000
WTPZ44 KNHC 241459
TCDEP4
 
HURRICANE HILARY DISCUSSION NUMBER  14
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP092011
800 AM PDT SAT SEP 24 2011
 
HURRICANE HILARY IS EXHIBITING A PINHOLE EYE THIS MORNING AS
EVIDENCED BY THE FIRST VISIBLE SATELLITE IMAGERY AS WELL AS AN
0815Z AQUA MICROWAVE PASS.  A CONSENSUS OF THE TAFB/SAB SUBJECTIVE
DVORAK CLASSIFICATIONS AND THE ADVANCED DVORAK TECHNIQUE FROM CIMSS
SUGGESTS THAT 120 KT REMAINS THE INTENSITY.
 
SOMEWHAT SURPRISINGLY...THE HURRICANE HAS BEEN JOGGING TOWARD THE
SOUTHWEST DURING THE LAST FEW HOURS.  THIS MAY BE DUE TO A
TROCHOIDAL OSCILLATION NOT UNCOMMONLY SEEN IN MAJOR HURRICANES.  A
LONGER-TERM MOTION IS ANALYZED TO BE 270/10.  A MOTION TOWARD THE
WEST OR WEST-NORTHWEST AT A SLIGHTLY SLOWER FORWARD SPEED IS
EXPECTED DURING THE NEXT THREE DAYS AS HILARY IS STEERED ALONG THE
SOUTH SIDE OF A DEEP-LAYERED RIDGE.  BY DAYS 4 AND 5...A WEAKNESS
DEVELOPS IN THE RIDGE DUE TO A MID- TO UPPER-LEVEL LOW MOVING IN
FROM THE NORTHWEST...WHICH IS CURRENTLY SEEN IN THE WATER VAPOR
IMAGERY NEAR 23N140W.  HILARY SHOULD RESPOND BY TURNING SLOWLY
NORTHWARD NEAR 115W ON THOSE DAYS.  ALL OF THE RELIABLE TRACK
MODELS ARE IN MUCH BETTER AGREEMENT WITH THIS SCENARIO TODAY
COMPARED TO YESTERDAY...AS NONE OF THE GUIDANCE ARE TAKING HILARY
TO MEXICO WITHIN FIVE DAYS.  THE TRACK FORECAST IS SOMEWHAT SOUTH
OF THE PREVIOUS ADVISORY BECAUSE OF THE SHORT-TERM MOTION CHANGE
AND THEN JUST TO THE WEST OF THE PREVIOUS ADVISORY BY DAYS 4 AND
5...IN AGREEMENT WITH THE MULTI-MODEL CONSENSUS.
 
THE HURRICANE IS CURRENTLY IN A QUITE CONDUCIVE ENVIRONMENT OF LOW
VERTICAL SHEAR...WARM WATERS...AND ABUNDANT MOISTURE.  THE CYCLONE
IS EXPECTED TO REMAIN A MAJOR HURRICANE FOR THE NEXT TWO DAYS.
AFTER WHICH...A DRIER AND MORE STABLE ATMOSPHERE MAY BEGIN SOME
SIGNIFICANT WEAKENING OF HILARY.  BY THE END OF THE FORECAST
PERIOD...STRONG VERTICAL SHEAR AND COOL SSTS SHOULD CAUSE AN EVEN
QUICKER DECAY.  THE INTENSITY PREDICTION IS BASED UPON THE
SHIPS/LGEM/GFDL MODEL CONSENSUS AND IS VERY SIMILAR TO THE PREVIOUS
ADVISORY.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/1500Z 16.6N 106.2W  120 KT 140 MPH
 12H  25/0000Z 17.1N 107.6W  115 KT 135 MPH
 24H  25/1200Z 17.3N 109.3W  110 KT 125 MPH
 36H  26/0000Z 17.5N 110.9W  110 KT 125 MPH
 48H  26/1200Z 17.6N 112.4W  105 KT 120 MPH
 72H  27/1200Z 18.0N 115.0W   95 KT 110 MPH
 96H  28/1200Z 19.0N 116.0W   80 KT  90 MPH
120H  29/1200Z 21.5N 116.0W   65 KT  75 MPH
 
$$
FORECASTER LANDSEA/STEWART