000 WTNT44 KNHC 172043 TCDAT4 TROPICAL STORM NADINE DISCUSSION NUMBER 26 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142012 500 PM AST MON SEP 17 2012 A SIGNIFICANT FLARE UP OF DEEP CONVECTION HAS DEVELOPED IN THE NORTHERN SEMICIRCLE DURING THE PAST 6 HOURS...WHICH HAS RESULTED IN A SATELLITE INTENSITY CLASSIFICATION OF T3.0/45 KT FROM BOTH TAFB AND SAB. HOWEVER...CONVECTION HAS CONTINUED TO INCREASE AND DEVELOP CLOSER TO THE LOW-LEVEL CENTER SINCE THAT TIME...SO THE INITIAL INTENSITY HAS ONLY BEEN DECREASED TO 55 KT FOR THIS ADVISORY. UPPER-LEVEL OUTFLOW REMAINS WELL-ESTABLISHED IN ALL QUADRANTS... EXCEPT TO THE SOUTHEAST WHERE IT IS SIGNIFICANTLY RESTRICTED. THE INITIAL MOTION ESTIMATE IS 050/10 KT. THE LATEST 12Z NHC MODEL GUIDANCE IS IN EXCELLENT AGREEMENT ON NADINE GRADUALLY TURNING TOWARD THE NORTH-NORTHEAST AND NORTH WITH A CONTINUED REDUCTION IN FORWARD SPEED OVER THE NEXT 72 HOURS. AS A RESULT...NO SIGNIFICANT CHANGE WAS MADE TO THE PREVIOUS FORECAST TRACK THROUGH DAY 3. HOWEVER...THE MODELS ARE NOW IN BETTER AGREEMENT ON NADINE NOT MOVING AS FAR NORTH AS PREVIOUSLY EXPECTED IN THE LATTER FORECAST PERIODS...WHICH IS EXPECTED TO REDUCE ITS INTERACTION WITH A DEEP-LAYER LOW FORECAST TO DIG SOUTHWARD OUT OF THE HIGH LATITUDES ON DAYS 3-5. AS A RESULT...THE OFFICIAL FORECAST TRACK AT 96- AND 120-HOURS HAS BEEN SHIFTED SIGNIFICANTLY FARTHER TO THE SOUTH AND SOUTHWEST AS COMPARED TO PREVIOUS ADVISORY TRACKS. HOWEVER...THE NHC ADVISORY TRACK REMAINS WELL TO THE NORTHEAST OF THE GFS... ECMWF...AND THE CONSENSUS TRACK MODELS DUE TO THE UNCERTAINTY IS THE EXACT TIMING AND AMOUNT OF INTERACTION EXPECTED TO OCCUR BETWEEN NADINE IN THE AFOREMENTIONED EXTRATROPICAL LOW. NADINE MAY BE ABLE TO FIGHT OFF THE INTRUSIONS OF DRIER AND STABLE AIR...AND COOLER SSTS FOR THE NEXT 48 HOURS OR SO DUE TO ITS LARGE CIRCULATION. BY DAY 3... HOWEVER...SSTS LESS THAN 24C ALONG WITH INCREASING SHEAR AND INTERACTION WITH THE DEEP-LAYER EXTRATROPICAL LOW FORECAST TO DEVELOP NORTH OF THE AZORES SHOULD CAUSE NADINE TO GRADUALLY TRANSITION INTO A STRONG EXTRATROPICAL CYCLONE. BY DAY 5 AS NADINE MOVES SOUTHWARD OVER WARMER SSTS...THE CYCLONE COULD TRANSITION BACK INTO A TROPICAL OR SUBTROPICAL CYCLONE. THE EXACT STATUS OF NADINE AFTER DAY 3...HOWEVER...IS EXPECTED TO HAVE LITTLE IF ANY EFFECT ON ITS INTENSITY. THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY...AND FOLLOWS THE TREND OF THE CONSENSUS MODELS IV15 AND ICON. FORECAST POSITIONS AND MAX WINDS INIT 17/2100Z 33.5N 34.5W 55 KT 65 MPH 12H 18/0600Z 34.3N 33.5W 50 KT 60 MPH 24H 18/1800Z 35.4N 32.7W 50 KT 60 MPH 36H 19/0600Z 36.5N 32.3W 50 KT 60 MPH 48H 19/1800Z 37.1N 31.7W 50 KT 60 MPH 72H 20/1800Z 37.0N 30.1W 50 KT 60 MPH...POST-TROP/EXTRATROP 96H 21/1800Z 35.5N 29.0W 50 KT 60 MPH...POST-TROP/EXTRATROP 120H 22/1800Z 33.0N 30.0W 50 KT 60 MPH...POST-TROP/EXTRATROP $$ FORECASTER STEWART