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Tropical Depression TWELVE (Text)

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TROPICAL DEPRESSION TWELVE DISCUSSION NUMBER   2
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL122011
1100 AM AST MON AUG 29 2011
 
SATELLITE IMAGES INDICATE THAT THE CLOUD PATTERN OF THE DEPRESSION
HAS CHANGED LITTLE IN ORGANIZATION FROM EARLIER THIS MORNING. 
THERE ARE SOME BROKEN BANDS OVER THE WESTERN AND SOUTHERN PORTION
OF THE CIRCULATION...AND THE CENTER OF THE CYCLONE IS NEAR THE
NORTHEASTERN EDGE OF THE MAIN AREA OF DEEP CONVECTION.  DVORAK
INTENSITY ESTIMATES REMAIN AT 25 AND 30 KT FROM SAB AND TAFB...
RESPECTIVELY...AND THE INTIAL INTENSITY IS KEPT AT 30 KT.  CURRENTLY
THERE IS MODERATE TO STRONG EAST-NORTHEASTERLY SHEAR OVER THE
SYSTEM AS EVIDENCED BY ITS APPEARANCE AND GLOBAL MODEL OUTPUT.  THE
SHIPS GUIDANCE INDICATES THAT THIS SHEAR WILL SOON LESSEN...WHICH
SHOULD ALLOW THE DEPRESSION TO STRENGTHEN.  THE OFFICIAL INTENSITY
FORECAST IS A LITTLE BELOW THE LATEST LGEM GUIDANCE.

THE INITIAL MOTION IS WESTWARD OR 275/13.  THERE IS A MID-LEVEL
RIDGE TO THE NORTH OF THE DEPRESSION AT THIS TIME...BUT  A MID- TO
UPPER-LEVEL LOW IS FORECAST TO CREATE A WEAKNESS IN THE RIDGE NEAR
40-50W OVER THE NEXT COUPLE OF DAYS.  THIS FEATURE SHOULD CAUSE THE
TROPICAL CYCLONE TO TURN TOWARD THE WEST-NORTHWEST WITHIN THE NEXT
DAY OR SO.  LATER IN THE FORECAST PERIOD...GLOBAL MODELS SHOW THE
WEAKNESS IN THE RIDGE SHIFTING WESTWARD AND THIS SHOULD PREVENT THE
CYCLONE FROM MOVING SIGNIFICANTLY POLEWARD DURING THE FORECAST
PERIOD.  THE OFFICIAL TRACK FORECAST IS SIMILAR TO THE PREVIOUS ONE
AND ON THE SOUTHERN SIDE OF THE GUIDANCE ENVELOPE.   
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  29/1500Z  9.8N  27.5W   30 KT  35 MPH
 12H  30/0000Z 10.3N  29.2W   35 KT  40 MPH
 24H  30/1200Z 11.2N  31.4W   45 KT  50 MPH
 36H  31/0000Z 12.3N  34.1W   50 KT  60 MPH
 48H  31/1200Z 13.4N  37.2W   55 KT  65 MPH
 72H  01/1200Z 15.0N  43.0W   70 KT  80 MPH
 96H  02/1200Z 16.5N  48.5W   80 KT  90 MPH
120H  03/1200Z 18.5N  53.0W   90 KT 105 MPH
 
$$
FORECASTER PASCH
 
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