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| #58512 (Received by flhurricane at: 10:03 PM 25.Nov.2005) TCDAT3 TROPICAL STORM DELTA DISCUSSION NUMBER 10 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 10 PM EST FRI NOV 25 2005 WIND SHEAR CONTINUES TO RESULT IN THE CONVECTION BEING RELEGATED TO THE EASTERN SEMICIRCLE. THE LOW-LEVEL CENTER IS ALMOST COMPLETELY EXPOSED... BUT THE CONVECTION JUST TO ITS EAST IS STILL FAIRLY DEEP. A QUIKSCAT OVERPASS NEAR 2020Z REVEALED 45 KT WINDS JUST OUTSIDE OF THE CONVECTION... AND THE CLOUD TOPS HAVE COOLED SINCE THEN. DVORAK INTENSITY ESTIMATES BASED ON A SHEAR PATTERN ARE STILL T3.0/45 KT... AND THE ADVISORY INTENSITY IS MAINTAINED AT 50 KT. HOWEVER... A STEADY WEAKENING TREND APPEARS IMMINENT... AS WESTERLY WIND SHEAR IS FORECAST TO STRENGTHEN OVER DELTA DURING THE NEXT 24-36 HOURS AHEAD OF A MID- TO UPPER-LEVEL TROUGH CURRENTLY NORTH OF THE LESSER ANTILLES THAT WILL MOVE EASTWARD AND DEEPEN. THE NEW OFFICIAL FORECAST FOLLOWS THE SHIPS GUIDANCE CLOSELY IN ANTICIPATING DELTA TO REMAIN A TROPICAL STORM FOR ONLY ABOUT 36 MORE HOURS. DELTA HAS BEEN MOVING DUE SOUTHWARD AT ABOUT 6 KT FOR THE PAST SEVERAL HOURS. THE DYNAMICAL MODELS ARE UNANIMOUS IN FORECASTING THIS MOTION TO CEASE SHORTLY AND FOR A NORTHEASTWARD MOTION TO BEGIN SOMETIME WITHIN THE NEXT 24 HOURS. THE MODELS ALSO FORECAST A NEW SURFACE LOW PRESSURE SYSTEM TO FORM WEST OF DELTA IN 36-48 HOURS IN ASSOCIATION WITH THE MID/UPPER-LEVEL TROUGH APPROACHING FROM THE WEST. SINCE DELTA WILL PROBABLY WEAKEN QUITE A BIT DURING THE NEXT COUPLE OF DAYS... IT IS NOT LIKELY TO MOVE AS QUICKLY EASTWARD AS MOST OF THE MODELS ARE SUGGESTING... AND IT COULD EVEN BE DRAWN WESTWARD INTO THE CIRCULATION OF THE NEW LOW PRESSURE SYSTEM FORECAST TO DEVELOP. HOWEVER... THE MODELS THAT DEPICT AN APPROPRIATELY WEAK DELTA ALSO SUGGEST THERE IS ALSO A GOOD CHANCE ITS CLOSED CIRCULATION WILL NOT SURVIVE BEYOND ABOUT 72 HOURS AS BECOMES ENTANGLED IN A FRONTAL ZONE. THIS IS THE SOLUTION SHOWN IN THE OFFICIAL FORECAST. FORECASTER KNABB FORECAST POSITIONS AND MAX WINDS INITIAL 26/0300Z 21.9N 39.8W 50 KT 12HR VT 26/1200Z 22.7N 39.3W 45 KT 24HR VT 27/0000Z 23.8N 38.1W 35 KT 36HR VT 27/1200Z 25.7N 36.1W 35 KT 48HR VT 28/0000Z 28.2N 33.3W 30 KT...EXTRATROPICAL 72HR VT 29/0000Z 29.5N 32.0W 30 KT...EXTRATROPICAL 96HR VT 30/0000Z...ABSORBED BY FRONT |
