000 WTNT44 KNHC 270903 TCDAT4 TROPICAL STORM NADINE DISCUSSION NUMBER 59 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142012 500 AM AST THU SEP 27 2012 SATELLITE IMAGES INDICATE THAT NADINE HAS BECOME BETTER ORGANIZED OVER THE PAST SEVERAL HOURS WITH INCREASED CONVECTION IN THE NORTHERN AND EASTERN SEMICIRCLES. DROPSONDE DATA FROM THE NASA GLOBAL HAWK SHOWED A LAYER OF 65-70 KT WINDS BETWEEN 850 AND 950 MB NORTH OF THE CENTER. THESE DATA...IN CONJUNCTION WITH THE IMPROVED SATELLITE PRESENTATION...SUGGEST THE MAXIMUM WINDS ARE A BIT HIGHER...AND THE INITIAL WIND SPEED IS SET TO 50 KT. FURTHER STRENGTHENING IS POSSIBLE OVER THE NEXT DAY OR TWO...ALTHOUGH ONLY THE HWRF MAKES NADINE A HURRICANE AGAIN. THE OFFICIAL FORECAST IS ONLY A LITTLE HIGHER THAN THE PREVIOUS ONE...A BIT ABOVE THE MODEL CONSENSUS...ALTHOUGH GIVEN THE RECENT SATELLITE TRENDS THIS FORECAST SEEMS CONSERVATIVE. SOME WEAKENING COULD BEGIN IN A FEW DAYS WHEN NADINE MOVES OVER COOLER WATERS. THE INITIAL MOTION ESTIMATE IS 220/5. THE STORM SHOULD TURN WESTWARD LATER TODAY AND THEN NORTHWESTWARD ON FRIDAY AS IT REMAINS STEERED BY A RIDGE OVER THE NORTHEASTERN ATLANTIC OCEAN. WHILE THE MODEL GUIDANCE IS IN PRETTY GOOD AGREEMENT DURING THE FIRST THREE DAYS...THE SPREAD INCREASES GREATLY BY DAY 5. THIS SPREAD IS DUE TO DIFFERENCES IN HOW NADINE INTERACTS WITH A DEVELOPING TROUGH OVER THE CENTRAL ATLANTIC. THE GFS/GFS ENSEMBLE MEAN SHOW NADINE RECURVING AHEAD OF THIS TROUGH...WHILE THE ECMWF/UKMET MODELS INSTEAD SHOW NADINE MOVING SOUTHWARD BY THE END OF THE FORECAST AS IT BECOMES ENTANGLED BY THE TROUGH. THE NEW NHC FORECAST SPLITS THE DIFFERENCES AND SHOWS LITTLE MOTION AT DAY 5...ALTHOUGH I FEAR THAT NADINE WILL FIND A WAY TO LINGER EVEN LONGER OVER THE NORTHEASTERN ATLANTIC. FORECAST POSITIONS AND MAX WINDS INIT 27/0900Z 28.9N 31.5W 50 KT 60 MPH 12H 27/1800Z 28.5N 32.4W 50 KT 60 MPH 24H 28/0600Z 28.6N 33.6W 50 KT 60 MPH 36H 28/1800Z 29.4N 34.6W 55 KT 65 MPH 48H 29/0600Z 30.7N 35.4W 55 KT 65 MPH 72H 30/0600Z 33.5N 36.3W 50 KT 60 MPH 96H 01/0600Z 35.4N 37.0W 50 KT 60 MPH 120H 02/0600Z 35.5N 37.0W 45 KT 50 MPH $$ FORECASTER BLAKE