000
WTPZ42 KNHC 210851
TCDEP2
 
TROPICAL DEPRESSION GREG DISCUSSION NUMBER  19
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP072011
200 AM PDT SUN AUG 21 2011
 
THE LAST FEW PIXELS OF -50C OR COLDER CLOUD TOPS WAS EVIDENT ON
INFRARED SATELLITE IMAGERY AT 0600 UTC.  SATELLITE CURRENT
INTENSITY ESTIMATES WERE STILL 2.0 FROM TAFB AND SAB AT THAT
TIME...SO THE INITIAL INTENSITY WILL BE HELD AT 30 KT.  GRADUAL
WEAKENING IS FORECAST AS GREG MOVES OVER RELATIVELY COOL 22C TO 23C
WATERS AND INTO A MORE STABLE ENVIRONMENT.  IF NO DEEP CONVECTION
REDEVELOPS...GREG WOULD BECOME A POST-TROPICAL REMNANT LOW LATER
THIS MORNING OR THIS AFTERNOON.

FOR A DECAYING SYSTEM...THERE IS SIGNIFICANT SPREAD IN THE MODEL
TRACK GUIDANCE.  SOME OF THE MODELS...PARTICULARLY THE GFS...
GFDL...UKMET...AND NOGAPS SHOW GREG TAKING A DIVE TOWARD THE
SOUTHWEST OVER THE COMING DAYS.  ON THE OTHER HAND...THE ECMWF AND
BAM MODELS INDICATE THAT THE REMNANT LOW WILL TURN NORTHWESTWARD. 
SINCE GREG IS BECOMING A SHALLOW LOW-LEVEL SYSTEM...I WAS INCLINED
TO FOLLOW THE LEAD OF THE ECMWF AND BAM SHALLOW MODELS AND MOVED
THE NHC TRACK FORECAST A LITTLE TO THE NORTH OF THE PREVIOUS
ONE...ALSO ENDING UP NORTH OF THE MODEL CONSENSUS TVCE. 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  21/0900Z 20.2N 121.9W   30 KT  35 MPH
 12H  21/1800Z 20.4N 123.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 24H  22/0600Z 20.4N 124.4W   25 KT  30 MPH...POST-TROP/REMNT LOW
 36H  22/1800Z 20.2N 125.8W   20 KT  25 MPH...POST-TROP/REMNT LOW
 48H  23/0600Z 19.9N 127.2W   20 KT  25 MPH...POST-TROP/REMNT LOW
 72H  24/0600Z...DISSIPATED
 
$$
FORECASTER BERG