Tropical Storm CRISTOBAL

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TROPICAL STORM CRISTOBAL DISCUSSION NUMBER  11
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL032008
1100 AM EDT MON JUL 21 2008

SATELLITE IMAGES INDICATE THAT CONVECTION REMAINS QUITE STRONG IN
THE SOUTHERN PORTION OF THE STORM.  ON THE LAST PASS THROUGH THE
STORM...THE AIR FORCE PLANE FOUND A FALLING PRESSURE AND SOME
EVIDENCE OF A CENTER REFORMATION TO THE SOUTH. A QUIKSCAT PASS FROM
THIS MORNING SUGGESTS THE MAXIMUM WINDS WERE 50-55 KT...WHICH ISN'T
TOO FAR FROM THE SFMR DATA COLLECTED BY THE PLANE.  THE INITIAL
INTENSITY IS INCREASED TO 55 KT FOR THIS ADVISORY.  SOME
INTENSIFICATION IS POSSIBLE WHILE THE CENTER MOVES ACROSS THE GULF
STREAM AND THE SHEAR REMAINS LOW DURING THE NEXT 24 HR OR SO. 
THEREAFTER...CRISTOBAL IS FORECAST TO MOVE NORTH OF THE GULF STREAM
AND INTO A STRONGER SHEARING ENVIRONMENT...WHICH SHOULD BEGIN THE
WEAKENING PROCESS.  THE OFFICIAL FORECAST IS IN GOOD AGREEMENT WITH
THE SHIPS/LGEM MODELS WHICH SHOW THIS SYSTEM STAYING JUST BELOW
HURRICANE STRENGTH.

THE INITIAL MOTION IS A LITTLE UNCERTAIN DUE TO TO CENTER
REFORMATION BUT IS ESTIMATED AT 055/11.  A TRACK TO THE NORTHEAST
WITH INCREASING FORWARD SPEED IS LIKELY IN RESPONSE TO AN
APPROACHING MID-TROPOSPHERIC TROUGH.  THIS SYSTEM SHOULD TURN MORE
TO THE EAST WITH TIME AS IT MOVES INTO MORE WESTERLY FLOW.  THE
BIGGEST CHANGE FROM THE LAST ADVISORY IS THAT MORE MODELS SUGGEST
THAT THE STORM WON'T BE FULLY ABSORBED BY A TROUGH OVER NORTH
AMERICA AND INSTEAD ROTATE AROUND THE SOUTHERN END OF THE TROUGH.  
THE OFFICIAL FORECAST IS SHIFTED SOUTHWARD AT THE END OF THE PERIOD
AND IS EXTENDED TO 96 HR IN LINE WITH THE GUIDANCE.  
  
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      21/1500Z 36.6N  72.6W    55 KT
 12HR VT     22/0000Z 37.9N  70.6W    60 KT
 24HR VT     22/1200Z 40.5N  67.5W    60 KT
 36HR VT     23/0000Z 43.3N  63.5W    55 KT...BECOMING EXTRATROPICAL
 48HR VT     23/1200Z 45.0N  59.0W    45 KT...EXTRATROPICAL
 72HR VT     24/1200Z 45.0N  47.0W    40 KT...EXTRATROPICAL
 96HR VT     25/1200Z 41.0N  40.0W    35 KT...EXTRATROPICAL
120HR VT     26/1200Z...DISSIPATED
 
$$
FORECASTER BLAKE
 
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