Tropical Storm ROSA

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TROPICAL STORM ROSA DISCUSSION NUMBER   2
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP172012
800 AM PDT TUE OCT 30 2012
 
SATELLITE IMAGES INDICATE THAT STRONG CONVECTION HAS PERSISTED IN
THE EASTERN SEMICIRCLE OF THE CYCLONE FOR THE PAST SEVERAL HOURS
ALONG WITH INCREASED BANDING FEATURES.  THE CENTER APPEARS TO BE
EMBEDDED WITHIN THE NORTHWESTERN EDGE OF THE DEEP CONVECTION...
ALTHOUGH THERE HAVE BEEN NO RECENT MICROWAVE IMAGES TO CONFIRM THIS
APPEARANCE.  SATELLITE INTENSITY ESTIMATES ARE BOTH 35 KT FROM TAFB
AND SAB...AND THUS THAT IS THE INITIAL WIND SPEED.  MOST OF THE
MODEL GUIDANCE SHOW A LITTLE BIT OF STRENGTHENING OVER THE NEXT DAY
OR SO WHILE ROSA REMAINS WITHIN LIGHT WIND SHEAR.  HOWEVER...WATER
VAPOR IMAGES INDICATE THAT HIGHER SHEAR IS NOT FAR AWAY WITH
WESTERLY WINDS LOCATED ONLY A COUPLE HUNDRED MILES NORTH OF THE
CENTER.  THE CYCLONE SHOULD ENCOUNTER THESE STRONGER WINDS ON
THURSDAY...WHICH SHOULD PROMOTE WEAKENING.  THE OFFICIAL FORECAST
IS CLOSE TO THE PREVIOUS ONE...ON THE HIGHER SIDE OF THE GUIDANCE
ENVELOPE INITIALLY THEN BLENDED BACK TOWARD THE CONSENSUS.
 
AN UNCERTAIN INITIAL MOTION ESTIMATE IS 290/6. THE CYCLONE SHOULD
MOVE FAIRLY SLOWLY TO THE WEST-NORTHWEST AND WEST OVER THE NEXT
COUPLE OF DAYS DUE TO A RIDGE OVER THE EASTERN PACIFIC. AFTER THAT
TIME...ANOTHER RIDGE FORMS TO THE NORTHWEST OF A WEAKENING ROSA...
WHICH SHOULD LEAD TO A MORE WEST-SOUTHWEST MOTION. THE GFS REMAINS
ON THE FASTER SIDE OF THE GUIDANCE ENVELOPE...WITH MOST OF THE
OTHER AIDS BEING A BIT SLOWER. THE OFFICIAL FORECAST IS CLOSE TO
THE PREVIOUS FORECAST AND NEAR THE DYNAMICAL MODEL CONSENSUS TVCE.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  30/1500Z 14.5N 116.5W   35 KT  40 MPH
 12H  31/0000Z 14.8N 117.3W   40 KT  45 MPH
 24H  31/1200Z 15.1N 118.6W   45 KT  50 MPH
 36H  01/0000Z 15.4N 119.6W   40 KT  45 MPH
 48H  01/1200Z 15.4N 120.3W   35 KT  40 MPH
 72H  02/1200Z 15.0N 121.5W   30 KT  35 MPH...POST-TROP/REMNT LOW
 96H  03/1200Z 13.5N 123.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  04/1200Z...DISSIPATED
 
$$
FORECASTER BLAKE
 
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