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| #202406 (Received by flhurricane at: 10:55 PM 21.Jul.2008) TCDAT3 TROPICAL STORM CRISTOBAL DISCUSSION NUMBER 13 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL032008 1100 PM EDT MON JUL 21 2008 CRISTOBAL APPEARS TO BE SUCCUMBING TO THE COOLER SSTS AS DEEP CONVECTION HAS SIGNIFICANTLY DECREASED DURING THE LAST 6 HOURS. THE INITIAL INTENSITY IS LOWERED TO 50 KT BASED ON A RECENT QUIKSCAT PASS. GIVEN THE EXTREMELY COLD SSTS THAT CRISTOBAL WILL ENCOUNTER ALONG THE FORECAST TRACK...FURTHER WEAKENING APPEARS LIKELY. THE FLORIDA STATE UNIVERSITY CYCLONE PHASE SPACE DIAGRAM INDICATES THE SYSTEM WILL BE EXTRATROPICAL IN ABOUT 36 HOURS. HOWEVER...IF THE PRESENT TREND IN CONVECTION CONTINUES...CRISTOBAL COULD BECOME A REMNANT LOW PRIOR TO ITS TRANSITION TO AN EXTRATROPICAL CYCLONE. REGARDLESS...SIGNIFICANT RESTRENGTHENING DOES NOT APPEAR LIKELY AT THIS TIME DUE TO LACK OF BAROCLINIC FORCING. CRISTOBAL CONTINUES TO ACCELERATE EAST-NORTHEASTWARD WITHIN THE DEEP-LAYER SOUTHWESTERLY FLOW AHEAD OF A TROUGH OVER THE EASTERN UNITED STATES...AND THE INITIAL MOTION ESTIMATE IS NOW 060/14. TRACK MODELS ARE IN GOOD AGREEMENT ON A GRADUAL TURN EASTWARD AT DAY TWO AS CRISTOBAL MOVES AROUND THE NORTH SIDE A RIDGE OVER THE CENTRAL ATLANTIC. THEREAFTER...GUIDANCE DIVERGES DUE TO DIFFERING FORECASTS OF A TROUGH...AND ITS ASSOCIATED SURFACE FRONT...WHICH AMPLIFIES SOUTHWARD OVER THE NORTHEAST ATLANTIC. CONSIDERING THE UNCERTAINTY...THE OFFICIAL FORECAST LIES NEAR THE CENTER OF THE DYNAMICAL MODEL CONSENSUS AT DAYS 3 AND 4. FORECAST POSITIONS AND MAX WINDS INITIAL 22/0300Z 37.7N 69.8W 50 KT 12HR VT 22/1200Z 39.8N 67.1W 45 KT 24HR VT 23/0000Z 42.5N 62.7W 40 KT 36HR VT 23/1200Z 44.0N 57.9W 35 KT...EXTRATROPICAL 48HR VT 24/0000Z 44.0N 52.8W 35 KT...EXTRATROPICAL 72HR VT 25/0000Z 41.0N 44.5W 30 KT...EXTRATROPICAL 96HR VT 26/0000Z 37.5N 41.0W 25 KT...EXTRATROPICAL 120HR VT 27/0000Z...DISSIPATED $$ FORECASTER RHOME |
