|
Show Selection: |
| #35084 (Received by flhurricane at: 5:08 AM 24.Jul.2005) TCDAT1 TROPICAL STORM FRANKLIN DISCUSSION NUMBER 12 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 AM EDT SUN JUL 24 2005 RECONNAISSANCE REPORTS UP UNTIL 06Z INDICATED THAT FRANKLIN WAS...AT LEAST TO THAT POINT...HOLDING ITS OWN AGAINST NORTHWESTERLY SHEAR. MAXIMUM FLIGHT LEVEL WINDS DURING THE PAST SEVERAL HOURS WERE 58 KT...AND A DROPSONDE AT 0516Z REPORTED 49 KT AT THE SURFACE IN THE SOUTHEAST QUADRANT. THE LAST CENTRAL PRESSURE REPORTED BY THE AIRCRAFT WAS BACK DOWN TO 1001 MB. BASED ON THESE DATA...THE INITIAL INTENSITY WILL BE HELD AT 55 KT. SINCE THE AIRCRAFT LEFT THE CYCLONE HOWEVER...THE CENTER HAS BECOME MOSTLY EXPOSED ON THE NORTHWEST EDGE OF A SMALL AREA OF COLD CONVECTION...WITH A RAGGED BAND LOCATED WELL TO THE SOUTH AND SOUTHWEST OF THE CENTER. THE NEXT RECONNAISSANCE FLIGHT THIS AFTERNOON WILL LIKELY FIND A WEAKER SYSTEM. THE MOTION HAS BEEN UNSTEADY BUT A SMOOTHED ESTIMATE IS 070/8. THERE IS STILL CONSIDERABLE UNCERTAINTY IN THE FORECAST TRACK AS THE DYNAMICAL MODELS OFFER WIDELY DIFFERENT SCENARIOS. THE UKMET AND NOGAPS MAINTAIN A STRONG CYCLONE AND TAKE IT SLOWLY NORTHEASTWARD ON THE NORTHWEST OF A BUILDING SUBTROPICAL RIDGE. THE OTHER EXTREME IS OFFERED BY THE GFS...WHICH CONTINUES WITH A RAPID EAST-NORTHEASTWARD PROGRESSION OF A WEAK AND DECOUPLED SYSTEM. I LIKE THE IDEA OF A WEAK AND SHALLOW VORTEX...ESPECIALLY GIVEN CURRENT TRENDS AND THE APPROACH OF DRY UPPER-LEVEL WESTERLY FLOW...AS SEEN IN WATER VAPOR IMAGERY. HOWEVER...THE GFS SEEMS WAY TOO FAST AND I HAVE BASED THE OFFICIAL FORECAST MORE ON THE SHALLOW BAM AND FSU SUPERENSEMBLE...AS WELL AS CONTINUITY WITH THE PREVIOUS ADVISORY. THE UPPER ENVIRONMENT LOOKS TO BE VERY HOSTILE FOR AT LEAST THE NEXT 24-48 HOURS...AND IF THE FORECAST TRACK IS AT ALL CORRECT... FRANKLIN WILL BE MOVING OVER COOLER WATERS BY LATE IN THE FORECAST PERIOD. CONSEQUENTLY...A GRADUAL DECLINE IS FORECAST...BUT THE CYCLONE COULD DISSIPATE MUCH MORE QUICKLY THAN INDICATED BY THE OFFICIAL FORECAST. FORECASTER FRANKLIN FORECAST POSITIONS AND MAX WINDS INITIAL 24/0900Z 30.5N 72.3W 55 KT 12HR VT 24/1800Z 30.9N 70.8W 50 KT 24HR VT 25/0600Z 31.3N 69.2W 45 KT 36HR VT 25/1800Z 31.6N 67.8W 45 KT 48HR VT 26/0600Z 32.0N 66.5W 40 KT 72HR VT 27/0600Z 34.0N 63.5W 35 KT 96HR VT 28/0600Z 36.0N 60.0W 30 KT 120HR VT 29/0600Z 39.0N 54.5W 25 KT...DISSIPATING |
