523 
 WTPZ43 KNHC 292033
 TCDEP3
 HURRICANE JIMENA DISCUSSION NUMBER   5
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP132009
 200 PM PDT SAT AUG 29 2009
  
 VISIBLE SATELLITE IMAGES SHOW THAT JIMENA HAS A SMALL CENTRAL DENSE
 OVERCAST...ALONG WITH IMPRESSIVE BANDING FEATURES TO THE NORTH AND
 SOUTH OF THE CENTER. HOWEVER...DURING THE PAST COUPLE OF HOURS THE
 TINY EYE HAS BECOME LESS DISTINCT WITH SOME WARMING OF THE
 THUNDERSTORM CLOUD TOPS.  SATELLITE CLASSIFICATIONS HAVE BEEN
 PLAYING CATCH UP ALL DAY...NOW 90 KT FROM BOTH TAFB/SAB...AND THIS
 WILL BE THE INITIAL INTENSITY. THE ONLY FORESEEABLE WAY THAT JIMENA
 WOULD STOP INTENSIFYING DURING THE NEXT DAY OR SO IS AN EYEWALL
 CYCLE...WHICH IS A POSSIBILITY GIVEN THE SMALL EYE AND A MOAT OF
 DRIER AIR SEEN ON MICROWAVE IMAGERY.  OTHERWISE...ALL ENVIRONMENTAL
 CONDITIONS FAVOR THE DEVELOPMENT OF A POWERFUL CATEGORY FOUR
 HURRICANE DUE TO EXTREMELY WARM WATERS...AS MUCH AS 1.5C WARMER
 THAN AVERAGE...AND LOW SHEAR.  IT IS NOTABLE THAT JIMENA WILL BE
 TRAVERSING THE WARMEST WATERS IN THE BASIN OVER THE NEXT 48
 HOURS...WHICH HAVE BEEN UNTAPPED BY TROPICAL CYCLONES SO FAR THIS
 SEASON.  THE NHC FORECAST IS FAIRLY CLOSE TO A BLEND OF THE LGEM AND
 THE SHIPS MODEL...AND SHOWS ANOTHER RAPID INTENSIFICATION PERIOD
 DURING THE FIRST 24 HOURS.  WEAKENING SHOULD COMMENCE IN ABOUT
 2-3 DAYS DUE TO COOLING WATERS AND PERHAPS AN INCREASE IN SHEAR.
  
 THE FORMATION OF THE EYE HAS LED TO A MORE RELIABLE INITIAL MOTION
 OF 300/10...TO THE RIGHT OF THE PREVIOUS ESTIMATE.  A MOTION
 BETWEEN WEST-NORTHWEST AND NORTHWEST IS LIKELY FOR THE NEXT COUPLE
 OF DAYS AS THE HURRICANE IS STEERED AROUND THE SOUTHWESTERN PORTION
 OF A WEAK MID-LEVEL RIDGE OVER MEXICO.  THE HURRICANE AND GLOBAL
 MODELS ARE STILL IN A LARGE DISAGREEMENT OVER HOW MUCH A MID- TO
 UPPER-LEVEL TROUGH OVER BAJA CALIFORNIA WILL EFFECT JIMENA.  THE
 RIGHT SIDE OF THE GUIDANCE ENVELOPE CONSISTS OF THE GFDL/HWRF...
 WHICH INSISTS THAT JIMENA WILL TURN TO THE NORTH-NORTHWEST TOMORROW
 AND THREATEN BAJA CALIFORNIA OR WESTERN MEXICO. ALL OF THE OTHER
 GUIDANCE MAINTAIN ENOUGH OF A RIDGE BETWEEN THE TROUGH AND JIMENA
 TO CONTINUE A NORTHWESTWARD MOTION OF THE HURRICANE FOR SEVERAL
 DAYS...KEEPING JIMENA FARTHER AWAY FROM MEXICO.   ALTHOUGH THE
 HWRF/GFDL HAVE HISTORICALLY HAD AN EASTWARD BIAS FOR THESE TYPES OF
 SYSTEMS...THE GLOBAL MODELS HAVE GENERALLY MADE A SMALL EASTWARD
 ADJUSTMENT IN THEIR 1200 UTC FORECASTS.  THE NHC FORECAST IS
 SHIFTED A LITTLE TO THE RIGHT OF THE PREVIOUS ONE...BETWEEN THE
 MODEL CONSENSUS AND THE GLOBAL MODELS.  THIS FORECAST HAS TO BE
 CONSIDERED LOW CONFIDENCE DUE TO THE BIG DIFFERENCES BETWEEN THE
 HWRF/GFDL AND THE REST OF THE GUIDANCE. 
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      29/2100Z 15.1N 104.2W    90 KT
  12HR VT     30/0600Z 15.6N 105.3W   105 KT
  24HR VT     30/1800Z 16.3N 106.6W   120 KT
  36HR VT     31/0600Z 17.2N 107.8W   125 KT
  48HR VT     31/1800Z 18.3N 109.0W   125 KT
  72HR VT     01/1800Z 21.0N 111.5W   110 KT
  96HR VT     02/1800Z 24.0N 114.5W    80 KT
 120HR VT     03/1800Z 25.5N 118.0W    50 KT
  
 $$
 FORECASTER BLAKE