Tropical Storm GREG

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TROPICAL STORM GREG DISCUSSION NUMBER  15
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP072011
200 AM PDT SAT AUG 20 2011
 
AFTER A SMALL BURST OF MODERATE TO DEEP CONVECTION AROUND 00Z...
CONVECTION HAS DWINDLED SOMEWHAT BOTH IN VERTICAL DEPTH AND
AREAL COVERAGE SINCE THEN. A BRIEF EYE-LIKE FEATURE HAS ALSO BEEN
REVEALED AS THE CIRRUS CANOPY HAS THINNED. SATELLITE INTENSITY
ESTIMATES ARE 45 KT AND 35 KT FROM TAFB AND SAB...RESPECTIVELY...SO
THE INITIAL INTENSITY IS LOWERED TO 40 KT FOR THIS ADVISORY.

THE INITIAL MOTION IS 275/09. GREG REMAINS ON TRACK SO THERE IS NO
SIGNIFICANT CHANGE TO THE PREVIOUS TRACK FORECAST RATIONALE. A
GRADUAL TURN TOWARD THE WEST-SOUTHWEST IS FORECAST AS GREG
CONTINUES TO WEAKEN OVER PROGRESSIVELY COOLER WATER...BECOMING A
SHALLOW SYSTEM AND BEING STEERED BY THE LARGE LOW-LEVEL CENTRAL
PACIFIC HIGH PRESSURE RIDGE TO THE NORTH OF THE CYCLONE. THE GLOBAL
MODELS ARE IN EXCELLENT AGREEMENT ON THIS SCENARIO...AND THE
FORECAST TRACK IS JUST AN EXTENSION OF THE PREVIOUS ADVISORY TRACK.

GREG IS CURRENTLY OVER 23.5C SSTS...AND ONLY COOLER WATER AND DRY
STABLE AIR LIE AHEAD OF THE CYCLONE. AS A RESULT OF THESE
UNFAVORABLE THERMODYNAMIC CONDITIONS...GREG SHOULD CONTINUE TO
STEADILY WEAKEN AND GRADUALLY SPIN DOWN INTO A NON-CONVECTIVE
REMNANT LOW PRESSURE SYSTEM BY 24 HOURS OR SO...AND DISSIPATE BY 96
HOURS...IF NOT SOONER.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  20/0900Z 19.7N 119.0W   40 KT  45 MPH
 12H  20/1800Z 19.8N 120.4W   30 KT  35 MPH
 24H  21/0600Z 19.7N 122.2W   30 KT  35 MPH...POST-TROP/REMNT LOW
 36H  21/1800Z 19.6N 123.7W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  22/0600Z 19.2N 125.1W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  23/0600Z 18.2N 127.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  24/0600Z...DISSIPATED
 
$$
FORECASTER STEWART
 
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