Hurricane COSME

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HURRICANE COSME DISCUSSION NUMBER  11
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP062007
800 PM PDT MON JUL 16 2007

SATELLITE IMAGERY THIS EVENING INDICATES THAT THE EYE SEEN EARLIER
HAS DISAPPEARED...WITH COSME NOW SHOWING A SLIGHTLY RAGGED CENTRAL
DENSE OVERCAST WITH TOPS COLDER THAN -70C.  SATELLITE INTENSITY
ESTIMATES REMAIN 65 KT FROM TAFB AND SAB...AND THAT REMAINS THE
INITIAL INTENSITY FOR THIS ADVISORY.  MICROWAVES IMAGES DUE DURING
THE NEXT SEVERAL HOURS SHOULD PROVIDE ADDITIONAL INFORMATION ON THE
CONVECTIVE STRUCTURE UNDER THE CDO.  IT SHOULD BE NOTED THAT WHILE
THE CONVECTIVE MASS AND STRONG WIND FIELDS ASSOCIATED WITH COSME
COVER A FAIRLY SMALL AREA...IT HAS A RATHER LARGE OVERALL CYCLONIC
ENVELOPE ON THE ORDER OF 400 N MI ACROSS.
 
THE INITIAL MOTION IS NOW 295/11.  THERE IS LITTLE CHANGE TO THE
FORECAST TRACK PHILOSOPHY FROM THE PREVIOUS PACKAGE.  A LOW/
MID-LEVEL RIDGE NORTH AND NORTHWEST OF COSME SHOULD STEER THE
CYCLONE WEST-NORTHWESTWARD TO WESTWARD WITH SOME INCREASE IN
FORWARD SPEED DURING THE FORECAST PERIOD.  THE TRACK GUIDANCE IS IN
GOOD AGREEMENT WITH THIS SCENARIO...WITH THE GUIDANCE SPREAD
BETWEEN THE MORE NORTHERLY NOGPAS THAT TRACKS A WEAKENING COSME
THROUGH THE HAWAIIAN ISLANDS...AND THE SOUTHERLY GFS AND ECMWF THAT
TRACK IT ABOUT 100-150 N MI SOUTH OF THE BIG ISLAND.  THE FORECAST
TRACK IS SHIFTED A LITTLE TO THE RIGHT OF THE PREVIOUS FORECAST FOR
THE FIRST 72 HR BASED MAINLY ON THE INITIAL POSITION AND MOTION...
AND IS SIMILAR TO THE PREVIOUS TRACK THEREAFTER.  THE NEW TRACK IS
DOWN THE MIDDLE OF THE GUIDANCE ENVELOPE IN GOOD AGREEMENT WITH THE
CONSENSUS MODELS.

THE HURRICANE IS CURRENTLY IN AN ENVIRONMENT OF LIGHT/MODERATE
EASTERLY VERTICAL SHEAR.  COSME WILL BE SPENDING THE NEXT 72 HR
OVER GRADUALLY DECREASING SEA SURFACE TEMPERATURES.  THUS...THE
STORM SHOULD WEAKEN EVEN THOUGH THE UPPER-LEVEL WINDS ARE FORECAST
TO REMAIN FAVORABLE.  AFTER 72 HR...THE SSTS INCREASE ALONG THE
FORECAST TRACK...BUT THE LARGE-SCALE MODELS FORECAST MODERATE
WESTERLY SHEAR TO DEVELOP.  GIVEN THESE MIXED SIGNALS... THE
INTENSITY FORECAST WILL CONTINUE TO CALL FOR SLOW WEAKENING AS PER
THE PREVIOUS FORECASTS.  HOWEVER... COSME COULD BE STRONGER THAN
FORECAST AFTER 72 HR IF IT GOES SOUTH OF THE CURRENT FORECAST TRACK
THROUGH AN AREA OF FORECAST LIGHTER SHEAR.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      17/0300Z 15.1N 132.6W    65 KT
 12HR VT     17/1200Z 15.5N 134.2W    65 KT
 24HR VT     18/0000Z 15.9N 136.4W    60 KT
 36HR VT     18/1200Z 16.3N 138.8W    55 KT
 48HR VT     19/0000Z 16.7N 141.4W    50 KT
 72HR VT     20/0000Z 18.0N 147.0W    45 KT
 96HR VT     21/0000Z 18.5N 153.5W    40 KT
120HR VT     22/0000Z 19.0N 159.0W    35 KT
 
$$
FORECASTER BEVEN
 
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