296 
 WTPZ45 KNHC 200251
 TCDEP5
 TROPICAL STORM RICK DISCUSSION NUMBER  19
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP202009
 800 PM PDT MON OCT 19 2009
  
 RICK HAS BEEN WEAKENING AT A RAPID PACE...ALMOST AS FAST AS IT
 STRENGTHENED SEVERAL DAYS AGO.  CONVENTIONAL AND MICROWAVE SATELLITE
 DATA SHOW THAT THE LOW-LEVEL CENTER IS NOW COMPLETELY EXPOSED TO
 THE WEST AND SOUTHWEST OF A SHAPELESS CLUSTER OF DEEP CONVECTION. 
 DVORAK FINAL-T AND CI NUMBERS ARE NOW 3.5/4.5 FROM TAFB AND
 SAB...BUT BOTH AGENCIES WERE CONSTRAINED BY THE DVORAK RULES AND
 ACTUALLY HAD DATA T-NUMBERS OF 3.0.  IN ADDITION...THE LATEST
 UW-CIMMS ADT 3-HOUR ESTIMATE IS 3.1 WITH A CI OF 3.6.  THEREFORE...
 RICK IS DOWNGRADED TO A 60-KT TROPICAL STORM.
 
 STRONG UPPER-LEVEL WESTERLY WINDS AND DRY...STABLE AIR TO THE WEST
 OF RICK ARE THE LIKELY CAUSES FOR THE RAPID WEAKENING OF RICK OVER
 THE PAST DAY OR SO.  SINCE THE SHEAR IS NOT EXPECTED TO ABATE AND
 THE AMBIENT ENVIRONMENT IS FORECAST TO REMAIN STABLE...RICK SHOULD
 CONTINUE TO WEAKEN OVER THE NEXT COUPLE OF DAYS.  THE NEW INTENSITY
 FORECAST IS SIGNIFICANTLY LOWER THAN THE PREVIOUS ONE DUE TO THE
 RECENT WEAKENING TREND...BUT IT IS STILL HIGHER THAN THAT SHOWN BY
 THE STATISTICAL SHIPS AND LGEM MODELS.  ALL IN ALL...IT IS CLOSE TO
 THE INTENSITY CONSENSUS AND INDICATES A MORE GRADUAL WEAKENING THAN
 HAS OCCURRED OVER THE PAST DAY OR TWO.  RICK IS STILL FORECAST TO
 BE A TROPICAL STORM AS IT MOVES NEAR SOUTHERN BAJA CALIFORNIA AND
 TOWARDS THE COAST OF MAINLAND MEXICO.
 
 RICK IS NOW MOVING NORTHWARD WITH AN INITIAL MOTION OF 350 DEGREES
 AT 7 KT.  THE TRACK GUIDANCE IS STILL IN GOOD AGREEMENT IN SHOWING
 A NORTH-NORTHEASTWARD TO NORTHEASTWARD TURN OVER THE NEXT 24 TO 36
 HOURS AS RICK GETS PICKED UP BY A SHORTWAVE TROUGH CURRENTLY ALONG
 THE WEST COAST OF THE UNITED STATES.  THE GUIDANCE ENVELOPE AND THE
 MODEL CONSENSUS TVCN HAVE SHIFTED JUST A LITTLE TO THE EAST AND
 CONTINUE TO SHOW THE CENTER OF RICK PASSING JUST TO THE SOUTHEAST OF
 THE SOUTHERN TIP OF BAJA CALIFORNIA.
  
 THE GOVERNMENT OF MEXICO HAS CHANGED THE HURRICANE WATCH FOR
 SOUTHERN BAJA CALIFORNIA TO A TROPICAL STORM WATCH DUE TO THE
 UPDATED INTENSITY FORECAST.
 
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      20/0300Z 19.1N 111.8W    60 KT
  12HR VT     20/1200Z 19.9N 111.6W    50 KT
  24HR VT     21/0000Z 21.3N 110.5W    50 KT
  36HR VT     21/1200Z 23.0N 108.8W    45 KT
  48HR VT     22/0000Z 24.8N 106.8W    30 KT...INLAND
  72HR VT     23/0000Z...DISSIPATED
  
 $$
 FORECASTER BERG/BROWN
  
 

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