Hurricane JIMENA

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HURRICANE JIMENA DISCUSSION NUMBER  11
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP132009
200 AM PDT MON AUG 31 2009
 
THE SMALL EYE OF JIMENA HAS BECOME A LITTLE LESS DISTINCT IN
INFRARED SATELLITE IMAGERY.  AN EARLIER SSMIS MICROWAVE OVERPASS
ALSO SHOWED A SOMEWHAT LESS DEFINED EYE...BUT WITH A WELL-DEFINED
OUTER BAND.  THIS MAY BE A SIGN THAT AN EYE-WALL REPLACEMENT HAS
STARTED...HOWEVER THERE HAVE BEEN NO RECENT MICROWAVE IMAGES TO
CORROBORATE THIS.  DUE TO THE RECENT SATELLITE TRENDS...DVORAK
DATA-T NUMBER HAVE DECREASED SLIGHTLY...BUT A BLEND OF THE
OBJECTIVE AND SUBJECTIVE CURRENT INTENSITY ESTIMATES SUGGESTS
MAINTAINING AN INITIAL INTENSITY OF 125 KT.
 
JIMENA IS MOVING NORTHWESTWARD OR 310/7 KT.  A MID-LEVEL RIDGE
OVER MEXICO AND AN UPPER-LEVEL LOW NEAR THE WEST COAST OF THE
CENTRAL BAJA PENINSULA ARE THE FEATURES THAT WILL PLAY A
ROLE IN STEERING THE HURRICANE.  THE 0000 UTC MODELS HAVE COME INTO
BETTER AGREEMENT ON THE FUTURE TRACK OF JIMENA.  NEARLY ALL OF THE
MODELS KEEP THE UPPER-LOW INTACT LONG ENOUGH TO TURN THE HURRICANE
NORTH-NORTHWESTWARD.  THE OUTLIER TO THIS SOLUTION IS THE UKMET
WHICH CONTINUES TO SHOW A WEST-NORTHWESTWARD MOTION.  THE CANADIAN
AND ECMWF MODELS HAVE SHIFTED EASTWARD AND ARE NOW IN MUCH BETTER
AGREEMENT WITH THE REMAINDER OF THE GUIDANCE IN PREDICTING A TRACK
NEAR OR OVER THE BAJA PENINSULA IN A COUPLE OF DAYS.  THE NEW NHC
TRACK FORECAST IS ESSENTIALLY AN UPDATE TO THE PREVIOUS ADVISORY...
AND IS NEAR THE MULTI-MODEL CONSENSUS.
 
THE HURRICANE IS EXPECTED TO REMAIN OVER VERY WARM WATER AND IN A
LOW SHEAR ENVIRONMENT DURING THE NEXT 24 HOURS.  THE OFFICIAL
FORECAST SHOWS LITTLE CHANGE IN STRENGTH DURING THAT TIME...HOWEVER
FLUCTUATIONS COULD OCCUR AS THE RESULT OF AN EYEWALL REPLACEMENT.
IN ABOUT 48 HOURS...WESTERLY SHEAR IS FORECAST TO INCREASE.  THAT
COMBINED WITH POSSIBLE LAND INTERACTION SHOULD BEGIN TO WEAKEN
THE HURRICANE.  THE OFFICIAL INTENSITY FORECAST IS A BLEND OF THE
AVAILABLE GUIDANCE AND INDICATES THAT JIMENA COULD REMAIN A VERY
DANGEROUS HURRICANE AS IT MOVES NEAR THE SOUTHERN BAJA PENINSULA.
 
BASED ON THE CURRENT FORECAST...A HURRICANE WARNING MAY BE REQUIRED
LATER THIS MORNING FOR A PORTION OF THE SOUTHERN BAJA PENINSULA.
INTERESTS ELSEWHERE IN CENTRAL AND SOUTHERN BAJA CALIFORNIA AND THE
WESTERN PORTION OF MAINLAND MEXICO SHOULD CONTINUE TO MONITOR THE
PROGRESS OF JIMENA.  ADDITIONAL WATCHES OR WARNINGS MAY BE REQUIRED
FOR PORTIONS OF THESE AREAS LATER TODAY.
 
A U.S. AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT IS SCHEDULED TO
INVESTIGATE JIMENA AROUND 1800 UTC TODAY.  DATA FROM THE AIRCRAFT
SHOULD PROVIDE A BETTER ASSESSMENT OF THE INTENSITY AND SIZE OF THE
HURRICANE.
  
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      31/0900Z 17.5N 107.9W   125 KT
 12HR VT     31/1800Z 18.5N 108.7W   125 KT
 24HR VT     01/0600Z 20.1N 109.8W   125 KT
 36HR VT     01/1800Z 22.1N 110.8W   115 KT
 48HR VT     02/0600Z 24.1N 111.5W   100 KT
 72HR VT     03/0600Z 27.2N 112.7W    50 KT...INLAND
 96HR VT     04/0600Z 28.5N 113.3W    30 KT...INLAND
120HR VT     05/0600Z 29.5N 114.0W    25 KT...REMNANT LOW
 
$$
FORECASTER BROWN
 
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