857 
 WTNT42 KNHC 161431
 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