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| #151916 (Received by flhurricane at: 4:34 PM 21.Sep.2007) TCDAT5 TROPICAL DEPRESSION TEN DISCUSSION NUMBER 2 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL102007 500 PM EDT FRI SEP 21 2007 THE BAND IN THE EASTERN SEMICIRCLE OF THE DEPRESSION HAS LARGELY DISSIPATED...WHILE CONVECTION OVER THE CENTER HAS INCREASED... ALBEIT MODESTLY. ADDITIONAL SATELLITE...BUOY...AND RECONNAISSANCE OBSERVATIONS HAVE CONFIRMED THAT A SINGLE WELL-DEFINED LOW-LEVEL CENTER EXISTS. IN ADDITION...WATER VAPOR IMAGERY INDICATES THAT THE LOW-LEVEL VORTEX IS SEPARATING FROM THE UPPER-LOW. CONSEQUENTLY...THE STATUS OF THE CYCLONE IS NOW JUDGED TO BE TROPICAL. THE CENTRAL PRESSURE HAS REMAINED FAIRLY STEADY TODAY. EARLIER FLIGHT-LEVEL DATA IN THE BAND TO THE EAST OF THE CENTER SUGGESTED WINDS MIGHT HAVE BEEN AT TROPICAL STORM FORCE...ALTHOUGH DROPSONDES IN THE BAND DID NOT INDICATE THAT MUCH WIND. IN ANY EVENT...THE BAND HAS SINCE WEAKENED...AND THE INITIAL INTENSITY ESTIMATE REMAINS 30 KT. BASED ON TODAY'S AIRCRAFT FIXES...THE INITIAL MOTION ESTIMATE IS 300/8. THE FORECAST SCENARIO IS BASICALLY UNCHANGED...WITH THE DEPRESSION EXPECTED TO CONTINUE MOVING WEST-NORTHWESTWARD TO THE SOUTH OF A MID-LEVEL RIDGE OF HIGH PRESSURE STRETCHING NORTHEASTWARD FROM TEXAS. MODEL GUIDANCE REMAINS IN GOOD AGREEMENT AND THE OFFICIAL FORECAST FOLLOWS THE DYNAMICAL MODEL CONSENSUS. BECAUSE THE FORECAST TRACK IS NEARLY PARALLEL TO THE COASTLINE...A LANDFALL LOCATION IS DIFFICULT TO PINPOINT. AFTER LANDFALL...AS THE RIDGE BUILDS EASTWARD...THE DEPRESSION OR ITS REMNANTS SHOULD TURN NORTHWESTWARD AND THEN NORTHWARD. THE UPPER FLOW OVER THE DEPRESSION NOW IS LIGHT EASTERLY BUT NOT VERY DIFLUENT. WITH A RELATIVELY WEAK CONVECTIVE CORE AND LIMITED UPPER-AIR SUPPORT...IT WOULD NOT SEEM AS THOUGH MUCH INTENSIFICATION IS IN ORDER PRIOR TO LANDFALL. ALL THE OBJECTIVE GUIDANCE INDICATES THAT THE SYSTEM SHOULD MAKE LANDFALL AS A WEAK TROPICAL STORM. IF THE DEPRESSION MOVES A LITTLE TO THE LEFT OF THE FORECAST TRACK IT WOULD REMAIN OVER WATER LONGER THAN FORECAST...WHICH COULD ALLOW THE SYSTEM TO GET A LITTLE STRONGER THAN FORECAST. FORECAST POSITIONS AND MAX WINDS INITIAL 21/2100Z 29.9N 86.4W 30 KT 12HR VT 22/0600Z 30.3N 87.6W 35 KT...INLAND 24HR VT 22/1800Z 30.7N 89.5W 35 KT...INLAND 36HR VT 23/0600Z 31.5N 92.0W 30 KT...INLAND 48HR VT 23/1800Z...DISSIPATED $$ FORECASTER FRANKLIN |
