Hurricane HILARY
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HURRICANE HILARY DISCUSSION NUMBER 24
NWS NATIONAL HURRICANE CENTER MIAMI FL EP092011
800 PM PDT MON SEP 26 2011
THE CLOUD PATTERN ASSOCIATED WITH HILARY HAS DEGRADED SINCE THIS
AFTERNOON WITH THE EYE FILLING AND THE CONVECTIVE CLOUD TOPS
WARMING. AS A RESULT...SUBJECTIVE DVORAK AND UW-CIMSS ADT
T-NUMBERS HAVE DECREASED A LITTLE...AND A BLEND OF THESE NUMBERS
YIELDS AN INITIAL INTENSITY OF 110 KT. HILARY HAS STARTED ITS
PROGRESSION OVER SLIGHTLY COOLER SSTS...AND GRADUAL WEAKENING IS
PREDICTED OVER THE NEXT DAY OR SO. IN 2 TO 3 DAYS...THE HURRICANE
SHOULD CROSS THE 26C ISOTHERM AND OVER MUCH COLDER WATER DURING THE
REMAINDER OF THE PERIOD. THIS...COMBINED WITH INCREASING
SOUTHWESTERLY SHEAR...SHOULD CAUSE HILARY TO RAPIDLY WEAKEN. THE
NHC INTENSITY FORECAST IS CLOSE TO THE INTENSITY CONSENSUS DURING
THE FIRST 36 HOURS...AND THEREAFTER IT IS IN GOOD AGREEMENT WITH
THE LGEM MODEL.
HILARY HAS BEEN MOVING NEARLY DUE WESTWARD DURING THE PAST SEVERAL
HOURS AT A SLIGHTLY SLOWER FORWARD SPEED OF 8 KT. WATER VAPOR
IMAGERY SHOWS THAT THE MID- TO UPPER-LEVEL LOW NEAR 28N131W IS
BEGINNING TO SLIDE EASTWARD. AS THIS OCCURS...THE RIDGE THAT
HAS BEEN STEERING HILARY WESTWARD FOR THE PAST SEVERAL DAYS
SHOULD WEAKEN. THE HURRICANE IS THEN FORECAST TO TURN SHARPLY
NORTHWARD AROUND THE EASTERN PERIPHERY OF THE MID/UPPER-LOW AS
IT MOVES SOUTHEASTWARD. THE LATEST RUN OF THE GFS MODEL REMAINS
ALONG THE FAR EASTERN EDGE OF THE MODEL ENVELOPE...TURNING HILARY
NORTHWARD MUCH SOONER THAN THE REMAINDER OF THE GUIDANCE. THE
EARLIER NORTHWARD AND NORTHEASTWARD MOTION SHOWN BY THIS MODEL
KEEPS HILARY OVER WARMER WATER AND IN LESS SHEAR...AND CONSEQUENTLY
MAINTAINS THE CYCLONE AS A DEEP SYSTEM THAT MOVES QUICKLY
NORTHEASTWARD ACROSS THE BAJA PENINSULA. THE REMAINDER OF THE
GUIDANCE SHOWS THE HURRICANE MOVING MORE WESTWARD DURING THE NEXT
DAY OR SO...WHICH RESULTS IN THE CYCLONE REACHING COOLER WATER
SOONER. THE LATTER MODELS THEN WEAKEN HILARY AND DEPICT A SHALLOW
SYSTEM THAT SLOWS DOWN AND EVENTUALLY TURNS NORTHWESTWARD IN THE
LOW- TO MID-LEVEL FLOW. THE NHC FORECAST PUTS LESS WEIGHT ON THE
GFS SOLUTION...BUT IS NOT NEARLY AS FAR LEFT AS THE ECMWF AND UKMET
MODELS. THE NEW TRACK HAS BEEN ADJUSTED A LITTLE WEST OF THE
PREVIOUS ADVISORY AND IS CLOSE TO A CONSENSUS OF THE GFDL...HWRF...
NOGAPS...AND ECMWF MODELS.
FORECAST POSITIONS AND MAX WINDS
INIT 27/0300Z 16.6N 114.8W 110 KT 125 MPH
12H 27/1200Z 16.8N 115.8W 105 KT 120 MPH
24H 28/0000Z 17.2N 116.6W 95 KT 110 MPH
36H 28/1200Z 17.9N 116.9W 90 KT 105 MPH
48H 29/0000Z 19.1N 116.9W 80 KT 90 MPH
72H 30/0000Z 21.7N 116.9W 60 KT 70 MPH
96H 01/0000Z 24.0N 117.0W 35 KT 40 MPH
120H 02/0000Z 26.5N 117.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
$$
FORECASTER BROWN
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