Hurricane JIMENA
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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
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