000 AXNT20 KNHC 120549 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT TUE SEP 12 2006 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN 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...WEATHER OBSERVATIONS...RADAR... AND METEOROLOGICAL ANALYSIS. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0530 UTC. ...SPECIAL FEATURES... THE CENTER OF HURRICANE FLORENCE AT 12/0300 UTC WAS LOCATED NEAR 35.8N 63.9W OR ABOUT 245 MILES...315 KM...NORTH-NORTHEAST OF BERMUDA. FLORENCE IS MOVING TOWARD THE NORTH-NORTHEAST NEAR 16 KT...30 KM/HR. THIS GENERAL MOTION WITH SOME INCREASE IN FORWARD SPEED IS EXPECTED TUESDAY. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 974 MB. MAXIMUM SUSTAINED WINDS ARE NEAR 75 KT WITH GUSTS TO 90 KT. FLORENCE IS A CATEGORY ONE HURRICANE ON THE SAFFIR-SIMPSON SCALE. SOME WEAKENING IS FORECAST DURING THE NEXT 24 HOURS. PLEASE READ THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC OR THE PUBLIC ADVISORY UNDER MIATCPAT1/WTNT31 KNHC FOR MORE DETAILS. FLORENCE IS A LARGE HURRICANE. HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 70 MILES...110 KM...FROM THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 290 MILES...465 KM. WINDS AT BERMUDA WILL CONTINUE TO DECREASE THRU THE NIGHT. FLORENCE HAS BECOME INCREASINGLY LESS HEALTHY-LOOKING ON SATELLITE IMAGERY WITH MOST OF THE CONVECTION TO THE N OF THE CENTER. THIS SYSTEM WILL SLOWLY BEGIN TO LOSE ITS TROPICAL CHARACTERISTICS AND BECOME A STRONG EXTRATROPICAL SYSTEM IN ABOUT 2 DAYS. THE CENTER OF TROPICAL STORM GORDON AT 12/0300 UTC IS NEAR 22.1N 57.9W OR ABOUT 425 MILES/690 KM NORTHEAST OF THE LEEWARD ISLANDS. GORDON IS MOVING TOWARD THE NORTHWEST NEAR 8 KT...15 KM/HR...AND THIS MOTION IS EXPECTED TO CONTINUE FOR THE NEXT 24 HOURS. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. MAXIMUM SUSTAINED WINDS HAVE INCREASED TO NEAR 50 KT WITH GUSTS TO 60 KT. TROPICAL STORM FORCE WINDS EXTEND OUTWARD 75 NM IN THE NE AND 25 NM IN THE SE QUADRANT. PLEASE READ THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC AND THE PUBLIC ADVISORY MIATCPAT2/WTNT32 KNHC FOR MORE DETAILS. GORDON APPEARS TO BE ON A STRENGTHENING TREND WITH CONVECTION INCREASING AND CONSOLIDATING. THE COLDEST CLOUD TOPS ARE BETWEEN -75 AND -80 C NEAR THE CENTER. THE TROPICAL CYCLONE WILL LIKELY SPEND ITS LIFE OVER WATER AS IT IS TRACKING TOWARDS A PROFOUND WEAKNESS LEFT FROM FLORENCE. SOME STRENGTHENING IS FORECAST DURING THE NEXT 24 HOURS AND GORDON COULD BECOME A HURRICANE IN A DAY OR TWO. A STRONG TROPICAL WAVE IS LOCATED JUST OFF THE COAST OF AFRICA ALONG 17W/18W S OF 18N. A 1009 MB LOW PRES SYSTEM IS ALONG THE WAVE NEAR 12N. THIS SYSTEM IS FAIRLY LARGE WITH ITS BROAD CYCLONIC ROTATION COVERING AN AREA OF A FEW HUNDRED NM. SHOWER ACTIVITY WAS GENERALLY ON THE DECREASE THIS EVENING...HOWEVER SCATTERED MODERATE CONVECTION HAS FIRED OVER THE LAST FEW HOURS TO THE W OF THE ANALYZED SFC LOW FROM 10N-14N BETWEEN 20W-22W. THIS SYSTEM HAS THE POTENTIAL TO DEVELOP DURING THE NEXT DAY OR TWO AS IT MOVES WESTWARD 10-15 KT. ...TROPICAL WAVES... A TROPICAL IS ALONG 34W S OF 17N MOVING W 10 TO 15 KT. SLIGHT LOW-MID LEVEL CYCLONIC TURNING IS NOTED ABOUT THE AXIS N OF 11N. THE BEST TURNING APPEARS TO BE MAINLY IN THE MID-LEVELS JUST AHEAD OF THE ANALYZED POSITION NEAR 7N. ONLY ISOLATED SHOWERS ARE NEAR THE WAVE AXIS. DESPITE THE POOR STRUCTURE OF THE WAVE...THERE IS GOOD CONFIDENCE IN THE PLACEMENT OF THE AXIS USING METEOSAT8 HOVMOLLER DIAGRAMS. A TROPICAL WAVE IS ALONG 45W S OF 16N MOVING W NEAR 10 KT. THIS WAVE IS LOW AMPLITUDE AND DIFFICULT TO LOCATE WITH HIGH LEVEL CLOUDS STREAMING ACROSS THIS FEATURE IN A PRONOUNCED SWLY FLOW MASKING ANY LOW-MID LEVEL SIGNATURE. SCATTERED SHOWERS AND TSTMS HAVE DIMINISHED A GREAT DEAL SINCE YESTERDAY BUT APPEAR TO BE MAKING A SLIGHT COMEBACK OVER THE PAST HOUR OR TWO FROM 12N-15N BETWEEN 43W-49W. A TROPICAL WAVE HAS MOVED INTO THE E CARIBBEAN ALONG 61W S OF 16N MOVING W NEAR 15 KT. THIS WAVE SPLIT SUNDAY EVENING WITH THE NRN EXTENSION NOW T.S. GORDON. THE WAVE IS LOW AMPLITUDE AND BARELY DISCERNIBLE ON NIGHT CHANNEL VIS IMAGES. ONLY ISOLATED SHOWERS ARE IN THE VICINITY OF THE AXIS. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 11N22W 10N31W 9N41W 11N60W. BESIDES FOR THE CONVECTION DISCUSSED IN THE TROPICAL WAVES SECTION...SCATTERED MODERATE CONVECTION IS INLAND OVER SOUTH AMERICA S OF 8N BETWEEN 61W-70W. ...DISCUSSION... THE GULF OF MEXICO... THE WEATHER HAS CHANGED LITTLE ACROSS THE GULF OVER THE PAST FEW DAYS. AN UPPER LEVEL HIGH IS NEARLY STATIONARY OVER CENTRAL MEXICO NEAR 24N103W. THIS ANTICYCLONE HAS RIDGING THAT EXTENDS E ALONG 26N/27N. UPPER DIFFLUENT AIR BETWEEN THE FLOW AROUND THIS HIGH AND THE WESTERLIES OVER THE SRN U.S. IS HELPING TO SUPPORT SCATTERED SHOWERS AND TSTMS BETWEEN 25N-30N ACROSS THE GULF. HOWEVER...MUCH OF THIS HAS BEEN DIMINISHING OVER THE PAST FEW HOURS. THE MOST PERSISTENT ACTIVITY IS IN THE E GULF FROM 26N-28N BETWEEN 83W-86W WHERE UPPER DIFFLUENCE IS SLIGHTLY STRONGER. AN UPPER LEVEL LOW IS MOVING W ENTERING THE BAY OF CAMPECHE WITH WEAKENING SCATTERED SHOWERS ASSOCIATED WITH IT. AT THE SURFACE...HIGH PRES RIDGING EXTENDS FROM SE CANADA AND THE NE U.S. SOUTHWESTWARD INTO THE ERN GULF. E/SE WINDS ARE FAIRLY LIGHT ON THE SW PERIPHERY OF THE SFC RIDGE. THIS RIDGE WILL PUSH E AS A COLD FRONT ENTERS THE N GULF ON WED. SIMILAR WEATHER IS EXPECTED ON MONDAY AS THE UPPER LEVEL PATTERN IS NOT EXPECTED TO CHANGE MUCH. THE CARIBBEAN SEA... QUIET WEATHER CONTINUES IN THE CARIBBEAN TONIGHT WITH PLENTY OF DRY STABLE UPPER LEVEL AIR NOTED ON WATER VAPOR IMAGES W OF 75W. THIS REGION LIES IN AN AREA OF UPPER LEVEL RIDGING WITH AN ANTICYCLONE CENTERED NEAR 20N83W. E OF 75W...BROKEN DEBRIS MOISTURE FROM THE ATLC TROPICAL CYCLONES HAS PUSHED SOUTHWARD BETWEEN AN UPPER LOW JUST N OF THE LEEWARD ISLANDS AND THE UPPER HIGH IN THE NW CARIBBEAN. HOWEVER...DEEP MOISTURE IS VERY LIMITED WITH ONLY ISOLATED SHOWERS FOUND IN THE HIGH LEVEL MOISTURE PLUME. THE ONLY CONVECTION NOTED IN THE REGION IS IN THE SW CARIBBEAN S OF 12N W OF 74W...HIGHLY CONTRIBUTED TO THE ITCZ. AT THE SFC...TRADE WINDS APPEAR TO BE MOSTLY IN THE 10 TO 20 KT RANGE WITH LITTLE CHANGE IN THESE WINDS EXPECTED THRU MID-WEEK. GFS SLOWLY SHIFTS THE DRY AIR W OVER THE NEXT FEW DAYS WITH SOME INCREASE IN TROPICAL MOISTURE ACROSS THE LESSER ANTILLES. THE ATLANTIC OCEAN.. HURRICANE FLORENCE HAS MOVED N OF THE AREA BUT HAS HELPED TO PUSH A SURGE OF N/NE WINDS AND COOLER/DRIER AIR SOUTHWARD OFF THE EAST COAST...AS THE STORM INTERACTS WITH A STRONG 1031 MB HIGH OVER SOUTHEASTERN CANADA. A COLD FRONT HAS BEEN ADDED TO THE 00 UTC ANALYSIS IN ASSOCIATION WITH THIS SURGE OF AIR FROM THE NORTH. A 23Z QUIKSCAT PASS SHOWS THIS SURGE NICELY WITH WINDS IN EXCESS OF 20 KT BEHIND THE SURGE AND 10-15 KT TO THE S. THIS LARGE FETCH OF NE WINDS WILL CONTINUE TO GENERATE A MODERATE TO STRONG NE SWELL FOR THE SW NORTH ATLANTIC THROUGH MIDWEEK...AND DANGEROUS SURF CONDITIONS FOR BEACHES EXPOSED TO NE SWELL. THIS WILL SLOWLY SUBSIDE THROUGH THE SECOND PART OF THE WEEK...SEE STATEMENTS FROM LOCAL WEATHER SERVICE OFFICES FOR MORE INFO. TROPICAL STORM GORDON LIES ABOUT 1000 NM TO THE SE OF THE FLORENCE AND IS TRACKING NW INTO THE PROFOUND WEAKNESS IN THE SUBTROPICAL RIDGE LEFT BEHIND FROM FLORENCE. NUMEROUS MODERATE CONVECTION LIES FROM 21N-24N BETWEEN 55W-59W. A WELL-DEFINED UPPER LEVEL LOW IS SPINNING NEAR 29N39W MOVING WESTWARD. THIS UPPER LOW IS ALSO WEAKENING THE SUBTROPICAL RIDGE. ISOLATED TO SCATTERED SHOWERS ARE SPIRALING CYCLONICALLY AROUND THE LOW FROM 27N-34N BETWEEN 36W-42W. AN UPPER HIGH IS MOVING WESTWARD OFF THE AFRICAN COAST WITH A HIGH CENTER NEAR 25N24W AND RIDGING EXTENDING TO 33W. AT THE SFC...A 1027 MB HIGH IS CENTERED JUST S OF THE AZORES WITH RIDGING COVERING THE CENTRAL AND EASTERN SUBTROPICAL ATLC. $$ CANGIALOSI