000 WTNT43 KNHC 241438 TCDAT3 TROPICAL STORM RINA DISCUSSION NUMBER 4 NWS NATIONAL HURRICANE CENTER MIAMI FL AL182011 1100 AM EDT MON OCT 24 2011 VISIBLE SATELLITE IMAGES SHOW THAT RINA HAS BECOME BETTER ORGANIZED WITH THE CENTER LOCATED WELL WITHIN THE LARGE AREA OF DEEP CONVECTION. THE LATEST DVORAK DATA T AND CI NUMBERS... AND A RECENT AMSU INTENSITY ESTIMATE SUPPORT INCREASING THE INITIAL WIND SPEED TO 40 KT. AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT IS SCHEDULED TO INVESTIGATE THE CYCLONE THIS AFTERNOON AND SHOULD PROVIDE A BETTER ASSESSMENT OF THE INTENSITY OF RINA. ALTHOUGH THERE IS SOME DRY AIR TO THE NORTHWEST OF THE CYCLONE... AN INCREASINGLY FAVORABLE UPPER-LEVEL WIND PATTERN AND VERY WARM WATERS OF THE NORTHWESTERN CARIBBEAN SEA SHOULD ALLOW FOR STEADY STRENGTHENING DURING THE NEXT 48-72 HOURS. IN 3 TO 4 DAYS... SOUTHERLY SHEAR IS EXPECTED TO INCREASE...AND LATER IN THE PERIOD...THE CYCLONE IS FORECAST TO INTERACT WITH A FRONTAL BOUNDARY. THESE CONDITIONS WILL LIKELY LEAD TO SOME WEAKENING OF RINA BEFORE THE END OF THE FORECAST PERIOD. THE UPDATED NHC INTENSITY FORECAST IS ABOVE THE PREVIOUS ADVISORY AND LIES BETWEEN THE STATISTICAL SHIPS/LGEM GUIDANCE AND THE MORE AGGRESSIVE GFDL/HWRF MODELS. RECENT GEOSTATIONARY AND MICROWAVE SATELLITE FIXES SUGGEST THAT RINA IS BEGINNING ITS TURN TOWARD THE LEFT. THE INITIAL MOTION ESTIMATE IS 320/5. THE CYCLONE SHOULD TURN WEST-NORTHWESTWARD TODAY AS A MID-LEVEL RIDGE BUILDS OVER THE NORTHERN GULF OF MEXICO DURING THE NEXT 24 HOURS. AS THIS RIDGE SLIDES EASTWARD IN A COUPLE OF DAYS...IT SHOULD ALLOW RINA TO TURN NORTHWESTWARD...THEN NORTHWARD. NEAR THE END OF THE FORECAST PERIOD...RINA IS EXPECTED TO TURN NORTHEASTWARD AS THE RIDGE RETREATS AND A BROAD TROUGH MOVES OVER THE GULF OF MEXICO. THE MODEL GUIDANCE IS IN SOMEWHAT BETTER AGREEMENT THIS CYCLE...WITH THE GFDL AND HWRF SHIFTING SOUTHWARD AND KEEPING RINA OVER THE NORTHWESTERN CARIBBEAN SEA DURING THE FORECAST PERIOD. THE NHC FORECAST IS VERY SIMILAR TO THE PREVIOUS ADVISORY THROUGH 96 HOURS...BUT NOW SHOWS A SLOW NORTHEASTWARD MOTION THEREAFTER. THE NEW TRACK IS IN GOOD AGREEMENT WITH BOTH THE TVCA AND HFIP MULTI-MODEL CONSENSUS. FORECAST POSITIONS AND MAX WINDS INIT 24/1500Z 17.1N 82.9W 40 KT 45 MPH 12H 25/0000Z 17.4N 83.4W 50 KT 60 MPH 24H 25/1200Z 17.6N 84.0W 60 KT 70 MPH 36H 26/0000Z 17.8N 84.8W 70 KT 80 MPH 48H 26/1200Z 18.1N 85.7W 80 KT 90 MPH 72H 27/1200Z 19.2N 87.0W 75 KT 85 MPH 96H 28/1200Z 20.5N 87.0W 65 KT 75 MPH 120H 29/1200Z 21.0N 86.0W 55 KT 65 MPH $$ FORECASTER BROWN/ROBERTS