021  
WTNT44 KNHC 070844  
TCDAT4  
 
TROPICAL STORM RINA DISCUSSION NUMBER 5  
NWS NATIONAL HURRICANE CENTER MIAMI FL AL192017  
500 AM AST TUE NOV 07 2017  
 
RINA'S OVERALL CONVECTIVE CLOUD PATTERN HAS INCREASED IS AREAL  
COVERAGE IN THE EASTERN SEMICIRCLE, ALONG WITH A LITTLE MORE DEEP  
CONVECTION HAVING DEVELOPED NEAR THE WELL-DEFINED LOW-LEVEL CENTER.  
IN ADDITION, DRIFTING BUOY 41506, LOCATED ABOUT 40 NMI NORTHWEST OF  
THE CENTER, REPORTED A PRESSURE OF 1011.5 MB AT 0600 UTC, AND THAT  
DATUM WAS USED TO ESTIMATE THE CENTRAL PRESSURE OF 1009 MB.  
SATELLITE CLASSIFICATIONS FROM TAFB AND UW-CIMSS ADT REMAIN AT T2.5,  
SO THE INTENSITY IS BEING HELD AT 35 KT FOR THIS ADVISORY, WHICH  
COULD BE CONSERVATIVE GIVEN THE LOWER CENTRAL PRESSURE.  
 
THE INITIAL MOTION ESTIMATE IS 005/10 KT. THERE IS NO SIGNIFICANT  
CHANGE TO THE PREVIOUS FORECAST TRACK OR REASONING. AS RINA MOVES  
AROUND THE WESTERN PERIPHERY OF A STRONG DEEP-LAYER RIDGE, THE  
CYCLONE SHOULD CONTINUE TO ACCELERATE TOWARD THE NORTH TODAY AND  
THEN TOWARD THE NORTH-NORTHEAST ON WEDNESDAY. BY 48 HOURS, RINA IS  
EXPECTED TO GET CAUGHT UP IN THE MID-LATITUDE WESTERLIES AND  
ACCELERATE EVEN MORE TOWARD THE NORTHEAST OVER THE COLD WATERS  
OF THE NORTH ATLANTIC. THE NHC TRACK GUIDANCE HAS SHIFTED A LITTLE  
MORE TO LEFT, SO THE NEW OFFICIAL FORECAST TRACK HAS ALSO BEEN  
NUDGED IN THAT DIRECTION, CLOSE TO CONSENSUS MODELS TVCN AND HCCA.  
 
BASED ON GOES-16 ICE PHYSICS SATELLITE IMAGERY, THE INNER-CORE OF  
RINA'S CIRCULATION APPEARS TO HAVE TIGHTENED UP SOME AND HAS ALSO  
BECOME BETTER DEFINED. SOME MODEST STRENGTHENING IS FORECAST FOR  
THE NEXT 36 H OR SO DUE TO SOME BAROCLINIC FORCING ASSOCIATED WITH  
AN APPROACHING VIGOROUS SHORTWAVE TROUGH CURRENTLY LOCATED ABOUT 400  
NMI TO THE WEST. BY 48 H, THE CYCLONE WILL BE SITUATED OVER WATER  
TEMPERATURES COLDER THAN 20 DEG C AND WITHIN AN ENVIRONMENT OF  
INCREASING DEEP-LAYER WIND SHEAR. THE COMBINATION OF THOSE TWO  
NEGATIVE FACTORS ARE EXPECTED IS RESULT IN RINA BECOMING AN  
EXTRATROPICAL CYCLONE. THE NHC INTENSITY FORECAST IS SIMILAR TO THE  
HCCA INTENSITY CONSENSUS MODEL, AND ALSO INCLUDES INPUT FROM THE  
NOAA OCEAN PREDICTION CENTER.  
 
FORECAST POSITIONS AND MAX WINDS  
 
INIT 07/0900Z 31.4N 49.8W 35 KT 40 MPH  
12H 07/1800Z 33.7N 49.4W 40 KT 45 MPH  
24H 08/0600Z 37.0N 48.8W 45 KT 50 MPH  
36H 08/1800Z 40.4N 47.8W 45 KT 50 MPH  
48H 09/0600Z 44.4N 44.7W 45 KT 50 MPH...POST-TROP/EXTRATROP  
72H 10/0600Z 53.0N 32.0W 40 KT 45 MPH...POST-TROP/EXTRATROP  
96H 11/0600Z...DISSIPATED  
 

 
FORECASTER STEWART  
 
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