Tropical Storm CRISTOBAL

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TROPICAL STORM CRISTOBAL DISCUSSION NUMBER   4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL032008
500 PM EDT SAT JUL 19 2008
 
THE AIR FORCE HURRICANE HUNTER HAS FOUND MAXIMUM FLIGHT LEVEL WINDS
OF 58 KT AT 2500 FT...CORRESPONDING TO ABOUT 45 KT AT THE SURFACE.
HOWEVER...SFMR DATA AT THAT SAME LOCATION SHOWED ONLY 35 KT AND
CONVECTION HAS BEEN WEAKENING NEAR THE CENTER. THE INITIAL
INTENSITY IS A COMPROMISE BETWEEN THESE VALUES AND IS SET TO 40 KT.
FURTHER INTENSIFICATION IS POSSIBLE AS THE SYSTEM MOVES OVER WARM
GULF STREAM WATERS AND EXPERIENCES LIGHT SHEAR. THE OFFICIAL
FORECAST IS INCREASED FROM THE PREVIOUS ONE AND IS CLOSE TO A
SHIFOR/SHIPS CONSENSUS. STRANGELY...THE GFDL/HWRF STILL REFUSE TO
INTENSIFY THIS SYSTEM.
 
THE INITIAL MOTION ESTIMATE IS 050/6.  THERE IS NO CHANGE TO THE
PREVIOUS SYNOPTIC REASONING. A WEAK MID-TROPOSPHERIC RIDGE TO THE
SOUTHEAST OF THE STORM SHOULD CONTINUE TO MOVE THE SYSTEM AT ABOUT
THE SAME HEADING AND SPEED DURING THE NEXT DAY OR SO. MODEL
GUIDANCE REMAINS IN GOOD AGREEMENT ON TAKING THE SYSTEM NEARLY
PARALLEL TO THE NORTH CAROLINA COAST DURING THE NEXT DAY OR SO.
THEREAFTER...THE DEPRESSION WILL MOVE FASTER TO THE NORTHEAST
BETWEEN A BUILDING RIDGE TO THE EAST AND A DEEPENING MIDDLE-
LATITUDE TROUGH OVER EASTERN NORTH AMERICA. THE MODELS DO DIVERGE A
LITTLE ON WHETHER THE STORM WILL BE TURN A LITTLE MORE TO THE LEFT
IN RESPONSE TO THE TROUGH OR STAY MORE SEPARATE FROM THAT FEATURE.
THE OFFICIAL FORECAST IS A TAD FASTER AND A LITTLE LEFT OF THE
PREVIOUS ONE AFTER 36 HR...NEAR THE CENTER OF THE GUIDANCE
ENVELOPE.
 
  
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      19/2100Z 33.0N  77.9W    40 KT
 12HR VT     20/0600Z 33.7N  77.0W    45 KT
 24HR VT     20/1800Z 34.7N  75.6W    50 KT
 36HR VT     21/0600Z 35.9N  73.9W    55 KT
 48HR VT     21/1800Z 38.0N  71.3W    55 KT
 72HR VT     22/1800Z 43.5N  64.0W    45 KT...EXTRATROPICAL
 96HR VT     23/1800Z...ABSORBED
 
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FORECASTER BLAKE/KNABB
 
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