Tropical Storm EARL

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TROPICAL STORM EARL DISCUSSION NUMBER  12
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL072010
500 AM AST SAT AUG 28 2010
 
EARL HAS BECOME BETTER ORGANIZED THIS MORNING. THE CLOUD PATTERN
CONSISTS OF A CENTRAL DENSE OVERCAST WITH CLOUD TOPS TO -80 C AND A
LARGE CURVED BAND OVER THE WESTERN SEMICIRCLE OF THE STORM. THE
CIRRUS OUTFLOW HAS IMPROVED TO THE SOUTH AND WEST OF THE CENTER BUT
REMAINS RESTRICTED OVER THE EASTERN SEMICIRCLE. DVORAK
CLASSIFICATIONS ARE 45 KT AND 55 KT FROM TAFB AND SAB...
RESPECTIVELY.  ON THIS BASIS...THE INITIAL INTENSITY IS INCREASED TO
50 KT FOR THIS ADVISORY.
 
A 0413 UTC TRMM OVERPASS INDICATED THAT THE LOW-LEVEL CENTER OF EARL
WAS LOCATED A LITTLE TO THE SOUTH OF THE PREVIOUS ESTIMATES.  USING
A COMBINATION OF THIS OVERPASS AND SATELLITE FIXES YIELDS AN
INITIAL MOTION OF 270/18.  A MID-LEVEL RIDGE LOCATED OVER THE
SUBTROPICAL CENTRAL ATLANTIC IS EXPECTED TO KEEP EARL ON A RATHER
QUICK WESTWARD TO WEST-NORTHWESTWARD COURSE FOR THE NEXT DAY OR
TWO.  THEREAFTER...THE CYCLONE IS EXPECTED TO NEAR A BREAK IN THE
RIDGE...AND THAT SHOULD CAUSE A TURN TO THE NORTHWEST. WHILE THE
GLOBAL MODELS AGREE ON THE GENERAL EVOLUTION OF THE LARGE SCALE
PATTERN...THERE ARE CONSIDERABLE DIFFERENCES ON THE DETAILS OF THE
TIMING...LOCATION AND SHARPNESS OF THE TURN.  THE OFFICIAL FORECAST
IS NUDGED A LITTLE TO THE LEFT OF THE PREVIOUS ONE TO ACCOUNT FOR
THE INITIAL POSITION AND MOTION AND TRENDS TOWARD THE MULTI-MODEL
CONSENSUS. 
 
ALL OF THE INTENSITY GUIDANCE SHOWS ADDITIONAL INTENSIFICATION
DURING THE NEXT FEW DAYS...AS EARL MOVES OVER EVEN WARMER WATERS AND
INTO A MORE FAVORABLE UPPER-LEVEL WIND ENVIRONMENT. THE OFFICIAL
FORECAST IS ADJUSTED UPWARD FOR THE FIRST COUPLE OF DAYS AND NOW
BRINGS EARL TO HURRICANE STRENGTH IN 24 HOURS AND TO MAJOR
HURRICANE STATUS IN 3 DAYS.  BEYOND 72 HOURS...SOUTHWESTERLY SHEAR
IS EXPECTED TO INCREASE...WHICH SHOULD HALT INTENSIFICATION AND
POSSIBLY INDUCE GRADUAL WEAKENING.  THIS IS REFLECTED IN THE 
OFFICIAL FORECAST...WHICH IS IN BEST AGREEMENT WITH THE INTENSITY
MODEL CONSENSUS.

THE FORECAST NECESSITATES THE ISSUANCE OF TROPICAL STORM WATCHES FOR
PORTIONS OF THE NORTHERN LEEWARD ISLANDS. 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      28/0900Z 15.7N  50.1W    50 KT
 12HR VT     28/1800Z 16.0N  52.7W    60 KT
 24HR VT     29/0600Z 16.5N  55.7W    65 KT
 36HR VT     29/1800Z 17.2N  58.3W    75 KT
 48HR VT     30/0600Z 18.2N  60.5W    85 KT
 72HR VT     31/0600Z 20.8N  64.2W   100 KT
 96HR VT     01/0600Z 24.5N  67.5W   110 KT
120HR VT     02/0600Z 29.5N  69.5W   100 KT
 
$$
FORECASTER CANGIALOSI/BRENNAN
 
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