000 WTNT43 KNHC 260249 TCDAT3 HURRICANE RINA DISCUSSION NUMBER 11 NWS NATIONAL HURRICANE CENTER MIAMI FL AL182011 1100 PM EDT TUE OCT 25 2011 THE EYE BECAME OBSCURED ON CONVENTIONAL SATELLITE IMAGERY...AND CONSEQUENTLY T-NUMBERS FROM SAB AND TAFB HAVE DECREASED A LITTLE BIT. HOWEVER...LATEST MICROWAVE DATA SHOW A DISTINCT EYE FEATURE WHICH IS BETTER DEFINED THAN IN EARLIER DATA. A NOAA HURRICANE HUNTER PLANE INVESTIGATING THE HURRICANE MEASURED A LOWER MINIMUM PRESSURE OF 966 MB...BUT NEITHER SFMR OR FLIGHT-LEVEL WINDS INDICATE THAT RINA IS STRONGER THAN A FEW HOURS AGO. THE INITIAL INTENSITY IS KEPT AT 95 KNOTS IN THIS ADVISORY. GIVEN THE FAVORABLE LOW-SHEAR ENVIRONMENT AND THE VERY HIGH OCEANIC HEAT CONTENT PREVAILING IN THE NORTHWESTERN CARIBBEAN SEA...RINA COULD BECOME A MAJOR HURRICANE AT ANY TIME BEFORE REACHING EASTERN YUCATAN. THEREAFTER...RINA WILL FIND A VERY HOSTILE ENVIRONMENT OF STRONG SHEAR OVER THE EXTREME SOUTHERN GULF OF MEXICO WHICH MOST LIKELY WILL WEAKEN THE CYCLONE SIGNIFICANTLY. RINA HAS BEEN DRIFTING WESTWARD ABOUT 3 KNOTS...TRAPPED SOUTH OF A STRONG SUBTROPICAL HIGH PRESSURE RIDGE. BUT SOON...THE HIGH WILL SHIFT EASTWARD...AND THE HURRICANE SHOULD BEGIN TO MOVE...STILL VERY SLOWLY...TOWARD THE NORTHWEST AND NORTH AROUND THE PERIPHERY OF THE RIDGE. THE CYCLONE IS FORECAST TO BE OVER THE NORTHWESTERN CARIBBEAN SEA AND BE VERY NEAR NORTHEASTERN YUCATAN IN 48 HOURS. THERE IS RELATIVELY HIGH CONFIDENCE IN THIS PORTION OF THE FORECAST SINCE MOST OF THE GUIDANCE IS QUITE CONSISTENT WITH THIS MOTION. BEYOND 48 HOURS...AS RINA BEGINS TO INTERACT WITH THE MID-LATITUDE WESTERLY FLOW...THE FORECAST BECOMES HIGHLY UNCERTAIN SINCE THE MODEL SPREAD INCREASES CONSIDERABLY. BY THEN...RINA EITHER RECURVES OVER THE SOUTHEASTERN GULF OF MEXICO OR MEANDERS NEAR YUCATAN AS A SHALLOW CYCLONE STEERED BY THE LOW-LEVEL FLOW. THE NHC FORECAST CALLS FOR RECURVATURE AND BRINGS A WEAKENING RINA NEAR THE NORTH COAST OF WESTERN CUBA. THIS IS CONSISTENT WITH THE PREVIOUS NHC FORECAST. FORECAST POSITIONS AND MAX WINDS INIT 26/0300Z 17.5N 84.8W 95 KT 110 MPH 12H 26/1200Z 17.9N 85.4W 100 KT 115 MPH 24H 27/0000Z 19.0N 86.4W 100 KT 115 MPH 36H 27/1200Z 20.2N 86.8W 100 KT 115 MPH 48H 28/0000Z 21.3N 86.7W 85 KT 100 MPH 72H 29/0000Z 23.0N 85.0W 75 KT 85 MPH 96H 30/0000Z 23.5N 83.0W 60 KT 70 MPH 120H 31/0000Z 23.5N 82.5W 45 KT 50 MPH $$ FORECASTER AVILA/BERG