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Tropical Storm JOHN

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TROPICAL STORM JOHN DISCUSSION NUMBER  26
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP112006
200 PM PDT SUN SEP 03 2006
 
SOUTHWESTERLY SHEAR... ALONG WITH THE HIGH TERRAIN IN CENTRAL BAJA
CALIFORNIA... IS DISRUPTING THE CIRCULATION OF THE CYCLONE.
EVIDENCE OF THIS IS DISPLAYED ON SATELLITE PICTURES WITH A
MIDDLE-LEVEL CENTER SEEN OVER THE GULF OF CALIFORNIA NORTHEAST OF
THE APPARENT LOW-LEVEL CENTER. HOWEVER... EVEN WITH VISIBLE
IMAGES... THE EXACT CENTER OF JOHN IS DIFFICULT TO LOCATE.  SURFACE
WINDS AT SANTA ROSALIA HAVE SHIFTED FROM EASTERLY TO SOUTHEASTERLY
IN THE PAST 3 HOURS.. SO THE CENTER IS LIKELY WEST OF THAT
LOCATION. CONVECTION HAS BECOME RATHER DISORGANIZED IN THE PAST FEW
HOURS... AND THE INITIAL INTENSITY IS DECREASED TO 35 KT. THESE
WINDS ARE LIKELY CONFINED TO A SMALL AREA MOSTLY IN ONSHORE FLOW.
FURTHER WEAKENING SHOULD CONTINUE AND JOHN COULD DISSIPATE
TOMORROW.
 
BEST ESTIMATE IS THAT JOHN HAS SLOWED A LITTLE.. NOW 325/6.  THIS
GENERAL TRACK SEEMS LIKELY AS LONG AS THE MIDDLE-LEVEL CENTER STAYS
SOMEWHAT COUPLED WITH THE LOW-LEVEL CENTER.  IN GENERAL THE TRACK
GUIDANCE IS FARTHER TO THE NORTHEAST THAN 6 HOURS AGO.  THE
GFDL/GFS KEEP SHIFTING WILDLY FROM A MORE WESTWARD TO NORTHWARD
TRACK WHILE THE MOST OTHER GUIDANCE SUGGESTS A NORTHWESTWARD TRACK.
THE OFFICIAL FORECAST IS SHIFTED A TOUCH TO THE RIGHT OF THE
PREVIOUS FORECAST... CLOSER TO THE MODEL CONSENSUS.  THERE PROBABLY
WON'T BE MUCH LEFT OF JOHN TOMORROW... AND THE MAIN THREAT WILL
CONTINUE TO BE VERY HEAVY RAIN THROUGHOUT CENTRAL BAJA CALIFORNIA
AND NORTHWESTERN MEXICO... WITH SIGNIFICANT AMOUNTS SPREADING INTO
THE SOUTHWESTERN UNITED STATES. 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      03/2100Z 27.6N 112.7W    35 KT...INLAND
 12HR VT     04/0600Z 28.4N 113.2W    30 KT...INLAND
 24HR VT     04/1800Z 29.4N 114.0W    25 KT...DISSIPATING
 36HR VT     05/0600Z 30.2N 114.8W    20 KT...REMNANT LOW
 48HR VT     05/1800Z...DISSIPATED
 
$$
FORECASTER BLAKE/FRANKLIN
 
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