000 WTNT43 KNHC 252054 TCDAT3 HURRICANE RINA DISCUSSION NUMBER 10 NWS NATIONAL HURRICANE CENTER MIAMI FL AL182011 500 PM EDT TUE OCT 25 2011 DATA FROM THE AIR FORCE HURRICANE HUNTER AIRCRAFT INDICATE THAT RINA HAS INTENSIFIED A LITTLE THIS AFTERNOON. THE INITIAL INTENSITY IS RAISED TO 95 KT BASED ON A PEAK SFMR WIND OF 94 KT AND 700-MB FLIGHT-LEVEL WIND MAXIMUM OF 106 KT. THE LATEST CENTRAL PRESSURE MEASURED FROM THE PLANE WAS 970 MB...FALLING A LITTLE OVER THE PAST FEW HOURS. THE ENVIRONMENT APPEARS FAVORABLE FOR SOME ADDITIONAL INTENSIFICATION DURING THE NEXT DAY OR TWO AS THE CYCLONE MOVES OVER VERY WARM WATERS IN A REGION OF LOW WIND SHEAR. THE OFFICIAL FORECAST SHOWS A BROAD PEAK AT 100 KT FROM 12 TO 48 HOURS...A LITTLE ABOVE THE SHIPS AND LGEM MODELS. AFTER THAT TIME...RINA WILL BE MOVING INTO A REGION OF INCREASING VERTICAL SHEAR...WHICH SHOULD RESULT IN WEAKENING. THE NEW NHC FORECAST IS SIMILAR TO THE PREVIOUS ONE AT DAYS 3 THROUGH 5...FOLLOWING THE SHIPS AND LGEM. HOWEVER...IF RINA MOVES FARTHER INLAND OVER THE YUCATAN PENINSULA THAN EXPECTED...IT COULD BE WEAKER THAN FORECAST IN 2 OR 3 DAYS. AIRCRAFT FIXES INDICATE THAT RINA HAS JOGGED TOWARD THE LEFT OVER THE PAST FEW HOURS...WITH THE INITIAL MOTION NOW 270/04. THE TRACK FORECAST REASONING REMAINS UNCHANGED IN THE SHORT TERM...AS RINA SHOULD BEGIN TO TURN POLEWARD AROUND THE WESTERN EDGE OF THE SUBTROPICAL RIDGE. THE TRACK GUIDANCE REMAINS IN GOOD AGREEMENT ON THIS SCENARIO...AND ONLY A SLIGHT WESTWARD ADJUSTMENT WAS MADE TO THE OFFICIAL FORECAST THROUGH 48 HOURS. AFTER THE CYCLONE PASSES BY THE YUCATAN PENINSULA...SIGNIFICANT SPREAD DEVELOPS IN THE GUIDANCE. THE TRACK AND INTENSITY FORECASTS ARE CLOSELY LINKED LATE IN THE PERIOD. ON ONE EXTREME...THE ECMWF WEAKENS RINA AND DISSIPATES IT OVER THE CENTRAL GULF OF MEXICO AFTER 72 HOURS... WHILE THE GFS AND HWRF TAKE A STRONGER CYCLONE QUICKLY TOWARD THE NORTHEAST AHEAD OF A BROAD MID/UPPER-LEVEL TROUGH. MUCH OF THE REST OF THE GUIDANCE LIES BETWEEN THESE TWO CAMPS...BUT THE OVERALL TREND IS NORTH OF THE PREVIOUS NHC FORECAST. THE NHC FORECAST HAS BEEN ADJUSTED IN THAT DIRECTION...BUT A SLOW MOTION IS SHOWN AT DAYS 4 AND 5 DUE TO THE LARGE SPREAD IN THE GUIDANCE. NEEDLESS TO SAY...THE CONFIDENCE IN THE LATTER PART OF THE TRACK FORECAST REMAINS VERY LOW. FORECAST POSITIONS AND MAX WINDS INIT 25/2100Z 17.4N 84.3W 95 KT 110 MPH 12H 26/0600Z 17.5N 85.2W 100 KT 115 MPH 24H 26/1800Z 18.3N 86.1W 100 KT 115 MPH 36H 27/0600Z 19.4N 86.8W 100 KT 115 MPH 48H 27/1800Z 20.8N 86.9W 100 KT 115 MPH 72H 28/1800Z 22.5N 86.0W 80 KT 90 MPH 96H 29/1800Z 23.5N 84.0W 60 KT 70 MPH 120H 30/1800Z 23.5N 82.5W 45 KT 50 MPH $$ FORECASTER BRENNAN