000 WTPZ43 KNHC 301437 TCDEP3 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