000 WTPZ43 KNHC 012051 TCDEP3 HURRICANE JIMENA DISCUSSION NUMBER 17 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP132009 200 PM PDT TUE SEP 01 2009 EARLIER DATA FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INDICATED THAT JIMENA WAS COMPLETING ITS EYEWALL REPLACEMENT CYCLE...WITH THE INNER EYE DISSIPATING AND THE NEW EYE ABOUT 25-30 N MI ACROSS. THE AIRCRAFT DATA SUGGEST AN INTENSITY NEAR 115 KT AT THAT TIME. SINCE THEN...THE CLOUD TOPS NEAR THE CENTER HAVE WARMED AND THE EYE HAS NOT CLEARED OUT. BASED ON THIS...IT IS ESTIMATED THAT JIMENA HAS WEAKENED A LITTLE MORE...AND THE INITIAL INTENSITY IS REDUCED TO 110 KT. THE INITIAL MOTION IS 330/10. JIMENA IS FORECAST TO CONTINUE IN A GENERAL NORTH-NORTHWESTERLY DIRECTION DURING THE NEXT COUPLE OF DAYS BETWEEN A MID/UPPER-LEVEL LOW WEST OF THE BAJA PENINSULA AND A MID-LEVEL RIDGE OVER NORTHERN MEXICO...WITH ALL THE TRACK GUIDANCE REMAINING IN AGREEMENT WITH THIS SCENARIO. THE FORECAST BECOMES LESS CONFIDENT FROM 72 HR ON DUE TO A LARGE SPREAD IN THE GUIDANCE. THE GFDL AND GFDN STILL CALL FOR JIMENA TO TURN NORTHEASTWARD ACROSS NORTHWESTERN MEXICO AND THE SOUTHWESTERN UNITED STATES. THE REST OF THE DYNAMICAL GUIDANCE EITHER STALLS THE CYCLONE OVER CENTRAL BAJA CALIFORNIA OR TURNS IT WESTWARD INTO THE PACIFIC. THIS APPEARS TO BE DUE TO HIGHER PRESSURES DEVELOPING NORTH OF THE CYCLONE...AND THE SYSTEM SHEARING APART AS STRONG UPPER-LEVEL WESTERLY FLOW DEVELOPS. THE NEW FORECAST TRACK IS AN UPDATE OF THE PREVIOUS THROUGH THROUGH 72 HR...AND THEN IS SLOWER THAN THE PREVIOUS TRACK THEREAFTER. THE NEW TRACK IS JUST RIGHT OF THE CENTER OF THE DYNAMICAL GUIDANCE THROUGH 72 HR...AND CLOSE TO THE MODEL CONSENSUS THEREAFTER. THE NEW TRACK CALLS FOR LANDFALL ON THE CENTRAL BAJA CALIFORNIA PENINSULA IN ABOUT 36 HR. IT NOW APPEARS UNLIKELY THAT THERE WILL BE NOTABLE INTENSIFICATION AT THE END OF THE EYEWALL REPLACEMENT CYCLE...AS JIMENA IS STARTING TO MOVE OVER COOLER SEA SURFACE TEMPERATURES. A FASTER WEAKENING SHOULD OCCUR AFTER LANDFALL...AND AN EVEN FASTER WEAKENING SHOULD OCCUR WITH THE ONSET OF STRONG WESTERLY VERTICAL SHEAR IN ABOUT 72 HR. THE NEW INTENSITY FORECAST IS SIGNIFICANTLY LOWER THAN THAT OF THE PREVIOUS ADVISORY...AND THERE IS A CHANCE THAT JIMENA COULD WEAKEN MORE THAN FORECAST AFTER LANDFALL. 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. THE FORECAST TRACK OF JIMENA IS ALMOST PARALLEL TO THE COAST OF BAJA CALIFORNIA...AND SMALL DEVIATIONS LEFT OR RIGHT OF THE TRACK COULD RESULT IN LARGE ERRORS IN BOTH THE LOCATION AND TIMING OF LANDFALL. FORECAST POSITIONS AND MAX WINDS INITIAL 01/2100Z 21.9N 111.2W 110 KT 12HR VT 02/0600Z 23.3N 112.0W 105 KT 24HR VT 02/1800Z 25.2N 112.7W 95 KT 36HR VT 03/0600Z 26.5N 113.1W 85 KT 48HR VT 03/1800Z 27.6N 113.4W 55 KT...INLAND 72HR VT 04/1800Z 28.5N 113.5W 35 KT...INLAND 96HR VT 05/1800Z 29.5N 113.5W 25 KT...OVER WATER 120HR VT 06/1800Z 30.5N 113.5W 20 KT...REMNANT LOW $$ FORECASTER BEVEN