382 
 WTPZ45 KNHC 200838
 TCDEP5
 TROPICAL STORM RICK DISCUSSION NUMBER  20
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP202009
 200 AM PDT TUE OCT 20 2009
  
 CONVENTIONAL AND MICROWAVE SATELLITE IMAGES INDICATE THAT RICK
 CONTINUES TO FEEL THE EFFECTS OF SOUTHWESTERLY SHEAR.  THE CLOUD
 PATTERN APPEARS RATHER DISORGANIZED...AND THE LOW-LEVEL CENTER IS
 EXPOSED TO THE SOUTHWEST OF A RECENT CONVECTIVE BURST. DVORAK FINAL
 T-NUMBERS OF 3.0 AND 3.5 FROM TAFB AND SAB...RESPECTIVELY...
 SUGGEST THAT SLOW WEAKENING HAS CONTINUED. BASED UPON THE LATEST
 INTENSITY ESTIMATES...THE INITIAL INTENSITY IS LOWERED TO 55 KT.
  
 UW-CIMSS SHEAR ANALYSES SUGGEST THAT 15-20 KT OF WEST-SOUTHWESTERLY
 SHEAR CONTINUES OVER RICK...AND GLOBAL MODELS INDICATE THIS SHOULD
 PERSIST THROUGH LANDFALL.  IN ADDITION....A FAIRLY DRY AND STABLE
 AIR MASS AT MID/UPPER-LEVELS LIES IMMEDIATELY WEST OF THE STORM
 CIRCULATION AND CONTINUES TO NEGATIVELY IMPACT THE CYCLONE.  THESE
 FACTORS SUGGEST ADDITIONAL...GRADUAL WEAKENING DURING THE NEXT DAY
 OR TWO...EVEN THOUGH SSTS INCREASE ALONG THE FORECAST TRACK.  THE
 OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS ONE...IN
 BEST AGREEMENT WITH THE SHIPS...LGEM...AND THE MODEL INTENSITY
 CONSENSUS.  IT SHOULD BE NOTED THAT THE GFDL AND HWRF FORECAST RICK
 TO RE-INTENSIFY TO A HURRICANE BEFORE LANDFALL.
  
 LATEST SATELLITE FIXES SUGGEST THAT RICK MAY HAVE TURNED TOWARD THE
 NORTH-NORTHEAST AND SLOWED DOWN DURING THE LAST SEVERAL HOURS...
 WITH THE LATEST INITIAL MOTION ESTIMATED AT 020/05.  WATER VAPOR
 IMAGERY SHOWS A VIGOROUS SHORTWAVE TROUGH CURRENTLY DIGGING INTO
 THE GREAT BASIN...AND GLOBAL MODELS INDICATE THAT THIS FEATURE
 SHOULD AMPLIFY FURTHER OVER THE INTERMOUNTAIN WEST DURING THE NEXT
 24-36 HOURS.  IN RESPONSE...MODEL GUIDANCE SHOWS RICK TURNING
 NORTHEASTWARD WITH INCREASING FORWARD SPEED THROUGH LANDFALL IN
 WESTERN MAINLAND MEXICO.  THE OFFICIAL FORECAST TRACK IS ADJUSTED
 FARTHER EAST TO MATCH THE TREND IN THE TRACK GUIDANCE AND MODEL
 CONSENSUS...BOTH SUGGESTING A SHARPER RECURVATURE.  ON THIS
 TRACK...RICK IS EXPECTED TO PASS SOUTH OF SOUTHERN BAJA CALIFORNIA
 IN ABOUT 24 HOURS AND INLAND OVER WESTERN MAINLAND MEXICO JUST
 AFTER 36 HOURS.
  
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      20/0900Z 19.4N 111.5W    55 KT
  12HR VT     20/1800Z 20.6N 110.9W    50 KT
  24HR VT     21/0600Z 22.0N 109.3W    50 KT
  36HR VT     21/1800Z 23.6N 107.3W    45 KT
  48HR VT     22/0600Z 25.5N 104.5W    20 KT...INLAND
  72HR VT     23/0600Z...DISSIPATED
  
 $$
 FORECASTER KIMBERLAIN