689 
 WTPZ45 KNHC 192035
 TCDEP5
 HURRICANE RICK DISCUSSION NUMBER  18
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP202009
 200 PM PDT MON OCT 19 2009
  
 DATA FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INDICATE
 THAT RICK HAS WEAKENED QUICKLY. THE MAXIMUM FLIGHT LEVEL WIND OF 76
 KT WAS FOUND IN THE NORTHEASTERN QUADRANT...WHILE THE PEAK SFMR
 WIND WAS 68 KT. THE INITIAL INTENSITY IS HELD CONSERVATIVELY AT
 85 KT FOR THIS PACKAGE...SINCE THE AIRCRAFT DID NOT SAMPLE SOME OF
 THE DEEPER CONVECTION LOCATED ABOUT 50 MI EAST OF THE CENTER. DATA
 FROM THE AIRCRAFT ALSO SUGGEST THAT THE 50-KT AND 34-KT WIND FIELDS
 HAVE EXPANDED...ESPECIALLY IN THE NORTHEASTERN QUADRANT...AS THE
 PREVIOUSLY TIGHT PRESSURE GRADIENT IN THE INNER CORE BEGINS TO
 RELAX.
  
 THE SHIPS MODEL AND UW-CIMSS ANALYSES CONTINUE TO SHOW 15 TO 20 KT
 OF WEST-SOUTHWESTERLY SHEAR OVER RICK. THE SHIPS FORECASTS THIS TO
 PERSIST FOR MOST OF THE NEXT 36 HOURS BEFORE INCREASING EVEN
 FURTHER. THE CYCLONE WILL ALSO BE MOVING INTO A DRIER MID-LEVEL
 ENVIRONMENT AFTER 24 HOURS. THIS SHOULD RESULT IN A STEADY
 WEAKENING OF THE CYCLONE. THE OFFICIAL FORECAST IS AGAIN ADJUSTED
 DOWNWARD IN AGREEMENT WITH THE ICON INTENSITY CONSENSUS THROUGH 24
 HOURS...AND THEN LEANS TOWARD THE SHIPS AND LGEM BEYOND THAT TIME.
 THE STATISTICAL MODELS SHOW CONTINUED WEAKENING...WHILE THE GFDL
 AND HWRF HOLD THE INTENSITY STEADY OR EVEN SHOW STRENGTHENING ON
 DAY 2...WHICH SEEMS UNREALISTIC CONSIDERING THE ENVIRONMENT THAT
 RICK WILL BE MOVING INTO.
  
 THE INITIAL MOTION ESTIMATE IS NOW TOWARD THE NORTH-NORTHWEST...
 330/06. THE TRACK GUIDANCE CONTINUES TO BE IN GOOD AGREEMENT ON RICK
 ACCELERATING TOWARD THE NORTH AND THEN TOWARD THE NORTHEAST AS IT
 RECURVES AHEAD OF A MID-LEVEL TROUGH THAT WILL BE MOVING INTO THE
 SOUTHWESTERN UNITED STATES IN THE NEXT COUPLE OF DAYS. THE
 MULTI-MODEL CONSENSUS...TVCN HAS CONTINUED TO SHIFT TO THE EAST...
 AND THE OFFICIAL FORECAST IS AGAIN NUDGED IN THAT DIRECTION.
 
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      19/2100Z 18.5N 111.7W    85 KT
  12HR VT     20/0600Z 19.2N 111.8W    75 KT
  24HR VT     20/1800Z 20.4N 111.1W    65 KT
  36HR VT     21/0600Z 21.9N 109.9W    55 KT
  48HR VT     21/1800Z 23.5N 108.2W    50 KT
  72HR VT     22/1800Z 25.5N 106.0W    20 KT...DISSIPATING INLAND
  96HR VT     23/1800Z...DISSIPATED
  
 $$
 FORECASTER BRENNAN/ROBERTS