[StBernard] TS BILL Discussion 4

[Westley Annis]

000
WTNT43 KNHC 160857
TCDAT3
TROPICAL STORM BILL DISCUSSION NUMBER   4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL032009
500 AM AST SUN AUG 16 2009
 
THE CENTER OF BILL HAS BEEN DIFFICULT TO FIND THIS MORNING...AND A
0419 UTC AMSR-E PASS INDICATED THAT IT HAS EITHER SLOWED DOWN OR
HAS BEEN RE-FORMING CLOSER TO THE DEEP CONVECTION.  DVORAK
T-NUMBERS ARE NOW 3.0 FROM TAFB AND 2.5 FROM SAB...SO THE INITIAL
INTENSITY IS RAISED TO 40 KT.  BILL IS EXPECTED TO GRADUALLY
STRENGTHEN OVER THE NEXT COUPLE OF DAYS...AND THE OFFICIAL FORECAST
FOLLOWS THE UPWARD TREND NOTED IN THE INTENSITY GUIDANCE.  BILL IS
NOW EXPECTED TO REACH MAJOR HURRICANE STATUS BY DAY 5...BUT IT
SHOULD BE NOTED THAT THE 100 KT SHOWN IN THE FORECAST IS STILL
BELOW THE INTENSITY CONSENSUS AND WELL BELOW THE HWRF MODEL.  THIS
IS TO ACCOUNT FOR INCREASED VERTICAL SHEAR THAT MAY DEVELOP BY DAYS
4 AND 5...AS INDICATED IN THE SHIPS GUIDANCE.

THE INITIAL MOTION IS AN UNCERTAIN 270/11.  BILL IS EXPECTED TO
GRADUALLY GAIN LATITUDE AND TURN TO THE WEST-NORTHWEST OVER THE
NEXT FEW DAYS.  THE NEW SUITE OF MODEL GUIDANCE HAS SHIFTED A
LITTLE NORTH OF THE PREVIOUS GUIDANCE ENVELOPE AS MOST OF THE
MODELS APPEAR TO BE SHOWING THE DEVELOPMENT OF A DEEP MID- TO
UPPER-LEVEL TROUGH OVER THE EASTERN UNITED STATES AT THE END OF THE
FORECAST PERIOD.  MOST OF THE MODELS...WITH THE EXCEPTION OF THE
UKMET AS A SOUTHERN OUTLIER...ARE IN REMARKABLY GOOD AGREEMENT
THROUGH DAY 5.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      16/0900Z 11.4N  37.2W    40 KT
 12HR VT     16/1800Z 11.8N  39.3W    45 KT
 24HR VT     17/0600Z 12.5N  41.9W    50 KT
 36HR VT     17/1800Z 13.4N  44.7W    60 KT
 48HR VT     18/0600Z 14.3N  47.5W    70 KT
 72HR VT     19/0600Z 16.5N  53.0W    85 KT
 96HR VT     20/0600Z 19.0N  58.5W    95 KT
120HR VT     21/0600Z 22.0N  64.0W   100 KT
 
$$
FORECASTER BERG