000 WTPZ43 KNHC 300241 TCDEP3 HURRICANE JIMENA DISCUSSION NUMBER 6 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP132009 800 PM PDT SAT AUG 29 2009 WHILE THE SMALL EYE SEEN EARLIER IN VISIBLE AND INFRARED IMAGERY IS NOT APPARENT AT THIS TIME...SSM/I DATA AT 0106 UTC SHOWS IT IS STILL PRESENT UNDER THE CENTRAL DENSE OVERCAST. THE MICROWAVE DATA ALSO SHOWED AN OUTER BAND WRAPPING AROUND THE CENTRAL CONVECTION THAT MAY BE THE PRECURSOR OF AN OUTER EYEWALL. SINCE THE EYE IS NOT APPARENT IN CONVENTIONAL IMAGERY...IT IS UNCLEAR IF THE HURRICANE IS STILL INTENSIFYING. THUS...THE INITIAL INTENSITY REMAINS 90 KT IN AGREEMENT WITH SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB. HOWEVER...THIS COULD BE CONSERVATIVE. JIMENA HAS TURNED A LITTLE BIT TO THE RIGHT...WITH THE INITIAL MOTION NOW 305/10. THE HURRICANE IS ON THE SOUTHWEST SIDE OF A DEEP-LAYER RIDGE OVER CENTRAL MEXICO...WITH WATER VAPOR IMAGERY SHOWING A MID/UPPER-LEVEL LOW OVER THE GULF OF CALIFORNIA NEAR 27N111W. THE GLOBAL MODELS FORECAST THE MEXICAN RIDGE TO BUILD NORTHWESTWARD AND PUSH THE WEAKENING LOW INTO THE PACIFIC...WHICH WOULD ALLOW JIMENA TO CONTINUE ON A GENERALLY NORTHWESTWARD TRACK FOR THE NEXT SEVERAL DAYS. ON THE OTHER HAND...THE GFDL AND HWRF KEEP THE LOW STRONG ENOUGH AND FAR ENOUGH TO THE EAST TO TURN JIMENA NORTHWARD WITH A LANDFALL IN WESTERN MEXICO. AT THIS TIME...IT IS DIFFICULT TO DETERMINE WHICH SCENARIO WILL PLAY OUT. HOWEVER...THE GFDL HAS PERFORMED WELL IN SIMILAR PAST SITUATIONS AND THUS CANNOT BE RULED OUT. ALSO...MANY OF THE GLOBAL MODELS FORECAST JIMENA TO SHEAR APART IN THE LATER PART OF THE FORECAST PERIOD...WHICH MAY NOT HAPPEN TO SUCH A STRONG AND DEEP HURRICANE. THE GUIDANCE ENVELOPE HAS SHIFTED TO THE EAST SINCE THE PREVIOUS ADVISORY...AND BASED ON THIS AND THE CURRENT MOTION THE NEW FORECAST TRACK IS SHIFTED TO THE EAST AS WELL. THE NEW TRACK IS NEAR THE THE GUNA...TVCN...AND TVCC CONSENSUS MODELS...AS WELL AS NEAR THE GFS DYNAMICAL MODEL. CONDITIONS APPEAR FAVORABLE FOR SIGNIFICANT STRENGTHENING DURING THE NEXT 48 HR...AS JIMENA WILL BE OVER VERY WARM SEA SURFACE TEMPERATURES IN A LIGHT VERTICAL WIND SHEAR ENVIRONMENT. THE ONLY POTENTIAL LIMITING FACTOR AT THE MOMENT IS THE POSSIBILITY OF EYEWALL REPLACEMENT CYCLES. ALL GUIDANCE FORECASTS THE SYSTEM TO BECOME A MAJOR HURRICANE DURING THIS TIME...AND THE NEW INTENSITY FORECAST FOLLOWS THAT WITH A PEAK INTENSITY OF 125 KT IN 36 HR. IT IS POSSIBLE DEPENDING ON THE TIMING OF THE EYEWALL REPLACEMENT CYCLES THAT JIMENA COULD GET STRONGER THAN THAT. ON THE FORECAST TRACK...JIMENA WOULD REACH COOLER SSTS AFTER 48 HR...WHICH SHOULD CAUSE THE STORM TO WEAKEN. THE LONGER-TERM INTENSITY FORECAST IS LOW CONFIDENCE...AS THE POSSIBILITY OF LAND INTERACTION AND INCREASED VERTICAL WIND SHEAR AFTER 72 HR MAKE THE FORECAST MORE PROBLEMATIC. THE GFDL AND HWRF MODELS FORECAST WINDS NEAR HURRICANE FORCE AT CABO CORRIENTES IN ABOUT 36 HR...AND IF THESE MODEL FORECASTS APPEAR TO BE VERIFYING WATCHES OR WARNING COULD BE NEEDED LATER TONIGHT OR SUNDAY. IN ADDITION...THE NEW FORECAST TRACK INCREASES THE THREAT TO THE SOUTHERN BAJA CALIFORNIA PENINSULA. INTERESTS IN SOUTHERN BAJA AND WESTERN MEXICO SHOULD MONITOR THE PROGRESS OF JIMENA. FORECAST POSITIONS AND MAX WINDS INITIAL 30/0300Z 15.8N 105.1W 90 KT 12HR VT 30/1200Z 16.5N 106.2W 105 KT 24HR VT 31/0000Z 17.3N 107.4W 120 KT 36HR VT 31/1200Z 18.2N 108.4W 125 KT 48HR VT 01/0000Z 19.5N 109.6W 125 KT 72HR VT 02/0000Z 22.5N 112.0W 110 KT 96HR VT 03/0000Z 25.0N 114.0W 75 KT 120HR VT 04/0000Z 26.5N 117.0W 45 KT $$ FORECASTER BEVEN