Tropical Storm CRISTOBAL

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TROPICAL STORM CRISTOBAL DISCUSSION NUMBER  12
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL032008
500 PM EDT MON JUL 21 2008

A LARGE BALL OF CONVECTION REMAINS ON THE SOUTH SIDE OF THE TROPICAL
CYCLONE.  MICROWAVE AND CONVENTIONAL SATELLITE IMAGERY SUGGESTS THE
CENTER IS IN THE NORTHERN PORTION OF THE DEEP CONVECTION.  THERE
HAS BEEN LITTLE CHANGE TO INTENSITY ESTIMATES...SO THE INITIAL
INTENSITY WILL REMAIN 55 KT.  IT IS POSSIBLE THAT CRISTOBAL COULD
BE CLOSE TO HURRICANE STRENGTH BEFORE MOVING OVER THE COOLER WATERS
NORTH OF THE GULF STREAM TOMORROW.  THE INTENSITY FORECAST IS VERY
SIMILAR TO THE PREVIOUS AND IS CLOSE TO A CONSENSUS OF THE
STATISTICAL MODELS.  PHASE SPACE DIAGRAMS FROM FLORIDA STATE
SUGGEST THAT A RAPID EXTRATROPICAL TRANSITION SHOULD START TOMORROW
AND BE COMPLETED BY WEDNESDAY.  

THE INITIAL MOTION ESTIMATE IS 055/12...A LITTLE FASTER THAN
EARLIER. GLOBAL MODELS ARE IN EXCELLENT AGREEMENT ON AN
ACCELERATING NORTHEASTWARD TRACK DURING THE NEXT DAY OR SO.
THEREAFTER...THE STORM IS NOW FORECAST TO AVOID ANY TROUGHING OVER
NORTH AMERICA AND INSTEAD RIDE ALONG THE WESTERLIES TO THE NORTH OF
A SUBTROPICAL RIDGE OVER THE CENTRAL ATLANTIC OCEAN. IN A COUPLE
DAYS...A NEW TROUGH IS FORECAST TO AMPLIFY TO THE EAST OF THE
STORM...WHICH SHOULD STEER THE CYCLONE MORE TO THE SOUTHEAST. THE
OFFICIAL FORECAST IS SHIFTED TO THE SOUTH AND IS NOT TOO FAR FROM
THE GFS BY 96 HOURS. MOST OF THE MODELS SUGGEST NO BAROCLINIC
REINTENSIFICATION WILL OCCUR AND INSTEAD CRISTOBAL MAY DISSIPATE
OVER THE COLD NORTH ATLANTIC WATERS IN ABOUT 120 HOURS.
  
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      21/2100Z 37.1N  71.4W    55 KT
 12HR VT     22/0600Z 38.9N  68.7W    60 KT
 24HR VT     22/1800Z 41.7N  64.7W    60 KT
 36HR VT     23/0600Z 44.0N  60.0W    50 KT...EXTRATROPICAL
 48HR VT     23/1800Z 45.0N  55.0W    40 KT...EXTRATROPICAL
 72HR VT     24/1800Z 42.5N  45.0W    35 KT...EXTRATROPICAL
 96HR VT     25/1800Z 38.5N  40.5W    25 KT...EXTRATROPICAL
120HR VT     26/1800Z...DISSIPATED
 
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FORECASTER BLAKE
 
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