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| #201391 (Received by flhurricane at: 10:55 PM 16.Jul.2008) TCDAT2 TROPICAL STORM BERTHA DISCUSSION NUMBER 56 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022008 1100 PM EDT WED JUL 16 2008 BERTHA'S SATELLITE APPEARANCE HAS CONTINUED TO GRADUALLY DEGRADE DURING THE PAST 24 HOURS. THE CYCLONE IS PRODUCING VERY LITTLE DEEP CONVECTION AND THERE ARE VIRTUALLY NO CLOUD TOPS COLDER THAN -50 DEGREES C. DVORAK INTENSITY ESTIMATES HAVE DECREASED TO 45 KT...HOWEVER A QUIKSCAT OVERPASS AT 2156 UTC SUGGESTS THAT THE WINDS REMAIN 55-60 KT...SO THE INITIAL INTENSITY IS UNCHANGED. ALL OF THE INTENSITY GUIDANCE PREDICTS LITTLE CHANGE IN BERTHA'S STRENGTH DURING THE NEXT DAY OR TWO...FOLLOWED BY GRADUAL WEAKENING AS SSTS ALONG THE FORECAST TRACK COOL AND THE SHEAR INCREASES. BERTHA IS FORECAST TO BECOME EXTRATROPICAL IN ABOUT 4 DAYS. BERTHA IS MOVING A LITTLE FASTER TO THE SOUTHEAST...140/7. LITTLE CHANGE HAS BEEN MADE TO THE FORECAST TRACK THROUGH 36 HOURS AS BERTHA IS PREDICTED TO MOVE SOUTHEASTWARD...THEN EASTWARD AROUND THE SOUTHWESTERN PERIPHERY OF A LARGE MID- TO UPPER-LEVEL LOW. THEREAFTER...THE TRACK MODELS ARE IN GOOD AGREEMENT ON A NORTHEASTWARD MOTION...BUT AT VARYING FORWARD SPEEDS. HOWEVER...THE MOST RECENT TRACK GUIDANCE IS IN A LITTLE BETTER AGREEMENT THAN 6 HOURS AGO. THE NEW NHC TRACK IS SIMILAR TO THE PREVIOUS ADVISORY AND IS IN BEST AGREEMENT WITH THE FSU SUPERENSEMBLE...12Z UKMET...AND GFDL...BUT IS SLOWER THAN THE MODEL CONSENSUS. THE 34 AND 50 KT WIND RADII OVER THE EASTERN SEMICIRCLE WERE EXPANDED BASED ON THE SCATTEROMETER DATA. FORECAST POSITIONS AND MAX WINDS INITIAL 17/0300Z 35.4N 59.8W 60 KT 12HR VT 17/1200Z 34.6N 58.9W 60 KT 24HR VT 18/0000Z 34.5N 56.8W 60 KT 36HR VT 18/1200Z 35.5N 54.4W 55 KT 48HR VT 19/0000Z 37.6N 51.7W 55 KT 72HR VT 20/0000Z 42.5N 45.7W 50 KT 96HR VT 21/0000Z 48.0N 39.0W 45 KT...EXTRATROPICAL 120HR VT 22/0000Z 54.5N 30.0W 45 KT...EXTRATROPICAL $$ FORECASTER BROWN |
