000
WTNT44 KNHC 200251
TCDAT4
 
TROPICAL STORM NADINE DISCUSSION NUMBER  35
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142012
1100 PM AST WED SEP 19 2012
 
NADINE CONTINUES TO BE A RESILIENT TROPICAL CYCLONE...AS AN AREA OF
CONVECTION HAS RECENTLY DEVELOPED JUST TO THE NORTHWEST OF THE
CENTER.  A RECENT ASCAT PASS INDICATED MAXIMUM WINDS OF AROUND 45
KT...SO THE INITIAL INTENSITY REMAINS AT THE VALUE.  ENVIRONMENTAL
CONDITIONS ARE NOT FORECAST TO CHANGE VERY MUCH DURING THE NEXT
COUPLE OF DAYS...WITH NADINE STAYING OVER MARGINAL SSTS AND IN
MODERATE SOUTHWESTERLY SHEAR.  THE OFFICIAL FORECAST CALLS FOR
LITTLE CHANGE IN STRENGTH THROUGHOUT THE FORECAST PERIOD...AS THE
SUGGESTED BY GLOBAL MODELS.  WITH THE RECENT INCREASE IN
CONVECTION...IT IS UNCLEAR WHETHER NADINE WILL LOSE TROPICAL
CHARACTERISTICS AS QUICKLY AS INDICATED IN THE OFFICIAL FORECAST.
THE TRANSFORMATION TO A POST-TROPICAL CYCLONE IS SOMETHING THAT IS
DIFFICULT TO PREDICT...AND THERE IS LOW CONFIDENCE AS TO WHEN THIS
WILL OCCUR.
 
AFTER MEANDERING DURING MOST OF TODAY...SATELLITE IMAGES SUGGEST
THAT NADINE IS STARTING TO TURN EASTWARD.  HOWEVER...USING A LONGER
12-HOUR MOTION YIELDS AN INITIAL MOVEMENT OF EAST-NORTHEASTWARD AT
ABOUT 3 KT.  THE TRACK GUIDANCE HAS COME INTO BETTER AGREEMENT IN
TAKING NADINE SOUTHEASTWARD DURING THE NEXT 48 HOURS...IN
STRENGTHENING LOW- TO MID-LEVEL FLOW BETWEEN A DEEPING TROUGH TO
THE NORTHEAST OF THE CYCLONE AND A STRONG DEEP-LAYER RIDGE OVER THE
NORTH-CENTRAL ATLANTIC.  AFTER THAT TIME...THE GUIDANCE CONTINUES
TO SHOW TWO POSSIBLE SCENARIOS.  ONE SOLUTION...IS FOR NADINE TO BE
PULLED EASTWARD BY THE TROUGH...WHILE THE SECOND SCENARIO IS FOR
THE CYCLONE TO TURN SOUTHWESTWARD AROUND THE SOUTHEASTERN SIDE OF
THE CENTRAL-ATLANTIC RIDGE.  THE NHC TRACK FORECAST CONTINUES TO
REMAIN BETWEEN THESE PLAUSIBLE SCENARIOS...BUT THE NEW TRACK HAS
BEEN ADJUSTED SIGNIFICANTLY SOUTH OF THE PREVIOUS ADVISORY.  THIS
IS THE RESULT OF A FASTER SOUTHEASTWARD MOTION PREDICTED BY THE
GUIDANCE DURING THE FIRST 48 HOURS.  AT DAY 3 AND BEYOND...THE
OFFICIAL FORECAST SHOWS LITTLE OVERALL MOTION FOR NOW.
  
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  20/0300Z 37.1N  31.4W   45 KT  50 MPH
 12H  20/1200Z 36.6N  30.3W   45 KT  50 MPH
 24H  21/0000Z 35.5N  28.9W   45 KT  50 MPH...POST-TROPICAL
 36H  21/1200Z 34.2N  27.5W   45 KT  50 MPH...POST-TROPICAL
 48H  22/0000Z 32.8N  26.6W   45 KT  50 MPH...POST-TROPICAL
 72H  23/0000Z 32.0N  26.0W   45 KT  50 MPH...POST-TROPICAL
 96H  24/0000Z 31.5N  25.5W   45 KT  50 MPH...POST-TROPICAL
120H  25/0000Z 31.0N  25.0W   50 KT  60 MPH...POST-TROPICAL
 
$$
FORECASTER BROWN