Hurricane PAUL

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HURRICANE PAUL DISCUSSION NUMBER  12
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP172006
800 PM PDT MON OCT 23 2006
 
TWO AMSU OVERPASSES...AN AMSR-E OVERPASS...AND A WINDSAT OVERPASS
DURING THE PAST 6 HR INDICATE THAT PAUL IS LOSING ORGANIZATION...
WITH THE LOW LEVEL CENTER PARTLY EXPOSED TO THE SOUTH OF THE MAIN
CONVECTION.  THIS IS LIKELY DUE TO THE ONSET OF SOUTHWESTERLY
SHEAR...ALTHOUGH THIS SHEAR MAY BE OCCURRING BELOW THE RATHER
IMPRESSIVE OUTFLOW CIRRUS IN THE NORTHWESTERN SEMICIRCLE.  THE
INITIAL INTENSITY IS REDUCED TO 75 KT BASED ON THE EARLIER AIRCRAFT
DATA AND THE OBSERVED DECREASE IN ORGANIZATION SINCE THAT TIME.

THE MODELS HAVE COME INTO BETTER AGREEMENT THAT PAUL SHOULD WEAKEN
DURING THE NEXT 48 HR DUE TO INCREASING SOUTHWESTERLY SHEAR.  THE
GFDL...WHICH PREVIOUSLY CALLED FOR STRENGTHENING UNTIL LANDFALL...
NOW CALLS FOR PAUL TO GRADUALLY WEAKEN AND MAKE LANDFALL AS A
TROPICAL STORM...AS DOES THE SHIPS MODEL.  THE INTENSITY FORECAST
WILL CALL FOR A LITTLE LESS WEAKENING...WITH PAUL FORECAST TO MAKE
LANDFALL AS A 65-KT HURRICANE.  AN ALTERNATIVE SCENARIO IS
SUGGESTED BY THE GLOBAL MODELS...ALL OF WHICH SHOWING THE
MID/UPPER-LEVEL CENTER OF PAUL PARTING COMPANY WITH THE LOW-LEVEL
CENTER...WHICH COULD CAUSE PAUL TO WEAKEN MUCH FASTER THAN
CURRENTLY FORECAST.  THIS IS PARTICULARLY NOTEWORTHY IN THE
UKMET...WHICH HAS THE 500 MB CENTER WELL EAST OF THE SURFACE CENTER
BY 12Z TUESDAY.  

THE MICROWAVE DATA SHOWS THAT THE INITIAL MOTION IS 355/6.   THE
TRACK FORECAST IS VERY MUCH DEPENDENT ON HOW WELL PAUL HOLDS
TOGETHER.  THE NEW TRACK FORECAST IS BASED ON THE PREMISE THAT PAUL
WILL RETAIN SOME VERTICAL INTEGRITY...AND THUS CALLS FOR GRADUAL
ACCELERATION TOWARD THE NORTH-NORTHEAST BETWEEN A MID/UPPER-LEVEL
RIDGE OVER MEXICO AND A LARGE MID/UPPER-LEVEL TROUGH COVERING MUCH
OF THE NORTHEASTERN PACIFIC SOUTH OF 35N.  THE NEW FORECAST TRACK
IS SHIFTED A LITTLE TO THE LEFT OF THE PREVIOUS TRACK AND IS
SOMEWHAT SLOWER BASED ON THE CURRENT POSITION AND MOTION.  IF PAUL
SHEARS APART AS FORECAST BY THE GLOBAL MODELS...THERE IS A
POSSIBILITY THAT THE REMNANT LOW-LEVEL CIRCULATION MAY MEANDER OVER
WATER AND NEVER MAKE LANDFALL.  THE MOST EXTREME EXAMPLE OF THIS IN
THE GLOBAL MODELS IS THE UKMET...WHICH NEVER BRINGS THE LOW-LEVEL
CENTER NORTH OF 20N.  
 
BOTH THE TRACK AND INTENSITY FORECAST ARE RATHER LOW CONFIDENCE...
AND THUS INTERESTS IN SOUTHERN BAJA CALIFORNIA AND NORTHWESTERN
MAINLAND MEXICO SHOULD CONTINUE TO MONITOR THE PROGRESS OF PAUL.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      24/0300Z 17.6N 111.7W    75 KT
 12HR VT     24/1200Z 18.7N 111.6W    75 KT
 24HR VT     25/0000Z 20.5N 110.6W    70 KT
 36HR VT     25/1200Z 22.7N 109.1W    65 KT
 48HR VT     26/0000Z 25.0N 106.0W    30 KT...INLAND
 72HR VT     27/0000Z...DISSIPATED
 
$$
FORECASTER BEVEN
 
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