Tropical Storm JOHN

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TROPICAL STORM JOHN DISCUSSION NUMBER  24
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP112006
200 AM PDT SUN SEP 03 2006
 
THE INITIAL INTENSITY IS SET AT 45 KT BASED ON A RECENT QUIKSCAT
PASS NEAR 0200 UTC AND A REPORT OF 37 KT FROM SHIP D5XH JUST
NORTHEAST OF THE CENTER. 

JOHN CONTINUES TO MOVE TOWARD THE NORTHWEST OR 325/7.  THE TRACK
FORECAST REMAINS PROBLEMATIC DUE TO LAND INTERACTION AND LARGE
DISCREPANCIES IN THE STEERING FLOW BETWEEN THE VARIOUS NHC TRACK
MODELS.  THE SOLUTIONS RANGE FROM THE GFS AND NOGAPS MODELS WHICH
FORECAST JOHN TO GRADUALLY TURN NORTHEAST OVER MAINLAND MEXICO TO
THE CANADIAN AND GFS ENSEMBLE MEAN WHICH SHOW JOHN TURNING TOWARD
THE WEST ALMOST IMMEDIATELY. INTERESTINGLY...THE GFS DIFFERS BY
ALMOST 180 DEGREES FROM ITS ENSEMBLE MEAN.  THE UKMET AND EUROPEAN
MODELS APPEAR TO PROVIDE THE MOST REALISTIC SOLUTIONS BY SHOWING
THE LOWER LEVEL CIRCULATION TURNING WEST BEYOND 36 HOURS AS IT
BECOMES DECOUPLED FROM THE NORTHEASTWARD MOVING MIDDLE TO UPPER
LEVEL CIRCULATION. THE OFFICIAL FORECAST FOLLOWS SUIT BY ASSUMING
JOHN WILL CONTINUE TO MOVE NORTHWEST WITHIN A MID-LEVEL WEAKNESS
UNTIL THE CYCLONE BECOMES COMPLETELY DECOUPLED IN A DAY OR SO. 
THEREAFTER...THE REMNANT LOW-LEVEL CIRCULATION IS EXPECTED TO TURN
TOWARD THE WEST IN LINE WITH THE SHALLOW BAM MODEL. REGARDLESS OF
THE EXACT TRACK...A MIDDLE TO UPPER-LEVEL TROUGH IS EXPECTED TO
PULL MOISTURE ASSOCIATED WITH JOHN NORTHEASTWARD AND ENHANCE
RAINFALL OVER THE SOUTHWESTERN UNITED STATES.
 
WITH JOHN FORECAST TO REMAIN OVER LAND FOR ANOTHER 24-36
HOURS...CONTINUED WEAKENING IS EXPECTED AND THE CYCLONE COULD
DISSIPATE OVER THE BAJA PENINSULA. SHOULD JOHN RE-EMERGE BACK OVER
THE EASTERN PACIFIC...REGENERATION IS NOT FORECAST DUE TO COLD
WATERS. 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      03/0900Z 26.3N 112.1W    45 KT...INLAND
 12HR VT     03/1800Z 27.1N 112.7W    35 KT...INLAND
 24HR VT     04/0600Z 28.1N 113.7W    30 KT...INLAND
 36HR VT     04/1800Z 29.2N 114.7W    25 KT...DISSIPATING INLAND
 48HR VT     05/0600Z 29.9N 115.8W    20 KT...REMNANT LOW
 72HR VT     06/0600Z 30.0N 118.0W    20 KT...REMNANT LOW
 96HR VT     07/0600Z...DISSIPATED
 
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FORECASTER RHOME/STEWART
 
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