Hurricane JIMENA

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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
 
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