000
WTPZ43 KNHC 010849
TCDEP3
HURRICANE JIMENA DISCUSSION NUMBER  15
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP132009
200 AM PDT TUE SEP 01 2009
 
THE SMALL EYE OF JIMENA BECAME LESS DISTINCT IN SATELLITE IMAGERY
AROUND 0500 UTC...HOWEVER SINCE THAT TIME IT HAS WARMED AND IS
EMBEDDED WITHIN VERY COLD CLOUD TOPS AND A RATHER SYMMETRIC CDO.
THE LATEST DVORAK CI-NUMBERS REMAIN 6.5 FROM TAFB AND 6.0 FROM
SAB...AND OBJECTIVE ADT ESTIMATES ALSO CONTINUE TO HOVER AROUND
T6.5. BASED ON THE SATELLITE APPEARANCE AND UNCHANGED SATELLITE
ESTIMATES...THE INITIAL INTENSITY WILL REMAIN 135 KT FOR THIS
ADVISORY.  AN AIR FORCE HURRICANE HUNTER AIRCRAFT IS SCHEDULED TO
INVESTIGATE JIMENA AROUND 1500 UTC THIS MORNING.  THE HURRICANE
WILL BE MOVING OVER LOWER OCEAN HEAT CONTENT...HOWEVER VERTICAL
WIND SHEAR IS FORECAST TO REMAIN LOW...SO ONLY GRADUAL WEAKENING IS
SHOWN DURING THE NEXT 24 HOURS.  JIMENA IS EXPECTED TO REMAIN A
MAJOR HURRICANE AS IT NEARS THE BAJA PENINSULA.  THEREAFTER...
LAND INTERACTION AND INCREASING WESTERLY SHEAR SHOULD INDUCE A
FASTER RATE OF WEAKENING.  THE CURRENT FORECAST ASSUMES THAT JIMENA
WILL REMAIN A TROPICAL CYCLONE WHEN IT EMERGES INTO THE GULF OF
CALIFORNIA IN A FEW DAYS.

THE INITIAL MOTION ESTIMATE IS 330/10. JIMENA IS FORECAST TO
CONTINUE IN A NORTH-NORTHWESTERLY DIRECTION DURING THE NEXT COUPLE
OF DAYS BETWEEN A MID- TO UPPER-LEVEL LOW WEST OF THE BAJA
PENINSULA AND A MID-LEVEL RIDGE OVER NORTHERN MEXICO. THE LATEST
TRACK GUIDANCE ENVELOPE HAS SHIFTED A LITTLE WESTWARD. THE GFS AND
UKMET MODELS ARE ON THE LEFT SIDE OF THE MODEL SUITE WHILE THE
GFDL...HWRF AND ECMWF ARE ALONG THE RIGHT SIDE. THE SHIFT IN THE
GUIDANCE IS NOT ENOUGH TO WARRANT A SIGNIFICANT CHANGE FROM THE
PREVIOUS NHC ADVISORY...AND THE NEW TRACK LIES ALONG THE RIGHT SIDE
OF THE MODEL ENVELOPE.  
  
BASED ON THE NEW FORECAST TRACK...THE GOVERNMENT OF MEXICO HAS
EXTENDED THE HURRICANE WARNING NORTHWARD ALONG BOTH COASTS OF THE
BAJA PENINSULA.  ADDITIONAL WATCHES AND WARNINGS MAY BE REQUIRED
LATER TODAY.
 
INTERESTS IN THE HURRICANE WARNING AREA ARE ADVISED THAT STRONG
WINDS WILL PRECEDE THE ARRIVAL OF THE CENTER BY SEVERAL HOURS...SO
PREPARATIONS NEED TO BE COMPLETED VERY SOON. REMEMBER NOT TO FOCUS
ON THE EXACT FORECAST TRACK SINCE DANGEROUS IMPACTS EXTEND SOME
DISTANCE FROM THE CENTER. JIMENA WILL BE APPROACHING THE BAJA
PENINSULA AT AN OBLIQUE ANGLE...AND SMALL DEVIATIONS LEFT OR RIGHT
OF THE FORECAST TRACK COULD RESULT IN LARGE ERRORS IN BOTH THE
LOCATION AND TIMING OF LANDFALL.
  
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      01/0900Z 20.2N 110.1W   135 KT
 12HR VT     01/1800Z 21.6N 110.8W   130 KT
 24HR VT     02/0600Z 23.5N 111.6W   120 KT
 36HR VT     02/1800Z 25.2N 112.3W   100 KT
 48HR VT     03/0600Z 26.7N 112.7W    75 KT...INLAND
 72HR VT     04/0600Z 28.4N 113.1W    50 KT...INLAND
 96HR VT     05/0600Z 30.0N 113.0W    45 KT...OVER WATER
120HR VT     06/0600Z 31.5N 112.5W    30 KT...INLAND
 
$$
FORECASTER BROWN