Tropical Storm JOHN

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TROPICAL STORM JOHN DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP112006
200 PM PDT MON AUG 28 2006
 
BANDING FEATURES CONTINUE TO IMPROVE ON THIS TROPICAL CYCLONE WITH
TAFB PROVIDING A DVORAK ESTIMATE OF 2.5 OR 35 KT AND SAB GIVING 3.0
OR 45 KT.  INITIAL INTENSITY IS A BLEND OF THE TWO AT 40 KT AND THE
CYCLONE IS UPGRADED TO A TROPICAL STORM.  TROPICAL STORM FORCE WIND
RADII ARE UNCERTAIN...BUT ESTIMATED TO BE ABOUT 30 NMI IN THE RIGHT
SEMICIRCLE. 

SCATTER IN THE POSITION ESTIMATES HAS DECREASED AS ALL AGENCIES ARE
WITHIN 25 NMI OF EACH OTHER.  THE CURRENT POSITION WAS CORROBORATED
WITH A TRMM PASS AT 1456Z WITH WELL-PRONOUNCED CONVECTIVE BANDS. 
MOTION IS NOW MORE ACCURATELY ASSESSED AT 285/7...RATHER THAN THE
NORTHWEST TRACK INDICATED IN THE PREVIOUS ADVISORY.  JOHN SHOULD
MOVE TOWARD THE WEST-NORTHWEST FOR THE NEXT 24 HOURS...THEN TURN
TOWARD THE NORTHWEST THEREAFTER UNDER THE INFLUENCE OF A DEEP LAYER
RIDGE CENTERED OVER NORTHWEST MEXICO.  ON DAYS FOUR AND FIVE...A
MID TO UPPER LEVEL SHORTWAVE TROUGH DIGS SOUTHWARD OFF OF SOUTHERN
CALIFORNIA...BUT IT DOES NOT APPEAR AT THIS TIME TO HAVE A
SIGNIFICANT IMPACT ON JOHN'S MOTION.  THE TRACK FORECAST IS MOST
SIMILAR TO THE GFS AND GFDL GUIDANCE AS BOTH THE UKMET AND NOGAPS
DO NOT APPEAR TO HAVE ACCURATELY ANALYZED JOHN.
 
ALL ENVIRONMENTAL FACTORS OVER THE NEXT FEW DAYS SUGGEST CONTINUED
INTENSIFICATION.  BECAUSE OF THESE FACTORS...THE SHIPS...GFDL AND
FSU SUPER-ENSEMBLE INTENSITY MODELS ALL BRING THE SYSTEM UP TO A
CATEGORY TWO HURRICANE WITHIN THREE DAYS.  WHILE THE INTENSITY
FORECAST SHOWN HERE SUGGESTS JOHN WILL BECOME A HURRICANE BY 36
HOURS...THE NORTHEAST PACIFIC RAPID INTENSIFICATION INDEX INDICATES
THAT JOHN MAY REACH HURRICANE INTENSITY SOONER THAN INDICATED.  THE
SYSTEM IS LIKELY TO BEGIN WEAKENING BY DAY FIVE DUE TO COOLER SSTS
AND A MORE STABLE ATMOSPHERE.  THE INTENSITY FORECAST IS MOST
SIMILAR TO THE SHIPS AND FSU SUPER-ENSEMBLE MODELS...EXCEPT TO SHOW
FASTER WEAKENING AT DAY FIVE.

GIVEN THE CLOSE PROXIMITY OF JOHN'S TRACK TO THE COAST OF
MEXICO...INTERESTS FROM ACAPULCO TO LA FORTUNA SHOULD CLOSELY
MONITOR THE PROGRESS OF THIS SYSTEM.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      28/2100Z 13.4N  96.7W    40 KT
 12HR VT     29/0600Z 13.7N  97.9W    50 KT
 24HR VT     29/1800Z 14.1N  99.7W    60 KT
 36HR VT     30/0600Z 15.0N 101.6W    70 KT
 48HR VT     30/1800Z 16.2N 103.7W    80 KT
 72HR VT     31/1800Z 19.5N 108.5W    90 KT
 96HR VT     01/1800Z 21.5N 112.0W    85 KT
120HR VT     02/1800Z 22.5N 114.0W    60 KT
 
$$
FORECASTER PASCH/LANDSEA
 
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