Tropical Storm CHRIS

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TROPICAL STORM CHRIS DISCUSSION NUMBER   6
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
1100 PM AST WED JUN 20 2012
 
CHRIS HAS HAD WHAT COULD BE CONSIDERED AN EYE FOR THE PAST SEVERAL
HOURS.  HOWEVER...SUBJECTIVE AND OBJECTIVE SATELLITE INTENSITY
ESTIMATES DO NOT SUPPORT ANY SIGNIFICANT CHANGE IN STRENGTH.  THE
MAXIMUM WINDS ARE THEREFORE BEING KEPT AT 50 KT.  EVEN IF CHRIS IS
A LITTLE STRONGER...THE CYCLONE IS NOW MOVING OVER SEA SURFACE
TEMPERATURES LESS THAN 22C...AND THE MARINE BOUNDARY LAYER COULD BE
TOO STABLE TO ALLOW STRONGER WINDS TO BE MIXED TO THE OCEAN
SURFACE.

THE INITIAL MOTION IS 075 DEGREES AT 19 KT...AND CHRIS WILL LIKELY
BEGIN TO DECELERATE AND LOOP COUNTERCLOCKWISE WHILE INTERACTING
WITH A DEVELOPING UPPER LOW TO ITS NORTH.  THERE IS VERY LITTLE
DISPARITY BETWEEN THE TRACK MODELS OVER THE NEXT COUPLE OF DAYS. 
THE GLOBAL MODELS ALSO SEEM TO AGREE THAT CHRIS WILL BE ABSORBED BY
OR MERGE WITH ANOTHER EXTRATROPICAL LOW BY 72 HOURS.

THE POST-TROPICAL TRANSITION IS THE TRICKIEST PART OF THE FORECAST. 
THE FSU PHASE SPACE DIAGRAMS STILL ARGUE THAT CHRIS WILL DEVELOP A
DEEPER WARM CORE OVER THE NEXT FEW DAYS.  HOWEVER...THE GFS FIELDS
SHOW CHRIS BEGINNING TO INTERACT WITH A FRONTAL BOUNDARY TO ITS
NORTH IN ABOUT 24 HOURS...ENDING UP ON THE COLD SIDE OF THE
BOUNDARY BY 48 HOURS.  CHRIS COULD BECOME POST-TROPICAL SOMETIME
OVER THE NEXT 24 HOURS IF IT LOSES ITS DEEP CONVECTION...AND IT
SHOULD BE INVOLVED WITH THE FRONT ENOUGH TO BE EXTRATROPICAL BY 36
HOURS.

THE INTENSITY IS EXPECTED TO CHANGE LITTLE OVER THE NEXT 24 HOURS. 
GRADUAL WEAKENING SHOULD START WHEN CHRIS BECOMES EXTRATROPICAL.


FORECAST POSITIONS AND MAX WINDS
 
INIT  21/0300Z 38.9N  46.4W   50 KT  60 MPH
 12H  21/1200Z 40.3N  43.6W   50 KT  60 MPH
 24H  22/0000Z 43.0N  42.1W   50 KT  60 MPH...POST-TROPICAL
 36H  22/1200Z 44.5N  43.2W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  23/0000Z 43.8N  45.4W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  24/0000Z...ABSORBED BY ANOTHER EXTRATROPICAL LOW
 
$$
FORECASTER BERG
 
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