Tropical Storm CHRIS

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TROPICAL STORM CHRIS DISCUSSION NUMBER   7
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032012
500 AM AST THU JUN 21 2012
 
CHRIS HAS MAINTAINED AN EYE-LIKE FEATURE SURROUNDED BY A RING OF
CONVECTION WITH CLOUD TOP TEMPERATURES OF -50C TO -60C DURING THE
PAST FEW HOURS.  SUBJECTIVE AND OBJECTIVE DVORAK T-NUMBERS ARE
ESSENTIALLY UNCHANGED SINCE THE LAST ADVISORY AND DO NOT SUPPORT A
HIGHER INTENSITY...SO THE INITIAL INTENSITY IS KEPT AT 50 KT. EVEN
IF CHRIS IS STRONGER THAN ESTIMATED...THE PASSAGE OF THE CYCLONE
OVER SUB-22C SEA SURFACE TEMPERATURES COULD BE INHIBITING AN
EFFICIENT CONVECTIVE TRANSPORT OF THE STRONGEST WINDS TO THE
OCEAN SURFACE.
 
THE INITIAL MOTION IS 065/17...WHICH IS A BIT SLOWER AND TO THE LEFT
OF THE PREVIOUS ESTIMATE.  CHRIS IS EXPECTED TO TURN NORTH-
NORTHEASTWARD AND THEN NORTHWARD AS IT DECELERATES AND DUMBBELLS
CYCLONICALLY AROUND A LARGE MID- TO UPPER-LEVEL LOW FORECAST TO CUT
OFF SOUTHEAST OF THE CANADIAN MARITIME PROVINCES DURING THE NEXT
24-36 HOURS. MODEL GUIDANCE GENERALLY SHOWS CHRIS BEING ABSORBED BY
THIS WEATHER FEATURE IN 36-48 HOURS...WITH THE NEW ENTITY
COMPLETING A CYCLONIC LOOP AND THEN MOVING EASTWARD TO EAST-
NORTHEASTWARD OVER THE FAR NORTH ATLANTIC. GLOBAL MODELS ARE IN
GOOD AGREEMENT WITH REGARD TO THIS SCENARIO...AND THE TRACK
FORECAST IS BASICALLY AN UPDATE OF THE PREVIOUS ONE.
 
DESPITE THE FACT THAT CHRIS IS MOVING OVER RATHER COOL WATERS...
A 0505 UTC AMSU PASSES STILL SHOWED THE PRESENCE OF A WELL-DEFINED
MODERATE TO DEEP WARM CORE IN ASSOCIATION WITH THE CYCLONE.
ALTHOUGH CHRIS IS EXPECTED TO MAINTAIN WARM-CORE CHARACTERISTICS
DURING THE NEXT 24 HOURS OR SO...IT COULD LOSE ITS DEEP CONVECTION
WHILE MOVING OVER EVEN COOLER WATERS AND BE DECLARED POST-TROPICAL. 
SHOULD IT MAINTAIN DEEP CONVECTION LONGER...EITHER ITS INTERACTION
WITH A LOW-LEVEL BAROCLINIC ZONE TO THE NORTH AND/OR ITS
INTERACTION WITH THE CUT-OFF LOW TO ITS WEST SHOULD RESULT IN
EXTRATROPICAL TRANSITION IN ABOUT 36 HOURS.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  21/0900Z 39.9N  44.8W   50 KT  60 MPH
 12H  21/1800Z 41.6N  43.1W   50 KT  60 MPH
 24H  22/0600Z 43.6N  43.0W   50 KT  60 MPH...POST-TROPICAL
 36H  22/1800Z 44.3N  44.8W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  23/0600Z 43.0N  46.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  24/0600Z...ABSORBED BY ANOTHER EXTRATROPICAL LOW
 
$$
FORECASTER KIMBERLAIN
 
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