Tropical Storm RINA

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TROPICAL STORM RINA DISCUSSION NUMBER  19
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL182011
400 PM CDT THU OCT 27 2011
 
SATELLITE IMAGERY...RADAR DATA...AND REPORTS FROM AN AIR FORCE
RESERVE HURRICANE HUNTER INDICATE THAT RINA CONTINUES TO WEAKEN.
THE PREVIOUSLY OBSERVED STRONG CONVECTIVE BURST HAS DISSIPATED...AND
THERE IS CURRENTLY LITTLE CONVECTION NEAR THE CENTER.  THE AIRCRAFT
HAS REPORTED MAXIMUM 850 MB FLIGHT-LEVEL WINDS OF 58 KT AND SURFACE
WIND ESTIMATES OF 48 KT FROM THE STEPPED FREQUENCY MICROWAVE
RADIOMETER.  BASED ON THESE DATA...THE INITIAL INTENSITY IS
DECREASED TO 50 KT.
 
THE INITIAL MOTION IS NOW 350/6.  THE TROPICAL CYCLONE SHOULD MOVE
SLOWLY NORTHWARD NEAR THE EAST COAST OF THE YUCATAN PENINSULA FOR
THE NEXT 12-24 HOURS ON THE WEST SIDE OF A MID/UPPER-LEVEL RIDGE
OVER THE CARIBBEAN SEA.  AFTER THAT...THE DYNAMICAL MODELS ARE IN
GOOD AGREEMENT THAT A COMBINATION OF RINA WEAKENING TO A SHALLOW
VORTEX AND RISING LOW-LEVEL PRESSURES TO ITS NORTHWEST SHOULD CAUSE
RINA TO TURN SOUTHWARD.  WHILE THERE REMAIN DIFFERENCES IN THE
DETAILS...THE GUIDANCE SUGGESTS THAT RINA OR ITS REMNANTS WILL
MEANDER OVER THE NORTHWEST CARIBBEAN SEA OR THE ADJACENT LAND AREAS
FOR THE REST OF THE FORECAST PERIOD.  THE FORECAST TRACK AFTER 48
HOURS SHOWS A SLIGHTLY FASTER SOUTHWARD AND THEN SOUTH-
SOUTHWESTWARD MOTION THAN THE OLD FORECAST.  WHILE THIS TRACK IS
NEAR THE CENTER OF THE TRACK GUIDANCE ENVELOPE...THE SOUTHWARD
MOTION IS SLOWER THAN THAT OF MOST OF THE DYNAMICAL GUIDANCE.
 
MODERATE TO STRONG SOUTHERLY VERTICAL WIND SHEAR IS LIKELY TO
PERSIST NEAR OR OVER RINA FOR THE NEXT 72 HOURS OR SO.  THIS...
ALONG WITH LAND INTERACTION AND DRY AIR ENTRAINING INTO THE
CYCLONE...SHOULD CAUSE CONTINUED WEAKENING.  BASED ON THIS AND THE
CURRENT TRENDS...THE NEW INTENSITY FORECAST CALLS FOR RINA TO MEET
AN EARLIER DEMISE THAN ON THE PREVIOUS ADVISORY...WITH THE CYCLONE
EXPECTED TO WEAKEN TO A TROPICAL DEPRESSION BY 48 HOURS AND TO
DEGENERATE TO A REMNANT LOW BY 72 HOURS.  THE DYNAMICAL MODELS
SUGGEST THE SHEAR MAY DECREASE AFTER 72 HOURS.  HOWEVER...GIVEN THE
UNCERTAINTIES OF THE STRUCTURE AND LOCATION OF THE REMNANTS OF RINA
THE FORECAST OF REMNANT LOW AT 120 HOURS WILL REMAIN UNCHANGED.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  27/2100Z 19.8N  87.2W   50 KT  60 MPH
 12H  28/0600Z 20.6N  87.2W   45 KT  50 MPH...INLAND
 24H  28/1800Z 21.3N  87.1W   40 KT  45 MPH...INLAND
 36H  29/0600Z 21.2N  86.5W   35 KT  40 MPH...OVER WATER
 48H  29/1800Z 20.9N  86.1W   30 KT  35 MPH
 72H  30/1800Z 20.0N  86.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  31/1800Z 18.5N  86.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  01/1800Z 17.0N  87.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
 
$$
FORECASTER BEVEN
 
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