000
WTNT43 KNHC 201441
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   4
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
1100 AM AST WED JUN 20 2012
 
THE SATELLITE APPEARANCE OF CHRIS HAS IMPROVED SINCE YESTERDAY.
THE TROPICAL CYCLONE HAS BECOME MORE SYMMETRIC WITH SEVERAL BANDS
OF SHOWERS WRAPPING AROUND THE CENTER.  THE LATEST DVORAK INTENSITY
ESTIMATE FROM TAFB AND RECENT UW/CIMSS ADVANCED DVORAK TECHNIQUE
T-NUMBERS SUPPORT AN INITIAL WIND SPEED OF 45 KT.  ENVIRONMENTAL
CONDITIONS ARE EXPECTED TO REMAIN MARGINALLY CONDUCIVE FOR SOME
SLIGHT STRENGTHENING DURING THE NEXT 12-18 HOURS.  AFTER THAT
TIME...CHRIS WILL BE INTERACTING WITH A FRONTAL BOUNDARY AND MOVING
OVER MUCH COLDER WATERS. HOWEVER...THE GLOBAL MODELS INDICATE THAT
THE CYCLONE WILL INITIALLY MAINTAIN ITS STRENGTH AS AN
EXTRATROPICAL CYCLONE...BEFORE WEAKENING IN 2-3 DAYS.  RECENT RUNS
OF THE GLOBAL MODELS SUGGEST THAT THE POST-TROPICAL LOW COULD
REMAIN THE DOMINANT SYSTEM AND NOT BE THE ONE ABSORBED BY ANOTHER
EXTRATROPICAL LOW.  FOR NOW THE NHC FORECAST WILL CONTINUE TO CALL
FOR POST-TROPICAL CHRIS TO BE ABSORBED...BUT CHANGES TO THIS
SCENARIO MAY BE REQUIRED IF MODEL TRENDS CONTINUE.
 
CHRIS APPEARS TO HAVE TURNED EASTWARD WITH AN INITIAL MOTION OF
090/19 KT.  THE OFFICIAL FORECAST REASONING REMAINS UNCHANGED FROM
THE PREVIOUS ADVISORY.  CHRIS IS EXPECTED TO TURN TOWARD THE
NORTHEAST...THEN NORTHWARD WITHIN THE NEXT 24-36 HOURS AS A CLOSED
LOW FORMS OVER THE NORTH ATLANTIC. LATER IN THE PERIOD...THE
POST-TROPICAL CYCLONE IS FORECAST TO ROTATE CYCLONICALLY AROUND THE
UPPER-LEVEL LOW.  THE NHC FORECAST IS CLOSE TO THE GFS...
ECMWF...AND ON THE POST-TROPICAL PORTION OF THE TRACK PROVIDED BY
THE NOAA OCEAN PREDICTION CENTER.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  20/1500Z 38.1N  51.3W   45 KT  50 MPH
 12H  21/0000Z 38.6N  47.6W   50 KT  60 MPH
 24H  21/1200Z 40.5N  43.3W   45 KT  50 MPH
 36H  22/0000Z 43.6N  41.8W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  22/1200Z 45.0N  43.2W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  23/1200Z 43.0N  45.5W   30 KT  35 MPH...POST-TROP/EXTRATROP
 96H  24/1200Z...ABSORBED BY A LARGER EXTRATROPICAL LOW
 
$$
FORECASTER BROWN