000
WTPZ42 KNHC 201439
TCDEP2
 
TROPICAL STORM GREG DISCUSSION NUMBER  16
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP072011
800 AM PDT SAT AUG 20 2011

BURSTS OF DEEP CONVECTION CONTINUE TO FLARE CLOSE TO THE CENTER OF
A WEAKENING GREG. SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB
ARE 45 AND 35 KT...RESPECTIVELY...WHILE THE FINAL T NUMBERS CAME IN
AT 35 AND 30 KT. THE INITIAL INTENSITY HAS BEEN LOWERED TO 35
KT...ESSENTIALLY AN AVERAGE OF THE DVORAK GUIDANCE.

THE INITIAL MOTION IS 275/09...AND LITTLE CHANGE HAS BEEN MADE TO
THE PREVIOUS FORECAST TRACK. GREG WILL CONTINUE TO BE STEERED ON A
SLIGHTLY NORTH OF DUE WEST TRACK TODAY BY THE NORTHEAST PACIFIC
SUBTROPICAL HIGH. THE HIGH WILL BE WEAKENING SLIGHTLY OVER THE NEXT
COUPLE OF DAYS AS A MID TO UPPER LEVEL TROUGH DIGS OFF THE WEST
COAST. THIS IS EXPECTED TO HAVE LITTLE IMPACT ON GREG...WHICH WILL
BECOME INCREASINGLY SHALLOW AND SHOULD BE STEERED TO THE WEST
SOUTHWEST BY THE HIGH. THE FORECAST TRACK IS ESSENTIALLY DOWN THE
MIDDLE OF THE GUIDANCE ENVELOPE.

GREG IS WEAKENING OVER COOL WATERS AND IS INGESTING STABLE AIR FROM
THE NORTH. AN ASCAT PASS FROM LAST EVENING DETECTED WINDS OF 30 TO
35 MAINLY WITHIN THE NORTH SEMICIRCLE...AND THESE DATA HAVE BEEN
INCORPORATED INTO THE WIND RADII AND INTENSITY. SSTS ARE BARELY
OVER 23C AND WILL CHANGE LITTLE OVER THE NEXT COUPLE OF DAYS. AS A
RESULT...GREG SHOULD CONTINUE TO STEADILY WEAKEN AND GRADUALLY SPIN
DOWN INTO A REMNANT LOW PRESSURE SYSTEM BY 24 HOURS OR SO.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  20/1500Z 19.7N 120.0W   35 KT  40 MPH
 12H  21/0000Z 19.8N 121.4W   30 KT  35 MPH
 24H  21/1200Z 19.7N 123.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 36H  22/0000Z 19.4N 124.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  22/1200Z 19.0N 125.8W   20 KT  25 MPH...POST-TROP/REMNT LOW
 72H  23/1200Z 18.0N 128.1W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  24/1200Z...DISSIPATED
 
$$
FORECASTER AVILA/WROE