000 WTNT44 KNHC 270249 TCDAT4 TROPICAL STORM NADINE DISCUSSION NUMBER 58 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142012 1100 PM AST WED SEP 26 2012 THE SATELLITE PRESENTATION OF NADINE HAS NOT CHANGED MUCH OVER THE PAST SEVERAL HOURS. DEEP CONVECTION REMAINS LIMITED TO A BAND CURVING AROUND THE EASTERN SEMICIRCLE OF THE TROPICAL CYCLONE. SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB...AS WELL AS DROPSONDE DATA FROM THE NASA GLOBAL HAWK...SUPPORT HOLDING THE INITIAL INTENSITY AT 45 KT. WHILE DRY AIR CONTINUES TO SURROUND NADINE...THE TROPICAL STORM IS MOVING INTO AN AREA OF WARMER SEA SURFACE TEMPERATURES...AND THE VERTICAL WIND SHEAR IS EXPECTED TO REMAIN LIGHT ENOUGH TO ALLOW FOR SOME SLOW STRENGTHENING OVER THE NEXT 36-48 HOURS. AFTER THAT...STRONGER SHEAR AND COOLER SEA SURFACE TEMPERATURES SHOULD TO LEAD TO WEAKENING. THE NHC FORECAST FOLLOWS THE LGEM MODEL AND IS CLOSE TO THE PREVIOUS ADVISORY. NADINE CONTINUES TO MOVE TO THE SOUTHWEST AROUND A DEEP LAYER RIDGE LOCATED OVER THE CENTRAL ATLANTIC...AND THE LONG-TERM MOTION ESTIMATE IS 220/5. THE DYNAMICAL MODEL GUIDANCE REMAINS IN GOOD AGREEMENT THAT NADINE WILL MOVE AROUND THE PERIPHERY OF THE RIDGE FOR THE NEXT SEVERAL DAYS. BY DAY 4...THE RIDGE IS EXPECTED TO MOVE AWAY FROM THE TROPICAL CYCLONE...WHICH SHOULD RESULT IN FAIRLY WEAK ENVIRONMENTAL STEERING CONDITIONS. THE MODEL SPREAD INCREASES SUBSTANTIALLY AT THIS POINT...WITH THE GFS CONTINUING TO SUGGEST A SLOW EASTWARD MOTION WHILE THE ECMWF SHOWS A TURN TOWARD THE WEST OR SOUTHWEST. THE OFFICIAL FORECAST SPLITS THESE TWO SOLUTIONS...AND LIES NEAR THE CONSENSUS MODELS IV15 AND FSSE. THE WIND RADII WERE ADJUSTED BASED ON A 2338 ASCAT PASS. FORECAST POSITIONS AND MAX WINDS INIT 27/0300Z 29.5N 31.4W 45 KT 50 MPH 12H 27/1200Z 28.8N 32.2W 45 KT 50 MPH 24H 28/0000Z 28.6N 33.6W 50 KT 60 MPH 36H 28/1200Z 29.1N 34.8W 50 KT 60 MPH 48H 29/0000Z 30.0N 35.8W 55 KT 65 MPH 72H 30/0000Z 33.0N 36.8W 50 KT 60 MPH 96H 01/0000Z 35.5N 37.5W 50 KT 60 MPH 120H 02/0000Z 36.0N 37.5W 45 KT 50 MPH $$ FORECASTER AVILA/ZELINSKY