107 
 WTPZ43 KNHC 312034
 TCDEP3
 HURRICANE JIMENA DISCUSSION NUMBER  13
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP132009
 200 PM PDT MON AUG 31 2009
  
 THE AIR FORCE RESERVE HURRICANE HUNTERS HAVE JUST COMPLETED THEIR
 MISSION IN JIMENA...AND FOUND THAT THE HURRICANE WAS STRONGER THAN
 PREVIOUSLY ESTIMATED. PEAK 700 MB FLIGHT-LEVEL WINDS WERE 149 KT
 AND THE MAXIMUM SFMR-MEASURED SURFACE WINDS WERE 132 KT OVER THE
 NORTHEAST QUADRANT. THE SFMR ALSO MEASURED 128 KT IN THE NORTHWEST
 EYEWALL AND 125 KT IN THE SOUTHWEST PART OF THE EYEWALL. A MINIMUM
 CENTRAL PRESSURE OF 931 MB WAS MEASURED BY DROPSONDE. THE CURRENT
 INTENSITY IS ADJUSTED UPWARD TO 135 KT...AT THE VERY HIGH END OF
 CATEGORY 4 STATUS. FLUCTUATIONS IN STRENGTH ARE LIKELY DURING THE
 NEXT DAY OR SO DUE TO INNER CORE EVENTS...PRIMARILY EYEWALL
 REPLACEMENTS. HOWEVER THE SHIPS MODEL INDICATES A GRADUAL DECREASE
 IN OCEANIC HEAT CONTENT AND SOME INCREASE IN WEST-SOUTHWESTERLY
 SHEAR DURING THE NEXT 36 HOURS. HOWEVER THESE ENVIRONMENTAL
 INFLUENCES SHOULD NOT PREVENT JIMENA FROM MAINTAINING MAJOR
 HURRICANE STRENGTH PRIOR TO LANDFALL. THE OFFICIAL INTENSITY
 FORECAST IS A BLEND OF THE SHIPS AND LGEM GUIDANCE.
  
 AFTER WOBBLING WEST-NORTHWESTWARD A FEW HOURS AGO...THE MOTION IS
 BACK TO NORTHWEST OR 315/9.  THERE HAS BEEN LITTLE CHANGE TO THE
 TRACK FORECAST PHILOSOPHY.  JIMENA IS LIKELY TO MOVE BETWEEN A
 MID-LEVEL RIDGE OVER NORTHWESTERN MEXICO AND A MID- TO UPPER-LEVEL
 CYCLONE JUST TO THE WEST OF THE BAJA PENINSULA.  THE U.K. MET.
 OFFICE GLOBAL MODEL...LIKE THE ECMWF GLOBAL MODEL...PREVIOUSLY
 WESTERN OUTLIERS...HAVE SHIFTED EASTWARD AND ARE NOW IN GENERAL
 AGREEMENT WITH THE OTHER DYNAMICAL MODELS.  HOWEVER THE U.K. AND
 ECMWF ARE STILL SOMEWHAT SLOWER THAN MOST OF THE GUIDANCE.  THE
 OFFICIAL FORECAST IS SIMILAR TO THE PREVIOUS ONE AND ABOUT IN THE
 MIDDLE OF THE DYNAMICAL TRACK MODEL SUITE.
 
 NO CHANGES TO THE WATCHES AND WARNINGS ARE NECESSARY AT THIS TIME.
 INTERESTS IN THE WARNING AREA SHOULD BE ADVISED THAT STRONG WINDS
 WILL PRECEDE THE ARRIVAL OF THE CENTER BY SEVERAL HOURS...SO
 PREPARATIONS NEED TO BE COMPLETED AS EARLY AS POSSIBLE. 
 ALSO...INTERESTS IN THE WARNING AREA ARE REMINDED...NOT TO FOCUS
 ON THE EXACT FORECAST TRACK.  A HURRICANE IS NOT A POINT...AND
 DANGEROUS IMPACTS EXTEND SOME DISTANCE FROM THE CENTER.  IN
 FACT...THE AIR FORCE RECONNAISSANCE OBSERVATIONS SHOW THAT JIMENA
 IS LARGER THAN PREVIOUS ESTIMATED.  MOREOVER...TRACK FORECAST
 ERRORS CAN EASILY BE 50 TO 75 MILES IN THE 24 TO 36 HOUR TIME
 FRAME.
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      31/2100Z 18.5N 109.2W   135 KT
  12HR VT     01/0600Z 19.6N 110.1W   130 KT
  24HR VT     01/1800Z 21.6N 111.1W   125 KT
  36HR VT     02/0600Z 23.6N 111.8W   115 KT
  48HR VT     02/1800Z 25.5N 112.2W    85 KT
  72HR VT     03/1800Z 27.8N 112.7W    50 KT...INLAND
  96HR VT     04/1800Z 29.5N 113.0W    50 KT...OVER WATER
 120HR VT     05/1800Z 31.0N 113.0W    30 KT...INLAND
  
 $$
 FORECASTER PASCH