Tropical Storm NADINE
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TROPICAL STORM NADINE DISCUSSION NUMBER 13
NWS NATIONAL HURRICANE CENTER MIAMI FL AL142012
ISSUED BY THE HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
1100 AM AST FRI SEP 14 2012
NADINE CONTINUES TO SHOW LITTLE CHANGE IN ORGANIZATION ON SATELLITE
IMAGERY. THE LOW CLOUD LINES ON VISIBLE IMAGERY SUGGEST THAT THE
CENTER IS DISPLACED A LITTLE TO THE SOUTHWESTERN PART OF THE
CENTRAL DENSE OVERCAST. DVORAK INTENSITY ESTIMATES FROM TAFB AND
SAB REMAIN AT 65 AND 55 KT...RESPECTIVELY...SO THE CURRENT
INTENSITY ESTIMATE IS KEPT AT 60 KT. THE INTENSITY FORECAST FOR
NADINE HAS BEEN A BIT CHALLENGING AS THE SYSTEM HAS REMAINED IN A
MARGINAL ATMOSPHERIC ENVIRONMENT OVER THE PAST FEW DAYS. A LARGE
UPPER-LEVEL TROUGH IN THE VICINITY OF 65-70W LONGITUDE HAS BEEN
PRODUCING SOUTHWESTERLY SHEAR OVER NADINE. AS THE TROPICAL CYCLONE
MOVES NORTHEASTWARD TO EASTWARD OVER THE NEXT FEW DAYS...THE
INFLUENCE OF THIS TROUGH WILL DIMINISH. THE GLOBAL MODELS THEN
SHOW AN UPPER-LEVEL RIDGE MOVING MORE OR LESS IN TANDEM WITH THE
TROPICAL CYCLONE DURING THE FORECAST PERIOD. THESE MODELS INDICATE
THAT SOME DECREASE IN SHEAR IS LIKELY IN A FEW DAYS...WHICH WOULD
GIVE NADINE THE OPPORTUNITY FOR SOME STRENGTHENING. THIS IS
REFLECTED IN THE OFFICIAL FORECAST...WHICH IS ALSO IN GOOD
AGREEMENT A CONSENSUS THAT INCLUDES GUIDANCE FROM THE HURRICANE
FORECAST IMPROVEMENT PROGRAM...HFIP...MODELS.
NADINE HAS MADE ITS EXPECTED TURN TO THE NORTH AND THE INITIAL
MOTION IS NOW 360/14. THE TROPICAL CYCLONE SHOULD CONTINUE TO MOVE
AROUND THE PERIPHERY OF A SUBTROPICAL RIDGE AND TURN EASTWARD IN
THE FLOW ON THE NORTH SIDE OF THE RIDGE. BY THE END OF THE FORECAST
PERIOD...NADINE IS EXPECTED TO TURN TOWARD THE LEFT AS IT INTERACTS
WITH A CYCLONIC CIRCULATION NEAR THE AZORES. THE GUIDANCE ENVELOPE
IS BRACKETED BY THE ECMWF TO THE RIGHT/SOUTH AND THE GFDL TO THE
LEFT/NORTH. THE OFFICIAL TRACK FORECAST IS CLOSE TO THE PREVIOUS
ONE...AND LIES BETWEEN THE GFS AND THE MULTI-MODEL CONSENSUS TVCN.
FORECAST POSITIONS AND MAX WINDS
INIT 14/1500Z 28.0N 53.5W 60 KT 70 MPH
12H 15/0000Z 29.6N 53.1W 60 KT 70 MPH
24H 15/1200Z 31.0N 51.5W 60 KT 70 MPH
36H 16/0000Z 31.5N 49.4W 60 KT 70 MPH
48H 16/1200Z 31.8N 46.8W 65 KT 75 MPH
72H 17/1200Z 32.5N 40.5W 65 KT 75 MPH
96H 18/1200Z 34.5N 35.0W 65 KT 75 MPH
120H 19/1200Z 36.5N 30.5W 60 KT 70 MPH
$$
FORECASTER PASCH/HAMRICK/FRACASSO
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