000 WTPZ45 KNHC 190834 TCDEP5 HURRICANE RICK DISCUSSION NUMBER 16 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP202009 200 AM PDT MON OCT 19 2009 AS RICK MOVES THROUGH A LESS CONDUCIVE ENVIRONMENT...THE CLOUD PATTERN HAS DEGRADED FURTHER WITH THE EYE NOW DIFFICULT TO DISCERN IN INFRARED SATELLITE IMAGES. WATER VAPOR IMAGERY SUGGEST THAT DRIER AIR IS INTRUDING FROM THE WEST INTO THE CIRCULATION. SOUTHWESTERLY SHEAR HAS INCREASED OVER THE HURRICANE...AND UPPER-LEVEL OUTFLOW IS BEING RESTRICTED OVER THE SOUTHWESTERN QUADRANT. INITIAL INTENSITY IS SOMEWHAT OF A GUESS SINCE THE DVORAK TECHNIQUE HAS BEEN KNOWN TO NOT WORK VERY WELL FOR WEAKENING TROPICAL CYCLONES. BLENDING THE T AND CURRENT INTENSITY NUMBERS FROM TAFB AND SAB YIELDED 115 KT AT 0600 UTC AND SINCE THE CLOUD PATTERN HAS DETERIORATED A LITTLE MORE SINCE THEN THE ADVISORY INTENSITY IS SET AT 110 KT. AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT IS SCHEDULED TO INVESTIGATE RICK LATER TODAY AND SHOULD PROVIDE A GOOD ESTIMATE OF THE STRENGTH OF THE HURRICANE. EVEN THOUGH ADDITIONAL WEAKENING IS LIKELY DURING THE NEXT 48 HOURS OR SO...THE ENVIRONMENT IS NOT EXPECTED TO BECOME SO HOSTILE AS TO WEAKEN RICK BELOW HURRICANE STATUS BY THE TIME IT MOVES NEAR OR OVER SOUTHERN BAJA CALIFORNIA. THE OFFICIAL INTENSITY FORECAST IS A LITTLE ABOVE THE MODEL CONSENSUS AND SIMILAR TO THE PREVIOUS NHC FORECAST. THE INITIAL MOTION HAS SLOWED SOME MORE AND IS NOW NEAR 305/9. THE MID-LEVEL RIDGE TO THE NORTH OF RICK CONTINUES TO WEAKEN AS A MID-TROPOSPHERIC SHORTWAVE TROUGH MOVES THROUGH CALIFORNIA. A SECOND SHORTWAVE IS PREDICTED BY THE GLOBAL MODELS TO DROP INTO THE SOUTHWESTERN U.S. IN A DAY OR SO. RICK IS LIKELY TO TURN NORTHWARD INTO THE WEAKNESS CAUSED BY THE FIRST TROUGH. THEN...THE HURRICANE SHOULD VEER TOWARD THE NORTH-NORTHEAST AND NORTHEAST WITH AN INCREASE IN FORWARD SPEED DUE TO THE INFLUENCE OF THE SECOND TROUGH. THE OFFICIAL TRACK FORECAST IS VERY SIMILAR TO THE PREVIOUS ONE...AND LIES ABOUT IN THE MIDDLE OF THE DYNAMICAL GUIDANCE SUITE EXCLUDING THE U.K. MET. OFFICE RUN. THE ENVELOPE OF THIS SUITE IS BRACKETED BY THE ECMWF TRACK...WHICH IS THE SOUTHERNMOST MODEL AND THE HWRF MODEL...WHICH IS THE NORTHERNMOST. THE U.K. MET. OFFICE MODEL CONTINUES TO BE AN UNREALISTIC-LOOKING OUTLIER SINCE IT SHOWS LITTLE NET MOTION OF RICK OVER THE NEXT SEVERAL DAYS. SINCE RICK COULD MOVE A LITTLE FASTER THAN EXPECTED AND THE CURRENT AND PREDICTED EXTENT OF TROPICAL STORM FORCE WINDS IS SOMEWHAT UNCERTAIN...A HURRICANE WATCH HAS BEEN ISSUED FOR EXTREME SOUTHERN BAJA CALIFORNIA AT THIS TIME. FORECAST POSITIONS AND MAX WINDS INITIAL 19/0900Z 17.5N 111.1W 110 KT 12HR VT 19/1800Z 18.4N 111.8W 105 KT 24HR VT 20/0600Z 19.5N 112.1W 100 KT 36HR VT 20/1800Z 20.8N 111.5W 90 KT 48HR VT 21/0600Z 22.3N 110.2W 85 KT 72HR VT 22/0600Z 25.5N 107.0W 50 KT...INLAND 96HR VT 23/0600Z...DISSIPATED $$ FORECASTER PASCH