483 
 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
  
 

This page was last modified on: Thu, Jul 23 2020 - 2003 UTC
Send comments to: Ryan Lyman