000 WTPZ42 KNHC 301441 TCDEP2 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