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| #34735 (Received by flhurricane at: 5:00 PM 22.Jul.2005) TCDAT1 TROPICAL STORM FRANKLIN DISCUSSION NUMBER 6 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 PM EDT FRI JUL 22 2005 DRY AIR HAS WRAPPED UP THE EAST SIDE AND INTO THE CENTER...WHICH HAS ERODED THE DEEP CONVECTION NEAR THE INNER CORE. BANDING FEATURES HAVE ALSO COME AND GONE DURING THE AFTERNOON IN SATELLITE IMAGERY AND IN THE MELBOURNE RADAR DARA. AROUND 1532Z...AIR FORCE RECON FOUND 53 KT FLIGHT-LEVEL WINDS IN THE SOUTHEAST QUADRANT...WHICH EQUALS A 42-43 KT SURFACE WIND...WHILE THE ONBOARD METEOROLOGIST AGAIN ESTIMATED SURFACE WINDS OF 55-60 IN THE SAME AREA. HOWEVER... THAT CONVECTIVE BAND HAS SINCE DISAPPEARED DUE TO THE DRY AIR...SO THOSE SURFACE WINDS WERE LIKELY ENHANCED BY STRONG DOWNDRAFTS. AS SUCH...THE INTENSITY IS BEING MAINTAINED AT 45 KT...ESPECIALLY SINCE THE PRESSURE HAS NOT FALLEN BELOW 1007 MB...AND THE CYCLONE HAS A RAGGED LOOKING APPEARANCE IN SATELLITE AND RADAR IMAGERY. THE INITIAL MOTION IS 360/08 KT. RECON AND RADAR POSITION ESTIMATES INDICATE FRANKLIN HAS BEEN MOVING NORTHWARD AT A STEADY 8 KT OR SO SINCE ABOUT 14Z. ACCORDING TO THE OVERWHELMING MAJORITY OF THE NHC MODELS...THIS GENERAL MOTION IS EXPECTED TO CONTINUE FOR THE NEXT 24 HOURS WITH A GRADUAL TURN AND ACCELERATION TO THE NORTHEAST AND EAST-NORTHEAST AFTER THAT. WATER VAPOR IMAGERY AND SPECIAL 18Z UPPER-AIR DATA INDICATE THE SHORTWAVE TROUGH OVER THE EASTERN OHIO AND TENNESSEE VALLEYS HAS CONTINUED TO MOVE EAST-SOUTHEASTWARD AND SHOULD BE ALONG THE U.S. EAST COAST BY THIS TIME TOMORROW. IF THE SHORTWAVE IS STRONG ENOUGH...THEN IT MAY ERODE THE SUBTROPICAL RIDGE TO THE NORTH OF FRANKLIN...AND CAPTURE THE CYCLONE AND MOVE IT AWAY FROM THE U.S. HOWEVER...THE GFS... UKMET...AND THE CANADIAN MODELS NOW ONLY TAKE FRANKLIN AS FAR NORTH AS 30N LATITUDE IN 36-48 HOURS...AND THEN LEAVE THE MID-LEVEL CIRCULATION BEHIND WHILE THE LOW-LEVEL CENTER MOVES QUICKLY NORTHEASTWARD AHEAD OF A COLD FRONT. WHILE THIS SCENARIO IS POSSIBLE...IT WOULD MEAN THAT FRANKLIN WOULD CEASE TO EXIST AS A TROPICAL CYCLONE. THOSE MODELS ALSO MOVE THE MID-LEVEL CIRCULATION BACK TO THE SOUTH AND SOUTHWEST AFTER 72 HOURS...MUCH LIKE THE MEDIUM AND DEEP BAM MODELS. HOWEVER...THE OFFICIAL FORECAST TRACK REMAINS SIMILAR TO THE PREVIOUS FORECAST AND IS CLOSE TO THE NHC MODEL CONSENSUS. THE SHEAR ACROSS FRANKLIN HAS INCREASED FROM THE WEST AGAIN DUE TO THE OUTFLOW FROM THE DEEP CONVECTION ASSOCIATED WITH THE STRONG YUCATAN DISTURBANCE. WATER VAPOR IMAGERY ALSO INDICATES FRANKLIN IS GETTING PINCHED FROM THE EAST BY AN UPPER-LEVEL TROUGH DIGGING SOUTHWESTWARD. THE UPPER-LEVEL FLOW PATTERN IS ONLY EXPECTED TO SLOWLY BECOME MORE FAVORABLE FOR INTENSIFICATION TO OCCUR...AND THIS IS REFLECTED IN THE SLOWER THAN NORMAL INTENSIFICATION FORECASTS AS PER THE SHIPS INTENSITY MODEL. THE GFDL BRINGS FRANKLIN UP TO 89 IN 48 HOURS...BUT THIS SEEMS OVERDONE... ESPECIALLY WITH INCREASING WESTERLY MID- TO UPPER-LEVEL FLOW FORECAST TO AFFECT THE SYSTEM AT THAT TIME. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 22/2100Z 27.8N 76.7W 45 KT 12HR VT 23/0600Z 28.9N 76.4W 50 KT 24HR VT 23/1800Z 30.0N 75.4W 55 KT 36HR VT 24/0600Z 30.9N 73.8W 60 KT 48HR VT 24/1800Z 31.5N 72.0W 60 KT 72HR VT 25/1800Z 32.8N 67.6W 60 KT 96HR VT 26/1800Z 34.0N 63.0W 60 KT 120HR VT 27/1800Z 37.0N 56.5W 60 KT |
