|
Show Selection: |
| #201302 (Received by flhurricane at: 10:40 AM 16.Jul.2008) TCDAT2 TROPICAL STORM BERTHA DISCUSSION NUMBER 54 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022008 1100 AM EDT WED JUL 16 2008 THE SATELLITE PRESENTATION OF BERTHA HAS DEGRADED SINCE YESTERDAY WITH AN ELONGATED APPEARANCE. HOWEVER...A QUIKSCAT PASS AT 0938 UTC SHOWED MAXIMUM WINDS OF ABOUT 60 KT. THIS ESTIMATE WILL BE USED FOR THE INITIAL INTENSITY. LITTLE CHANGE IN STRENGTH IS FORECAST DURING THE NEXT COUPLE OF DAYS AS THE EFFECTS OF INCREASING VERTICAL WIND SHEAR ON THE STORM MAY BE TEMPERED BY INCREASING SSTS. SHEAR IS FORECAST TO INCREASE BY ALL MODELS IN A FEW DAYS...SO THE CYCLONE SHOULD WEAKEN MORE IN THE LONG-TERM. EXTRATROPICAL TRANSITION SHOULD OCCUR IN 4 OR 5 DAYS DUE TO THE EFFECTS OF STRONG MID-LATITUDE WINDS AND RAPIDLY COOLING WATERS. QUIKSCAT DATA HELPED PLACE THE CENTER A LITTLE FARTHER TO THE NORTHWEST THIS MORNING...YIELDING AN UNCERTAIN MOTION ESTIMATE OF 100/3. THE TROPICAL CYCLONE IS EXPECTED TO TURN TOWARD THE SOUTHEAST TODAY AS IT PINWHEELS AROUND A LARGE MIDDLE- TO UPPER-LEVEL LOW TO THE EAST. MODEL GUIDANCE REMAINS IN GOOD AGREEMENT ON AN ARCING PATH TAKING THE SYSTEM FARTHER AWAY FROM NORTH AMERICA. IN TWO TO THREE DAYS... A MID-LATITUDE TROUGH WILL APPROACH BERTHA FROM THE WEST. THERE IS SOME DISAGREEMENT ON HOW QUICKLY THE STORM WILL MOVE OUT TO SEA...BUT MODELS ARE GENERALLY FASTER WITH THE PROGRESSION OF THE STORM. THE OFFICIAL FORECAST IS FAIRLY SIMILAR TO THE PREVIOUS ONE AND IS A LITTLE FASTER. FORECAST POSITIONS AND MAX WINDS INITIAL 16/1500Z 36.6N 60.7W 60 KT 12HR VT 17/0000Z 36.0N 60.1W 60 KT 24HR VT 17/1200Z 35.0N 58.7W 60 KT 36HR VT 18/0000Z 34.7N 56.4W 60 KT 48HR VT 18/1200Z 35.6N 54.0W 60 KT 72HR VT 19/1200Z 40.0N 49.0W 50 KT 96HR VT 20/1200Z 43.5N 44.5W 45 KT...BECOMING EXTRATROPICAL 120HR VT 21/1200Z 47.5N 39.0W 45 KT...EXTRATROPICAL $$ FORECASTER BLAKE |
