Hurricane JOHN

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HURRICANE JOHN DISCUSSION NUMBER  19
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP112006
800 PM PDT FRI SEP 01 2006
 
SATELLITE IMAGERY AND MEXICAN RADAR DATA FROM LOS CABOS AND GUASAVE
INDICATE THAT THE 10-12 N MI WIDE EYE OF JOHN MADE LANDFALL NEAR 02Z
OVER CABO DEL ESTE IN SOUTHERN BAJA CALIFORNIA.  INFRARED IMAGERY
SHOWS THAT THE EYE IS GRADUALLY LOSING DEFINITION...BUT NOT YET
ENOUGH TO JUSTIFY DROPPING THE MAXIMUM WINDS.  THE INITIAL
INTENSITY REMAINS 95 KT BASED ON EARLIER AIRCRAFT DATA AND
SATELLITE INTENSITY ESTIMATES UNCHANGED FROM 6 HR AGO.  ONE
INTERESTING ASPECT OF THE INFRARED IMAGERY IS THAT JOHN HAS LOST
ITS CIRCULAR APPEARANCE WITH THE COLDER CLOUD TOPS EXTENDING TO THE
SOUTH-SOUTHWEST OF THE CENTER AS IF SHEAR IS OCCURRING.  SINCE NO
AVAILABLE DATA SHOWS SHEAR...THE REASON FOR THIS APPEARANCE IS
UNKNOWN.
 
THE INITIAL MOTION IS 335/8.  JOHN IS APPROACHING THE WESTERN END OF
A MID/UPPER-LEVEL RIDGE OVER NORTHERN MEXICO...WITH WATER VAPOR
IMAGERY SHOWING COMPLEX UPPER-LEVEL TROUGHING AND WESTERLY FLOW
OVER THE SOUTHWESTERN UNITED STATES.  THE LATEST RUNS OF THE
LARGE-SCALE MODELS ARE SHOWING LITTLE RIDGING BUILDING WESTWARD TO
THE NORTH OF JOHN...AND THUS ARE CALLING FOR THE STORM TO MOVE
GENERALLY NORTH-NORTHWESTWARD TOWARD THE NORTHERN GULF OF
CALIFORNIA AND POSSIBLY INTO THE SOUTHWESTERN UNITED STATES.  THE
NOGAPS AND THE GFS ENSEMBLE MEAN HAVE SIGNIFICANT JUMPS TO THE
RIGHT...AND ONLY THE CANADIAN AND THE ECMWF STILL TAKE JOHN
WESTWARD INTO THE PACIFIC WEST OF BAJA.  THE NEW FORECAST TRACK IS
SHIFTED NOTABLY TO THE EAST AND NORTH OF THE PREVIOUS TRACK...BUT
NOT AS FAR EAST AS THE MODEL GUIDANCE AFTER 72 HR.  SHOULD THE
CURRENT MODEL TRENDS CONTINUE...THE LATER PART OF THE FORECAST
TRACK WILL REQUIRE ADDITIONAL SHIFTS IN SUBSEQUENT ADVISORIES.
 
THE FORECAST TRACK TAKES THE CENTER OF JOHN CLOSE ENOUGH TO BAJA
CALIFORNIA FOR LAND INTERACTION TO AFFECT THE INTENSITY.  WITH AN
INCREASING AMOUNT OF INFLOW COMING OVER THE MOUNTAINOUS LAND...THE
CYCLONE SHOULD GRADUALLY WEAKEN DURING THE NEXT 24-36 HR.  THE
INTENSITY FORECAST AFTER THAT TIME IS DEPENDENT ON THE EXACT TRACK. 
SHOULD THE CYCLONE STAY OVER OR CLOSE TO THE GULF OF CALIFORNIA...
IT WILL PROBABLY WEAKEN SLOWER DURING THE POST-36 HR PERIOD THAN
SHOWN HERE.
 
IT IS TOO EARLY TO TELL WHETHER JOHN WILL REACH THE SOUTHWESTERN
UNITED STATES AS A TROPICAL CYCLONE.  HOWEVER...MOISTURE FROM THE
CYCLONE IS LIKELY TO MOVE OVER THAT REGION EVEN IF THE LOW-LEVEL
CENTER DOES NOT.

 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      02/0300Z 23.4N 109.6W    95 KT
 12HR VT     02/1200Z 24.4N 110.1W    85 KT
 24HR VT     03/0000Z 25.5N 110.9W    75 KT
 36HR VT     03/1200Z 26.7N 111.8W    55 KT...INLAND
 48HR VT     04/0000Z 27.5N 113.0W    35 KT...INLAND
 72HR VT     05/0000Z 29.0N 115.0W    30 KT...OVER WATER
 96HR VT     06/0000Z 30.0N 117.5W    25 KT...DISSIPATING
120HR VT     07/0000Z 30.5N 119.0W    20 KT...REMNANT LOW
 
$$
FORECASTER BEVEN
 
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