Hurricane JIMENA

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HURRICANE JIMENA DISCUSSION NUMBER   8
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP132009
800 AM PDT SUN AUG 30 2009

JIMENA HAS A SMALL EYE EMBEDDED WITHIN EXTREMELY COLD CLOUD TOPS. 
DVORAK T-NUMBERS ARE 6.0 FROM BOTH TAFB MIAMI AND SAB
WASHINGTON...WHICH EQUATES TO A CURRENT INTENSITY ESTIMATE OF 115
KT OR CATEGORY 4 INTENSITY.  THE HURRICANE IS EXPECTED TO REMAIN IN
AN ENVIRONMENT CONDUCIVE FOR STRENGTHENING FOR THE NEXT COUPLE OF
DAYS...SO THE INTENSITY CHANGE FOR THE NEXT 48 HOURS OR SO WILL
DEPEND LARGELY ON THE EVOLUTION OF THE INNER CORE...WHICH IS NOT
VERY PREDICTABLE.  NONETHELESS...SOME ADDITIONAL INCREASE IN
STRENGTH IS ANTICIPATED...AND THE OFFICIAL WIND SPEED FORECAST FOR
THE FIRST PART OF THE PERIOD IS FAIRLY SIMILAR TO THE SHIPS AND
GFDL GUIDANCE.  LATER IN THE FORECAST PERIOD THE GLOBAL MODELS
SUGGEST SOME INCREASE IN SOUTHWESTERLY SHEAR.  THIS...ALONG WITH
THE POSSIBLE INTERACTION WITH LAND...SHOULD CAUSE WEAKENING.  THE
OFFICIAL INTENSITY FORECAST FROM 72 TO 120 HOURS IS BASED ON A
MOTION NEAR AND OVER SOUTHERN BAJA CALIFORNIA.  HOWEVER SINCE THERE
IS CONSIDERABLE UNCERTAINTY IN THE TRACK FORECAST IN THE LATTER
PART OF THE PERIOD...THE 4 AND 5 DAY INTENSITIES ARE ALSO HIGHLY
UNCERTAIN.

THE FUTURE TRACK OF JIMENA APPEARS TO DEPEND ON TWO MAIN FACTORS...A
MID- TO UPPER-LEVEL LOW NEAR THE SOUTHERN BAJA CALIFORNIA PENINSULA
AND A MID-LEVEL RIDGE OVER THE SOUTHWESTERN U.S. AND NORTHWESTERN
MEXICO.  THE GLOBAL MODELS SHOW THE LOW DRIFTING WESTWARD AND
WEAKENING WITH THE RIDGE BUILDING WESTWARD...WHEREAS THE HWRF AND
GFDL DO NOT WEAKEN THE LOW OR BUILD THE RIDGE AS MUCH. 
CONSEQUENTLY THE GFDL/HWRF TAKE JIMENA BETWEEN THE LOW AND THE
RIDGE...AND OVER BAJA OR MAINLAND MEXICO WHILE THE GLOBAL MODELS
PREDICT JIMENA TO MOVE TO THE WEST OF BAJA.  AS A COMPROMISE...THE
OFFICIAL FORECAST LIES BETWEEN THESE TWO POSSIBLE SCENARIOS AND
MOVES THE TROPICAL CYCLONE NEAR THE SOUTHWEST COAST OF THE BAJA
PENINSULA.

INTEREST IN WESTERN MAINLAND MEXICO AND SOUTHERN BAJA CALIFORNIA
SHOULD MONITOR THE PROGRESS OF JIMENA.  A HURRICANE WATCH MAY BE
REQUIRED FOR PORTIONS OF SOUTHERN BAJA LATER TODAY.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      30/1500Z 16.3N 106.3W   115 KT
 12HR VT     31/0000Z 17.1N 107.1W   120 KT
 24HR VT     31/1200Z 18.4N 108.3W   125 KT
 36HR VT     01/0000Z 20.0N 109.4W   125 KT
 48HR VT     01/1200Z 21.7N 110.4W   125 KT
 72HR VT     02/1200Z 25.0N 112.0W    90 KT...INLAND
 96HR VT     03/1200Z 27.0N 113.0W    60 KT...INLAND
120HR VT     04/1200Z 28.0N 114.0W    30 KT...INLAND
 
$$
FORECASTER PASCH
 
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