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| #58697 (Received by flhurricane at: 3:40 AM 27.Nov.2005) TCDAT3 TROPICAL STORM DELTA DISCUSSION NUMBER 15 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 4 AM EST SUN NOV 27 2005 DELTA CONTINUES TO PRODUCE DEEP CONVECTION WITH CLOUD TOPS TO -70C OR COLDER. IN FACT...THE CONVECTION IS ABOUT AS STRONG AS IT HAS BEEN DURING THE LIFETIME OF THE SYSTEM. DVORAK CLASSIFICATIONS SUGGEST THAT THE STORM MIGHT BE AS STRONGER THAN 35 KT. DVORAK INTENSITY ESTIMATES FOR SHEARED TROPICAL CYCLONES ARE HIGHLY DEPENDENT ON THE LOCATION OF THE CENTER WITH RESPECT TO THE DENSE OVERCAST...AND THE CENTER IS DIFFICULT TO LOCATE. GIVEN THE UNCERTAINTIES...THE WIND SPEED IS KEPT AT 35 KT. WESTERLY SHEAR... ASSOCIATED WITH AN UPPER-TROPOSPHERIC TROUGH TO THE WEST OF DELTA...IS FORECAST TO INCREASE...AND THE CYCLONE WILL BE MOVING OVER PROGRESSIVELY COOLER SEA SURFACE TEMPERATURES. IN VIEW OF THE CURRENT VIGOR OF THE DEEP CONVECTION...HOWEVER...ONLY SLOW WEAKENING IS FORECAST. OUTPUT FROM THE NCEP GLOBAL FORECAST SYSTEM...GFS...SHOWS DELTA INTERACTING WITH A FRONTAL ZONE...AND BECOMING EXTRATROPICAL IN 24 HOURS AND SO DOES THE OFFICIAL FORECAST. THE STORM CONTINUES TO GRADUALLY ACCELERATE AND IS NOW MOVING GENERALLY NORTHEASTWARD NEAR 21 KT. A FURTHER INCREASE IN FORWARD SPEED AND A TURN TOWARD THE EAST IS LIKELY AS DELTA OR ITS EXTRATROPICAL COUNTERPART COMES UNDER THE INFLUENCE OF THE WESTERLIES ASSOCIATED WITH A LARGE LOW PRESSURE SYSTEM OVER WESTERN EUROPE. THE OFFICIAL TRACK FORECAST IS TO THE RIGHT OF THE MODEL CONSENSUS AND SLIGHTLY FASTER...BUT NOT AS FAST AS THE GFS. ALTHOUGH DELTA IS FORECAST TO BECOME EXTRATROPICAL IN 24 HOURS...WINDS TO NEAR GALE FORCE COULD SPREAD ACROSS PORTIONS OF THE CANARY ISLANDS IN 24-36 HOURS. FORECASTER PASCH FORECAST POSITIONS AND MAX WINDS INITIAL 27/0900Z 25.6N 32.8W 35 KT 12HR VT 27/1800Z 27.4N 29.6W 35 KT 24HR VT 28/0600Z 28.8N 24.0W 35 KT...EXTRATROPICAL 36HR VT 28/1800Z 28.8N 17.5W 30 KT...EXTRATROPICAL 48HR VT 29/0600Z 28.8N 11.5W 30 KT...EXTRATROPICAL 72HR VT 30/0600Z...DISSIPATED |
