Tropical Storm CRISTOBAL

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TROPICAL STORM CRISTOBAL DISCUSSION NUMBER  13
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL032008
1100 PM EDT MON JUL 21 2008
 
CRISTOBAL APPEARS TO BE SUCCUMBING TO THE COOLER SSTS AS DEEP
CONVECTION HAS SIGNIFICANTLY DECREASED DURING THE LAST 6 HOURS. THE
INITIAL INTENSITY IS LOWERED TO 50 KT BASED ON A RECENT QUIKSCAT
PASS.  GIVEN THE EXTREMELY COLD SSTS THAT CRISTOBAL WILL ENCOUNTER
ALONG THE FORECAST TRACK...FURTHER WEAKENING APPEARS LIKELY.  THE
FLORIDA STATE UNIVERSITY CYCLONE PHASE SPACE DIAGRAM INDICATES THE
SYSTEM WILL BE EXTRATROPICAL IN ABOUT 36 HOURS.  HOWEVER...IF THE
PRESENT TREND IN CONVECTION CONTINUES...CRISTOBAL COULD BECOME A
REMNANT LOW PRIOR TO ITS TRANSITION TO AN EXTRATROPICAL CYCLONE.  
REGARDLESS...SIGNIFICANT RESTRENGTHENING DOES NOT APPEAR LIKELY AT
THIS TIME DUE TO LACK OF BAROCLINIC FORCING. 
 
CRISTOBAL CONTINUES TO ACCELERATE EAST-NORTHEASTWARD WITHIN THE
DEEP-LAYER SOUTHWESTERLY FLOW AHEAD OF A TROUGH OVER THE EASTERN
UNITED STATES...AND THE INITIAL MOTION ESTIMATE IS NOW 060/14.
TRACK MODELS ARE IN GOOD AGREEMENT ON A GRADUAL TURN EASTWARD AT
DAY TWO AS CRISTOBAL MOVES AROUND THE NORTH SIDE A RIDGE OVER THE
CENTRAL ATLANTIC.  THEREAFTER...GUIDANCE DIVERGES DUE TO DIFFERING
FORECASTS OF A TROUGH...AND ITS ASSOCIATED SURFACE FRONT...WHICH
AMPLIFIES SOUTHWARD OVER THE NORTHEAST ATLANTIC.  CONSIDERING THE
UNCERTAINTY...THE OFFICIAL FORECAST LIES NEAR THE CENTER OF THE
DYNAMICAL MODEL CONSENSUS AT DAYS 3 AND 4. 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      22/0300Z 37.7N  69.8W    50 KT
 12HR VT     22/1200Z 39.8N  67.1W    45 KT
 24HR VT     23/0000Z 42.5N  62.7W    40 KT
 36HR VT     23/1200Z 44.0N  57.9W    35 KT...EXTRATROPICAL
 48HR VT     24/0000Z 44.0N  52.8W    35 KT...EXTRATROPICAL
 72HR VT     25/0000Z 41.0N  44.5W    30 KT...EXTRATROPICAL
 96HR VT     26/0000Z 37.5N  41.0W    25 KT...EXTRATROPICAL
120HR VT     27/0000Z...DISSIPATED
 
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FORECASTER RHOME
 
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