016 
 WTPZ45 KNHC 180839
 TCDEP5
 HURRICANE RICK DISCUSSION NUMBER  12
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP202009
 200 AM PDT SUN OCT 18 2009
 
 INFRARED SATELLITE IMAGES SHOW THAT RICK IS MAINTAINING AN EXTREMELY
 WELL-DEFINED 15 N MI DIAMETER EYE EMBEDDED WITHIN VERY COLD CLOUD
 TOPS.  THE UPPER-TROPOSPHERIC OUTFLOW IS QUITE EXTENSIVE AS WELL. 
 BOTH OBJECTIVE AND SUBJECTIVE DVORAK T-NUMBERS ARE CLOSE TO 7.5
 WHICH CONTINUE TO SUPPORT AN INTENSITY OF ABOUT 155 KT...I.E.
 CATEGORY FIVE STRENGTH.  MICROWAVE IMAGERY SUGGESTS THAT A
 CONCENTRIC EYEWALL MAY BE TRYING TO FORM WHICH COULD PRESAGE AN
 EYEWALL REPLACEMENT...AND POSSIBLY SOME WEAKENING.  IN ANY EVENT...
 RICK HAS PROBABLY REACHED ITS MAXIMUM INTENSITY AS IT WILL BE
 MOVING INTO AN ENVIRONMENT THAT WILL GRADUALLY BECOME LESS
 CONDUCIVE FOR STRENGTHENING.  ALTHOUGH SEA SURFACE TEMPERATURES
 SHOULD BECOME ONLY SLIGHTLY COOLER ALONG THE TRACK OF RICK...GLOBAL
 MODEL FORECASTS INDICATE A GRADUAL INCREASE IN VERTICAL SHEAR.  THE
 SHIPS MODEL SHOWS SOUTHWESTERLY SHEAR OF 20-30 KT IN ITS 3-5 DAY
 PREDICTION.  THE OFFICIAL INTENSITY FORECAST IS BETWEEN THE SHIPS
 AND LGEM GUIDANCE THROUGH 48 HOURS AND SOMEWHAT ABOVE THOSE MODELS
 AND THE INTENSITY MODEL CONSENSUS THEREAFTER...TO ALLOW FOR THE
 POSSIBILITY THAT THE HURRICANE WILL NOT BE AFFECTED SO MUCH BY THE
 SHEAR. 
 
 THE INITIAL MOTION...285/12...CONTINUES ABOUT THE SAME AS BEFORE. 
 THERE ARE NO IMPORTANT CHANGES TO THE TRACK FORECAST SCENARIO. 
 RICK IS BEING STEERED BY THE FLOW TO THE SOUTH OF A WEAKENING
 SUBTROPICAL RIDGE.  A BREAK IN THE RIDGE...ASSOCIATED WITH A
 MID-TROPOSPHERIC TROUGH MOVING OVER CALIFORNIA IN A DAY OR
 TWO...SHOULD CAUSE THE HURRICANE TO GRADUALLY TURN TOWARD THE NORTH
 OVER THE NEXT 48-72 HOURS.  AFTERWARDS...THE TRACK MODELS ARE IN
 REASONABLY GOOD AGREEMENT THAT RICK WILL TURN NORTH-NORTHEASTWARD
 AND NORTHEASTWARD.  THE U.K. MET OFFICE MODEL REMAINS THE OUTLIER
 OF THE DYNAMICAL GUIDANCE IN THAT IT SHOWS LITTLE MOTION BEYOND 48
 HOURS AND IS WELL TO THE SOUTHWEST OF THE MODEL CONSENSUS.  THE NHC
 FORECAST TRACK IS VERY SIMILAR TO THE PREVIOUS ONE...AND SHOWS A
 TRACK OVER SOUTHERN BAJA AND WESTERN MAINLAND MEXICO IN THE LATTER
 PART OF THE PERIOD.  HOWEVER INTERESTS IN THESE AREAS SHOULD BEAR
 IN MIND THAT SIGNIFICANT ERRORS IN LANDFALL LOCATION AND TIMING ARE
 POSSIBLE IN THE 4- AND 5-DAY TIME FRAME.  
 
 ALTHOUGH THE HURRICANE IS NOT LIKELY TO MAINTAIN CATEGORY FIVE
 STRENGTH WHEN IT APPROACHES BAJA CALIFORNIA...IT COULD STILL BE
 QUITE POWERFUL BY THAT TIME.  INTERESTS IN THAT AREA AND ALONG THE
 SOUTHWEST COAST OF MAINLAND MEXICO SHOULD CLOSELY FOLLOW THE
 PROGRESS OF THIS EXTREMELY DANGEROUS HURRICANE OVER THE NEXT
 SEVERAL DAYS.
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      18/0900Z 15.3N 107.2W   155 KT
  12HR VT     18/1800Z 15.9N 109.0W   150 KT
  24HR VT     19/0600Z 17.0N 110.7W   140 KT
  36HR VT     19/1800Z 18.0N 111.7W   130 KT
  48HR VT     20/0600Z 19.1N 112.0W   115 KT
  72HR VT     21/0600Z 21.5N 111.0W    95 KT
  96HR VT     22/0600Z 24.5N 109.0W    75 KT
 120HR VT     23/0600Z 28.0N 104.0W    25 KT...DISSIPATING INLAND
  
 $$
 FORECASTER PASCH