000 WTNT43 KNHC 240243 TCDAT3 TROPICAL STORM RINA DISCUSSION NUMBER 2 NWS NATIONAL HURRICANE CENTER MIAMI FL AL182011 1100 PM EDT SUN OCT 23 2011 EARLIER REPORTS FROM AN AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT INDICATED BELIEVABLE SFMR WINDS OF 33-35 KT OUTSIDE OF THE CONVECTION IN THE SOUTHWESTERN QUADRANT OF THE CYCLONE...BUT THESE WINDS COULD HAVE BEEN GUSTS. THE AIRCRAFT ALSO HAD TO AVOID STRONG THUNDERSTORMS TO THE NORTH OF THE CENTER AND WAS... THEREFORE... UNABLE TO SAMPLE THE WINDS IN THAT AREA. SINCE THEN... HOWEVER... DEEP CONVECTION HAS INCREASED MARKEDLY IN THE NORTHERN SEMICIRCLE AND CONVECTION HAS ALSO DEVELOPED IN THE SOUTHWESTERN QUADRANT... WHICH IS LIKELY HELPING TO SUSTAIN THE STRONGER WINDS IN THAT REGION AS REPORTED PREVIOUSLY. UW-CIMSS ADT ESTIMATES HAVE BEEN STEADILY INCREASING...AND THE MOST RECENT 2-HOUR AVERAGE IS T2.7/39 KT. AS A RESULT...THE DEPRESSION HAS BEEN UPGRADED TO TROPICAL STORM RINA...THE SEVENTEENTH NAMED STORM OF THE SEASON. RINA IS FORECAST TO REMAIN OVER SSTS OF NEAR 30C FOR THE NEXT 72-96 HOURS. IN ADDITION...DURING THE 24-48 HOUR TIME PERIOD...THE CYCLONE WILL BE MOVING OVER SOME VERY HIGH UPPER-OCEAN CONTENT THAT IS MORE THAN 10 TIMES THE VALUE THE STORM IS CURRENTLY TRAVERSING. THE UPPER-LEVEL OUTFLOW HAS BEEN STEADILY INCREASING AND IS EXPECTED TO IMPROVE EVEN MORE THROUGH 72 HOURS AS RINA MOVES UNDER AN UPPER-LEVEL RIDGE AXIS THAT WILL PRODUCE OUTFLOW CHANNELS TO THE NORTH AND SOUTH. SO THERE IS PLENTY OF HEAT AND VENTILATION AVAILABLE FOR STRENGTHENING TO OCCUR. THE ONLY POSSIBLE INHIBITING FACTOR IS VERY DRY MID-LEVEL AIR LOCATED OVER THE SOUTHERN GULF OF MEXICO AND YUCATAN CHANNEL...WHICH COULD BE ENTRAINED INTO THE CYCLONE AT 48 HOURS AND BEYOND. AS A RESULT...THE INTENSITY FORECAST WILL REMAIN ON THE CONSERVATIVE SIDE AND LIES CLOSE TO THE INTENSITY CONSENSUS MODEL ICON...AND THE STATISTICAL-DYNAMICAL MODEL...LGEM. THE INITIAL MOTION ESTIMATE IS 335/7 KT BASED ON RECON FIXES. THE FORECAST TRACK DEPENDS HEAVILY ON THE INTENSITY FORECAST. SINCE THE OFFICIAL INTENSITY FORECAST IS MUCH MORE ROBUST THAN WHAT THE GFS...NOGAPS...CANADIAN...AND GFDL MODELS ARE FORECASTING FOR THE NEXT 48 HOURS AND BEYOND...THOSE MODEL SOLUTIONS OF A WESTWARD OR EVEN WEST-SOUTHWESTWARD MOTION FROM THE CURRENT POSITION HAVE BEEN DISCOUNTED. IN CONTRAST...THE HWRF AND UKMET MODELS ARE FORECASTING A STRONGER AND DEEPER CYCLONE THROUGHOUT THE THE FORECAST PERIOD... WHICH LOOKS MORE LIKELY GIVEN THE RECENT UPWARD TRENDS IN SATELLITE AND UPPER-AIR DATA. AS A RESULT...THE EXPECTED FORECAST SCENARIO CALLS FOR RINA TO MOVE NORTHWESTWARD THROUGH A WEAKNESS IN THE SUBTROPICAL RIDGE FOR THE NEXT 12 HOURS OR SO. AS A VIGOROUS SHORTWAVE TROUGH CURRENTLY MOVING EASTWARD ACROSS THE CENTRAL AND EASTERN GULF OF MEXICO PASSES EAST OF FLORIDA TOMORROW...THE RIDGE SHOULD BUILD BACK IN TO THE NORTH OF RINA...FORCING THE CYCLONE ON A SLOW WEST-NORTHWESTWARD TRACK UNTIL DAY 4. AFTER THAT...ANOTHER STRONG SHORTWAVE TROUGH IS FORECAST TO DIG SOUTHEASTWARD FROM THE SOUTHERN PLAINS AND INTO THE GULF OF MEXICO...WHICH IS EXPECTED TO WEAKEN THE SUBTROPICAL RIDGE ONCE AGAIN AND ALLOW RINA TO TURN NORTHWARD NEAR THE YUCATAN PENINSULA. THE OFFICIAL FORECAST TRACK LIES TO THE RIGHT OF THE PREVIOUS ADVISORY TRACK AND THE CONSENSUS MODELS..AND IS CLOSE TO A BLEND OF THE UKMET...HWRF...AND ECMWF MODEL TRACKS. IN THE SHORT TERM...HEAVY RAINFALL AND FLOODING WILL BE SIGNIFICANT THREATS FOR NORTHERN HONDURAS WHERE 8-15 INCHES OF RAIN HAVE ALREADY FALLEN DURING THE PAST 3 DAYS. FORECAST POSITIONS AND MAX WINDS INIT 24/0300Z 16.4N 82.2W 35 KT 40 MPH 12H 24/1200Z 16.8N 82.6W 40 KT 45 MPH 24H 25/0000Z 17.3N 83.4W 45 KT 50 MPH 36H 25/1200Z 17.5N 84.3W 50 KT 60 MPH 48H 26/0000Z 17.7N 85.1W 55 KT 65 MPH 72H 27/0000Z 17.9N 86.2W 60 KT 70 MPH 96H 28/0000Z 18.9N 87.4W 65 KT 75 MPH 120H 29/0000Z 20.0N 87.4W 65 KT 75 MPH $$ FORECASTER STEWART