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Hurricane JIMENA


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HURRICANE JIMENA DISCUSSION NUMBER  10...CORRECTED
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP132009
800 PM PDT SUN AUG 30 2009

CORRECTED FOR DISCUSSION OF WIND SPEED PROBABILITIES

THE STRUCTURE OF JIMENA CONTINUES TO BE CHARACTERIZED BY A SMALL EYE
EMBEDDED WITHIN A SYMMETRIC CENTRAL DENSE OVERCAST. OUTFLOW IS
EXCELLENT IN ALL QUADRANTS...AND TOPS WITHIN THE CDO HAVE CONTINUED
TO COOL. DVORAK CI-NUMBERS WERE 6.5 FROM TAFB AND 6.0 FROM SAB AT
0000 UTC...AND OBJECTIVE DVORAK CI-NUMBERS HAVE BEEN NEAR 6.5 FOR
SEVERAL HOURS. BASED ON THE INCREASING TREND IN THE SATELLITE
ESTIMATES...THE INITIAL INTENSITY IS RAISED TO 125 KT. CONTINUED
STRENGTHENING IS POSSIBLE OVER THE NEXT 24 HOURS...AS JIMENA WILL
BE IN AN IDEAL ENVIRONMENT FOR INTENSIFICATION. HOWEVER...IF AN
EYEWALL REPLACEMENT CYCLE OCCURS IT WOULD LIKELY HALT ANY
INTENSIFICATION...AT LEAST TEMPORARILY. GIVEN THE LIMITED
PREDICTABILITY OF THESE INNER-CORE CHANGES...THE OFFICIAL FORECAST
SHOWS A SLIGHT INCREASE IN INTENSITY IN THE SHORT-TERM. AROUND 48
HOURS...INCREASING WESTERLY VERTICAL WIND SHEAR AND INTERACTION
WITH LAND SHOULD CAUSE JIMENA TO WEAKEN. THE UNCERTAINTY IN THE
TRACK...AND HOW MUCH THE CYCLONE INTERACTS WITH LAND...INTRODUCES
ADDITIONAL UNCERTAINTY INTO THE INTENSITY FORECAST LATER IN THE
PERIOD. 
 
JIMENA HAS CONTINUED TO EXHIBIT TROCHOIDAL WOBBLES FOR THE PAST FEW
HOURS. THE SMOOTHED INITIAL MOTION ESTIMATE IS 305/06...A LITTLE TO
THE RIGHT OF THE PREVIOUS ADVISORY. THE INTERACTION BETWEEN JIMENA
AND A MID- TO UPPER-LEVEL LOW CENTERED NEAR 24N 112W WILL BE
CRITICAL TO THE EVENTUAL TRACK OF THE HURRICANE. THE MID- TO
UPPER-LEVEL LOW WILL MOVE SLOWLY WESTWARD THROUGH THE FORECAST
PERIOD...AND THE GFS...NOGAPS...GFDL...GFDN...AND HWRF SUGGEST THAT
IT WILL REMAIN STRONG ENOUGH TO PULL JIMENA NORTHWARD TOWARD THE
BAJA CALIFORNIA PENINSULA. ANOTHER GROUP OF MODELS...INCLUDING THE
ECMWF...UKMET...AND CANADIAN WEAKEN THE MID- TO UPPER-LEVEL LOW AND
TURN JIMENA TOWARD THE WEST AS THE SUBTROPICAL RIDGE BUILDS NORTH
OF THE CYCLONE. THE HIGHER-RESOLUTION 1800 UTC GFS PARALLEL
ENSEMBLE MEAN SUPPORTS THE MORE EASTWARD TRACK SCENARIO...WHILE THE
1200 UTC ECMWF ENSEMBLE MEAN SHOWS A MORE WESTERLY TRACK.
HOWEVER...THERE IS LARGE SPREAD IN THE SEA-LEVEL PRESSURE FIELD
NORTH OF THE ECMWF ENSEMBLE MEAN POSITION...SUGGESTING THAT A
SIGNIFICANT NUMBER OF THE MEMBERS HAVE A TRACK CLOSER TO BAJA. THE
MULTI-MODEL TRACK CONSENSUS CONTINUES TO FAVOR THE MORE EASTWARD
SCENARIO...AND SO DOES THE OFFICIAL FORECAST...WHICH HAS BEEN
SHIFTED SLIGHTLY TO THE EAST FOR THIS PACKAGE. 

BASED ON THE OFFICIAL FORECAST...THE ISSUANCE OF A HURRICANE WATCH
IS REQUIRED FOR THE SOUTHERN PORTION OF THE BAJA CALIFORNIA
PENINSULA AT THIS TIME. JIMENA IS EXPECTED TO BE A VERY DANGEROUS
HURRICANE NEAR THE SOUTHERN BAJA PENINSULA IN 36 TO 48 HOURS. THE
WIND SPEED PROBABILITY PRODUCT INDICATES THAT THERE IS CURRENTLY A
20 TO 30 PERCENT CHANCE OF HURRICANE-FORCE WINDS OCCURRING AT ANY
INDIVIDUAL POINT LOCATION OVER THE BAJA PENINSULA SOUTH OF A LINE
FROM LORETO TO PUERTO SAN ANDRESITO. 

INTERESTS IN WESTERN MAINLAND MEXICO AND ELSEWHERE IN CENTRAL AND
SOUTHERN BAJA CALIFORNIA SHOULD CONTINUE TO MONITOR THE PROGRESS OF
JIMENA. ADDITIONAL WATCHES MAY BE REQUIRED FOR PORTIONS OF THESE
AREAS TONIGHT OR MONDAY.  
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      31/0300Z 17.0N 107.2W   125 KT
 12HR VT     31/1200Z 17.8N 108.0W   130 KT
 24HR VT     01/0000Z 19.2N 109.1W   130 KT
 36HR VT     01/1200Z 21.3N 110.2W   125 KT
 48HR VT     02/0000Z 23.4N 111.0W   120 KT
 72HR VT     03/0000Z 27.0N 112.5W    65 KT...INLAND
 96HR VT     04/0000Z 28.6N 113.5W    40 KT...INLAND
120HR VT     05/0000Z 29.0N 115.0W    25 KT
 
$$
FORECASTER BRENNAN
 
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