Hurricane HILARY

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HURRICANE HILARY DISCUSSION NUMBER  26
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP092011
800 AM PDT TUE SEP 27 2011
 
AFTER DECREASING OVERNIGHT...DEEP CONVECTION HAS INCREASED AGAIN
NEAR THE CENTER OF HILARY...EVEN THOUGH AN EYE IS NO LONGER
APPARENT IN INFRARED IMAGERY OR THE FIRST VISIBLE IMAGES. THE
INITIAL INTENSITY IS HELD AT 100 KT BASED ON A BLEND OF 12Z DVORAK
CI- AND FINAL-T NUMBERS FROM TAFB AND SAB. AS HILARY MOVES OVER
COOLER WATERS IN THE NEXT DAY OR SO...SLOW WEAKENING IS EXPECTED...
FOLLOWED BY STEADY WEAKENING AFTER THE CYCLONE CROSSES THE 26C
ISOTHERM IN ABOUT 36 HOURS. OUTPUT FROM THE SHIPS MODEL SHOWS
VERTICAL SHEAR INCREASING RAPIDLY AROUND 48 HOURS AND CONTINUING
THROUGH THE REMAINDER OF THE PERIOD. THIS SHEAR...IN COMBINATION
WITH HILARY MOVING OVER MUCH COLDER WATERS BY DAY 3 AND BEYOND
SHOULD RESULT IN RAPID WEAKENING TO A REMNANT LOW BY 4 DAYS. THE
NHC INTENSITY LIES BETWEEN THE OLD ONE AND THE LGEM THROUGH 36
HOURS...AND IS CLOSE TO THE LGEM BEYOND THAT TIME. 

THE INITIAL MOTION ESTIMATE IS 270/09. HILARY SHOULD TURN TOWARD THE
WEST-NORTHWEST AND SLOW DOWN LATER TODAY AS THE RIDGE TO THE NORTH
CONTINUES TO WEAKEN. AFTER THAT TIME A SHARP TURN TOWARD THE NORTH
IS EXPECTED BY 36 HOURS AS HILARY BEGINS TO INTERACT WITH AN
AMPLIFYING MID-LEVEL LOW CURRENTLY LOCATED NEAR 28N 129W.
OVERALL...THE SPREAD OF THE TRACK GUIDANCE HAS DECREASED THIS
CYCLE...AS THE LATEST RUN OF THE GFS SHOWS HILARY BEING PULLED A
LITTLE FARTHER WESTWARD BY THE MID-LEVEL LOW LATE IN THE PERIOD AND
HAS SHIFTED ITS TRACK WESTWARD TOWARD THE REST OF THE GUIDANCE
SUITE. THE ONLY CHANGE TO THE NHC TRACK FORECAST IS A SMALL SHIFT
TO THE LEFT THROUGH 48 HOURS TO ACCOUNT FOR THE INITIAL POSITION
AND MOTION. THE NEW NHC TRACK IS A LITTLE TO THE EAST OF THE TVCE
CONSENSUS AND THE ECMWF THROUGH 96 HOURS...AND IS CLOSE TO THE GFS
ENSEMBLE MEAN AT DAY 5. 

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  27/1500Z 16.8N 116.4W  100 KT 115 MPH
 12H  28/0000Z 17.1N 117.2W   95 KT 110 MPH
 24H  28/1200Z 17.9N 117.6W   85 KT 100 MPH
 36H  29/0000Z 19.0N 117.7W   75 KT  85 MPH
 48H  29/1200Z 20.2N 117.7W   65 KT  75 MPH
 72H  30/1200Z 23.0N 118.0W   45 KT  50 MPH
 96H  01/1200Z 25.0N 118.5W   30 KT  35 MPH...POST-TROP/REMNT LOW
120H  02/1200Z 27.0N 118.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
 
$$
FORECASTER BRENNAN
 
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