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| #91007 (Received by flhurricane at: 5:17 AM 12.Jun.2006) TCDAT1 TROPICAL STORM ALBERTO DISCUSSION NUMBER 9 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL012006 500 AM EDT MON JUN 12 2006 ALTHOUGH THE LAST RECONNAISSANCE AIRCRAFT PASS THROUGH ALBERTO NEAR 05Z FOUND ONLY A FLAT PRESSURE GRADIENT WITH A MINIMUM OF 1006 MB AND NO CLEAR CENTER...THE CYCLONE HAS BECOME BETTER ORGANIZED SINCE THEN. DEEP CONVECTION HAS DEVELOPED AND BUILT WESTWARD AGAINST THE SHEAR...AND THE LOW-CLOUD LINES IN THE NIGHT-VIS IMAGERY SUGGEST THAT A CENTER IS BECOMING BETTER DEFINED JUST TO THE WEST OF THIS CONVECTION. A DROPSONDE ON THE EDGE OF THE CONVECTION REPORTED 40 KT AT THE SURFACE AT 06Z...AND THE PRESSURE AT BUOY 42003 HAS FALLEN TO 1002.9 MB. BASED ON THESE OBSERVATIONS THE ADVISORY INTENSITY HAS BEEN INCREASED TO 45 KT. THE NEXT RECONNAISSANCE AIRCRAFT WILL BE IN THE SYSTEM IN ABOUT THREE HOURS. THE INITIAL MOTION IS 020/7. MODEL GUIDANCE IS NOT IN VERY GOOD AGREEMENT ON THE FUTURE TRACK OF ALBERTO...WHICH IS STILL EMBEDDED IN A ENVIRONMENT OF STRONG SOUTHWESTERLY SHEAR. HOWEVER...THE UKMET AND NOGAPS BOTH DROP AN UPPER LOW INTO THE WESTERN GULF THAT BACKS THE FLOW JUST ENOUGH TO ALLOW A MORE NORTHWARD TRACK THAN THE CURRENT OFFICIAL FORECAST. FOR NOW...THE OFFICIAL FORECAST HAS BEEN SHIFTED JUST A LITTLE TO THE LEFT OF THE PREVIOUS TRACK...AND MOST CLOSELY RESEMBLES THE GFS...WHICH HAD BEEN INDICATING A REDEVELOPMENT OF THE CENTER TO THE NORTHEAST. NONE OF THE GUIDANCE MODELS SUGGEST THAT THE SOUTHWESTERLY SHEAR WILL DECREASE DRAMATICALLY...BUT IF THE UKMET AND NOGAPS ARE CORRECT IT WILL DECREASE ENOUGH TO ALLOW SOME FURTHER ORGANIZATION. THE OFFICIAL FORECAST IS A BLEND OF THE SHIPS AND GFDL GUIDANCE. THE LARGE EXTENT OF TROPICAL STORM FORCE WINDS DICTATES A TROPICAL STORM WARNING AT THIS TIME. THESE WINDS ARE EXPECTED TO REACH THE COAST WELL IN ADVANCE OF THE ARRIVAL OF THE CENTER. FORECASTER FRANKLIN FORECAST POSITIONS AND MAX WINDS INITIAL 12/0900Z 26.2N 87.2W 45 KT 12HR VT 12/1800Z 27.1N 86.7W 50 KT 24HR VT 13/0600Z 28.1N 85.6W 55 KT 36HR VT 13/1800Z 29.5N 83.7W 55 KT 48HR VT 14/0600Z 31.0N 81.5W 45 KT...INLAND 72HR VT 15/0600Z 35.0N 73.5W 45 KT...EXTRATROPICAL 96HR VT 16/0600Z 41.5N 64.0W 45 KT...EXTRATROPICAL 120HR VT 17/0600Z 46.5N 52.0W 45 KT...EXTRATROPICAL |
