105  
WTNT44 KNHC 090236  
TCDAT4  
 
TROPICAL STORM RINA DISCUSSION NUMBER 12  
NWS NATIONAL HURRICANE CENTER MIAMI FL AL192017  
1100 PM AST WED NOV 08 2017  
 
A SMALL AREA OF DEEP CONVECTION PERSISTS NEAR THE CENTER OF RINA,  
LIKELY SUPPORTED BY VERY COLD TEMPERATURES ALOFT AND INCREASING  
UPPER-LEVEL DIVERGENCE OVERCOMING SSTS LESS THAN 20C. THE INITIAL  
INTENSITY REMAINS 45 KT BASED LARGELY ON CONTINUITY FROM THE ASCAT  
PASS EARLIER TODAY, AS THE LATEST ASCAT PASSES MISSED MUCH OF RINA'S  
CIRCULATION. GIVEN THE MAINTENANCE OF DEEP CONVECTION, RINA REMAINS  
A TROPICAL CYCLONE, BUT SHOULD NOT BE ONE FOR LONG AS VERTICAL  
SHEAR IS EXPECTED TO INCREASE ABOVE 30 KT AND SSTS COOL BELOW 15C  
ALONG THE FORECAST TRACK IN THE NEXT 12 HOURS. THE CYCLONE SHOULD  
BECOME POST-TROPICAL BY 12 HOURS AND MERGE WITH A FRONTAL ZONE BY 24  
HOURS. POST-TROPICAL RINA SHOULD OPEN UP INTO A TROUGH IN 36 TO 48  
HOURS IN THE FAST WESTERLY FLOW OVER THE NORTH ATLANTIC. NO CHANGE  
IN STRENGTH IS FORECAST PRIOR TO DISSIPATION, BASED ON GLOBAL MODEL  
GUIDANCE.  
 
SATELLITE FIXES INDICATE THAT RINA MOVED A LITTLE TO THE WEST OF THE  
PREVIOUS FORECAST TRACK IN THE PAST FEW HOURS, BUT THE CYCLONE NOW  
APPEARS TO BE MOVING NORTH-NORTHEASTWARD OR 020/20. THE CYCLONE IS  
FORECAST TO ACCELERATE NORTHEASTWARD OVER THE NEXT 24 HOURS AS IT  
BECOMES EMBEDDED IN THE MID-LATITUDE FLOW, AND AN EVEN FASTER EAST-  
NORTHEASTWARD MOTION IS EXPECTED ON FRIDAY PRIOR TO DISSIPATION. THE  
NEW NHC TRACK FORECAST HAS BEEN ADJUSTED TO THE LEFT AND IS CLOSER  
TO THE ECMWF MODEL IN THE SHORT RANGE, SINCE THAT MODEL HAS BEST  
HANDLED THE RECENT MOTION OF RINA. AT 24 TO 36 HOURS, THE NHC  
FORECAST LIES TO THE LEFT OF THE LATEST MULTI-MODEL CONSENSUS AIDS.  
 
THE TRACK, INTENSITY AND STRUCTURE FORECASTS OF RINA DURING ITS  
POST-TROPICAL PHASE HAVE BEEN COORDINATED WITH THE NOAA OCEAN  
PREDICTION CENTER.  
 
FORECAST POSITIONS AND MAX WINDS  
 
INIT 09/0300Z 42.5N 48.3W 45 KT 50 MPH  
12H 09/1200Z 45.7N 46.5W 45 KT 50 MPH...POST-TROPICAL  
24H 10/0000Z 51.0N 40.0W 45 KT 50 MPH...POST-TROP/EXTRATROP  
36H 10/1200Z 55.0N 26.5W 45 KT 50 MPH...POST-TROP/EXTRATROP  
48H 11/0000Z...DISSIPATED  
 

 
FORECASTER BRENNAN  
 
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