS IS PRODUCING ENOUGH DIFFLUENCE TO GENERATE SCATTERED SHOWERS/THUNDERSTORMS FROM 23N-26N W OF 78W TO OVER S FLORIDA WITH ISOLATED SHOWERS/ THUNDERSTORMS DOTTING THE AREA N OF 26N W OF 73W. A DEEP LAYERED RIDGE IS OVER THE W/CENTRAL ATLC ANCHORED BY A 1024 MB HIGH N OF BERMUDA. A DEEP LAYERED TROUGH IS OVER THE CENTRAL ATLC WITH AN ASSOCIATED COLD FRONT ENTERING THE AREA NEAR 32N38W EXTENDING SW TO 26N50W BECOMING NEAR STATIONARY ALONG 25N56W TO 26N62W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 120/150 NM S AND E OF THE FRONTAL BOUNDARY. TYPICAL E/W UPPER RIDGE DOMINATES THE REMAINDER OF THE ATLC WITH DRY STABLE AIR AND A SURFACE RIDGE EXTENDING THROUGH 32N24W TO A 1022 MB HIGH NEAR 29N28W TO NEAR 20N50W. $$ WALLACE