000
WTNT43 KNHC 202033
TCDAT3
 
TROPICAL STORM CHRIS DISCUSSION NUMBER   5
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
500 PM AST WED JUN 20 2012
 
ALTHOUGH ONLY A FEW BANDING FEATURES ARE SEEN IN INFRARED SATELLITE
PICTURES...VISIBLE IMAGERY SHOWS SEVERAL BANDS OF SHOWERS ROTATING
AROUND THE CENTER.  IN FACT...A RECENT SSMI MICROWAVE IMAGE
REVEALED A RING OF CONVECTION THAT WRAPPED A LITTLE MORE THAN
HALFWAY AROUND THE CENTER.  AN ASCAT PASS THAT ARRIVED SHORTLY
AFTER THE RELEASE OF THE PREVIOUS ADVISORY HAD A COUPLE 40-KT WIND
VECTORS OVER THE SOUTHEASTERN QUADRANT.  GIVEN THE LOW BIAS OF THAT
INSTRUMENT AND THE IMPROVED STRUCTURE IN MICROWAVE IMAGERY SINCE
THAT TIME...THE INITIAL INTENSITY IS INCREASED TO 50 KT.
 
IT IS DOUBTFUL THAT CHRIS WILL STRENGTHEN ANY FURTHER AS A TROPICAL
CYCLONE SINCE IT WILL BE MOVING OVER COLDER WATER WITHIN 12 HOURS. 
THE GLOBAL MODELS CONTINUE TO PREDICT THAT THE CYCLONE WILL
MAINTAIN ITS INTENSITY OR PERHAPS STRENGTHEN A LITTLE AS A
BAROCLINIC SYSTEM ON THURSDAY.  AFTER 36 HOURS...GRADUAL WEAKENING
IS EXPECTED...AND THE SYSTEM IS LIKELY TO MERGE WITH A LARGER
EXTRATROPICAL LOW IN ABOUT 3 DAYS.

CHRIS IS MOVING EASTWARD OR 085 DEGREES AT 18 KT. THE CYCLONE SHOULD
TURN NORTHEASTWARD...THEN NORTHWARD AS AN UPPER-LEVEL TROUGH TO ITS
NORTHWEST CUTS OFF.  THE POST-TROPICAL CYCLONE IS FORECAST TO
ROTATE CYCLONICALLY AROUND THE UPPER-LOW BEFORE THE MERGER TAKES
PLACE.
  
FORECAST POSITIONS AND MAX WINDS
 
INIT  20/2100Z 38.5N  49.0W   50 KT  60 MPH
 12H  21/0600Z 39.4N  45.8W   50 KT  60 MPH
 24H  21/1800Z 41.7N  42.9W   50 KT  60 MPH...POST-TROPICAL
 36H  22/0600Z 44.3N  42.7W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  22/1800Z 44.2N  44.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  23/1800Z 42.5N  43.5W   30 KT  35 MPH...POST-TROP/EXTRATROP
 96H  24/1800Z...DISSIPATED
 
$$
FORECASTER BROWN