[Tropical] Tropical Cyclone Discussion

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WTNT42 KNHC 201440
TCDAT2

TROPICAL STORM BRET DISCUSSION NUMBER  12
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL022011
1100 AM EDT WED JUL 20 2011

WHILE THE OVERALL CLOUD PATTERN REMAINS THAT OF A SHEARED
CYCLONE...CONVECTION HAS FLARED UP NEAR AND TO THE SOUTH OF THE
CENTER OF BRET THIS MORNING.  ANALYSES FROM CIMSS AT THE UNIVERSITY
OF WISCONSIN SUGGEST ABOUT 20 KT OF NORTHERLY VERTICAL WIND SHEAR
OVER THE SYSTEM...WHICH IS A LITTLE LESS THEN EARLIER.  THE INITIAL
INTENSITY REMAINS 45 KT BASED ON THE CONVECTIVE TRENDS AND DATA
FROM THE PREVIOUS AIRCRAFT MISSION.  ANOTHER AIRCRAFT WILL
INVESTIGATE BRET THIS AFTERNOON.

THE INITIAL MOTION IS 045/8.  BRET IS EMBEDDED IN LOW/MID-LEVEL
SOUTHWESTERLY FLOW ON THE NORTH SIDE OF THE SUBTROPICAL RIDGE...AND
THIS PATTERN SHOULD PRODUCE A NORTHEASTWARD MOTION UNTIL THE SYSTEM
DISSIPATES.  THE NEW FORECAST TRACK IS AGAIN AN UPDATE OF THE
PREVIOUS FORECAST.

WHILE THE SHEAR HAS DECREASED SLIGHTLY...THE LARGE-SCALE MODELS
FORECAST IT TO INCREASE AGAIN AFTER ABOUT 12 HR.  IN ADDITION...
WATER VAPOR IMAGERY SHOWS A LARGE AREA OF UPPER-LEVEL DRY AND
SUBSIDENCE OVER THE MID-ATLANTIC STATES MOVING SOUTHEASTWARD TOWARD
BRET.  THIS COMBINATION SHOULD WEAKEN THE STORM AND LEAD TO ITS
DISSIPATION IN 48-72 HR.


FORECAST POSITIONS AND MAX WINDS

INIT  20/1500Z 31.8N  73.7W   45 KT  50 MPH
 12H  21/0000Z 32.5N  72.7W   45 KT  50 MPH
 24H  21/1200Z 33.8N  71.1W   40 KT  45 MPH
 36H  22/0000Z 35.4N  69.2W   35 KT  40 MPH
 48H  22/1200Z 37.0N  66.5W   30 KT  35 MPH
 72H  23/1200Z...DISSIPATED

$$
FORECASTER BEVEN


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