000 WTPZ43 KNHC 020900 TCDEP3 HURRICANE JIMENA DISCUSSION NUMBER 19 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP132009 200 AM PDT WED SEP 02 2009 THE SATELLITE PRESENTATION OF JIMENA APPEARED TO BE DETERIORATING SIGNIFICANTLY SEVERAL HOURS AGO...BUT RECENTLY A NEW CONVECTIVE BAND HAS DEVELOPED THAT WRAPS AROUND THE WESTERN SIDE OF THE CIRCULATION. RECENT TRMM PASSES AT 2340 UTC AND 0612 UTC SUGGEST THAT A MID-LEVEL CENTER OF CIRCULATION WAS SHED OFF TOWARD THE NORTHEAST BUT THAT THE LOW-LEVEL CLOUD PATTERN REMAINS LARGELY SYMMETRIC. DVORAK T-NUMBERS HAVE CONTINUED TO DECREASE...AND AN AVERAGE OF THE SUBJECTIVE AND OBJECTIVE TECHNIQUES YIELDS AN INITIAL INTENSITY OF 90 KT. THE 0612 UTC TRMM OVERPASS INDICATED THAT THE LOW-LEVEL CENTER HAS MOVED A LITTLE TO THE WEST OF THE PREVIOUS FORECAST TRACK...AND THE INITIAL MOTION IS ESTIMATED AT 340/11. THE MODEL GUIDANCE IS IN GOOD AGREEMENT FOR THE NEXT 24 HOURS AND SHOWS THE CENTER OF JIMENA MOVING NORTH-NORTHWESTWARD VERY NEAR CABO SAN LAZARO. ONLY THE UKMET IS AN OUTLIER BY SHOWING A MORE SUDDEN NORTHWARD TURN INLAND. BEYOND 24 HOURS OR SO...THE NORTHWARD MOTION OF JIMENA IS EXPECTED TO BE IMPEDED BY A MID-LEVEL ANTICYCLONE LOCATED OVER THE SOUTHWESTERN UNITED STATES. CONSEQUENTLY...THE MODEL ENVELOPE SHOWS JIMENA SLOWING DOWN CONSIDERABLY BY 36-48 HOURS FOLLOWED BY A SLOW WESTWARD DRIFT AT DAYS 3 AND 4. THE NEW OFFICIAL FORECAST IS SLOWED DOWN AND SHIFTED SOUTHWEST FROM THE PREVIOUS TRACK AND NOW INDICATES A SLOW WESTWARD TURN BEYOND 48 HOURS. SEA SURFACE TEMPERATURES CONTINUE TO DECREASE AS JIMENA MOVES NORTH-NORTHWESTWARD PARALLEL TO THE BAJA COAST...AND THE THERMOCLINE ALONG THAT PART OF THE COAST IS VERY SHALLOW DUE TO NORMAL COASTAL UPWELLING. COMBINED WITH POSSIBLE LAND INTERACTION...THIS IS EXPECTED TO CAUSE JIMENA TO CONTINUE TO WEAKEN OVER THE NEXT 24 HOURS. HOWEVER...THE OFFICIAL FORECAST STILL SHOWS JIMENA MOVING INLAND AS A HURRICANE. ONCE INLAND...WESTERLY UPPER-LEVEL WINDS ARE EXPECTED TO STRENGTHEN CONSIDERABLY...AND JIMENA SHOULD SPIN DOWN TO A TROPICAL DEPRESSION BY 48 HOURS AND A REMNANT LOW BY 72 HOURS. THE NEW FORECAST SHOWS DISSIPATION BY DAY 5 SINCE MOST OF THE GLOBAL MODEL FIELDS LOSE THE SURFACE CIRCULATION BY THEN. 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 02/0900Z 23.9N 111.9W 90 KT 12HR VT 02/1800Z 25.3N 112.5W 80 KT 24HR VT 03/0600Z 26.6N 113.0W 65 KT...ON THE BAJA COAST 36HR VT 03/1800Z 27.4N 113.5W 45 KT...INLAND 48HR VT 04/0600Z 27.7N 113.9W 30 KT...INLAND 72HR VT 05/0600Z 27.7N 114.5W 25 KT...REMNANT LOW INLAND 96HR VT 06/0600Z 27.5N 115.0W 20 KT...REMNANT LOW 120HR VT 07/0600Z...DISSIPATED $$ FORECASTER BERG/PASCH