000 WTPZ43 KNHC 010249 TCDEP3 HURRICANE JIMENA DISCUSSION NUMBER 14 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP132009 800 PM PDT MON AUG 31 2009 SINCE THE DEPARTURE OF THE HURRICANE HUNTER AIRCRAFT THIS AFTERNOON...THE SATELLITE PRESENTATION OF JIMENA HAS REMAINED IMPRESSIVE...WITH A SMALL EYE EMBEDDED WITHIN VERY COLD CLOUD TOPS IN A LARGE CDO. DVORAK CI-NUMBERS AT 0000 UTC WERE 6.5 FROM TAFB AND 6.0 FROM SAB AND THE ADT HAS BEEN SHOWING T-NUMBERS OF 6.5 FOR THE LAST SEVERAL HOURS. BASED ON THE CONTINUED IMPRESSIVE SATELLITE APPEARANCE...THE INITIAL INTENSITY IS HELD AT 135 KT FOR THIS ADVISORY...BUT IT IS POSSIBLE THAT JIMENA COULD HAVE REACHED CATEGORY 5 STATUS EARLIER TODAY. THE INTENSITY FORECAST IS HELD STEADY FOR 12 HOURS...AND THEN A SLOW WEAKENING TREND IS INDICATED AS JIMENA WILL BE MOVING OVER LOWER OCEAN HEAT CONTENT AS THE CYCLONE APPROACHES THE BAJA PENINSULA. HOWEVER...JIMENA IS EXPECTED TO REMAIN A MAJOR HURRICANE UNTIL LANDFALL. MORE SUBSTANTIAL WEAKENING IS EXPECTED AS JIMENA INTERACTS WITH THE BAJA PENINSULA...AND THE INTENSITY FORECAST LATE IN THE PERIOD ASSUMES THAT JIMENA WILL STILL BE A TROPICAL CYCLONE WHEN IT EMERGES INTO THE GULF OF CALIFORNIA IN ABOUT 3 DAYS. THE INITIAL MOTION ESTIMATE IS 320/08. THE TRACK FORECAST PHILOSOPHY REMAINS UNCHANGED...AS JIMENA IS BEING STEERED BY A MID- TO UPPER-LEVEL LOW WEST OF THE BAJA PENINSULA AND THE SUBTROPICAL RIDGE CENTERED OVER NORTHWESTERN MEXICO. THE TRACK MODEL GUIDANCE IS IN GOOD AGREEMENT ON TURNING JIMENA TOWARD THE NORTH-NORTHWEST AND THEN TOWARD THE NORTH AS IT APPROACHES THE BAJA PENINSULA. THE OFFICIAL FORECAST IS CLOSE TO THE MULTI-MODEL CONSENSUS TVCN...AND IS SLIGHTLY TO THE RIGHT OF THE PREVIOUS PACKAGE THROUGH 36 HOURS. BEYOND THAT TIME...THE NEW FORECAST IS SIMPLY AN UPDATE OF THE PREVIOUS ONE. IT IS NOW NECESSARY TO EXTEND HURRICANE WATCHES FARTHER NORTH ALONG BOTH COASTS OF THE BAJA PENINSULA...AND TO ISSUE A TROPICAL STORM WATCH FOR A PORTION OF THE WEST COAST OF MAINLAND MEXICO. ADDITIONAL WATCHES AND WARNINGS MAY BE REQUIRED OVERNIGHT OR ON TUESDAY. 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 AS SOON AS POSSIBLE. REMEMBER NOT TO FOCUS ON THE EXACT FORECAST TRACK...SINCE DANGEROUS IMPACTS WILL EXTEND SOME DISTANCE FROM THE CENTER REGARDLESS OF THE LANDFALL LOCATION. FORECAST POSITIONS AND MAX WINDS INITIAL 01/0300Z 19.4N 109.6W 135 KT 12HR VT 01/1200Z 20.7N 110.4W 135 KT 24HR VT 02/0000Z 22.5N 111.2W 125 KT 36HR VT 02/1200Z 24.5N 111.9W 110 KT 48HR VT 03/0000Z 26.1N 112.4W 75 KT 72HR VT 04/0000Z 28.2N 112.8W 50 KT...INLAND 96HR VT 05/0000Z 30.0N 113.0W 50 KT...OVER WATER 120HR VT 06/0000Z 31.5N 112.5W 30 KT...INLAND $$ FORECASTER BRENNAN