000
WTPZ42 KNHC 190257
TCDEP2
 
HURRICANE GREG DISCUSSION NUMBER  10
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP072011
800 PM PDT THU AUG 18 2011
 
IT APPEARS THAT GREG HAS STARTED TO WEAKEN.  THE MOST RECENT
MICROWAVE IMAGERY INDICATES THAT THE EYE OF GREG HAS DISAPPEARED. 
GEOSTATIONARY IMAGERY SHOWED THAT THE CONVECTION NEAR THE CENTER
THINNED OUT LATE THIS AFTERNOON...BUT SINCE THAT TIME A NEW BURST
OF DEEP CONVECTION HAS FORMED OVER THE ESTIMATED CENTER.  DVORAK
T-NUMBERS HAVE STARTED TO DECREASE AND THE INITIAL INTENSITY IS
LOWERED TO 70 KT.  THE HURRICANE WILL BE MOVING OVER PROGRESSIVELY
COOLER WATER AND INTO A MORE STABLE ENVIRONMENT DURING THE NEXT FEW
DAYS.  THIS SHOULD CAUSE STEADY WEAKENING AND GREG IS FORECAST TO
BECOME A REMNANT LOW IN 3-4 DAYS.  
 
GREG IS MOVING WEST-NORTHWESTWARD OR 285 DEGREES AT 12 KT.  THERE
HAS BEEN NO CHANGE TO THE TRACK FORECAST REASONING.  GREG SHOULD
TURN WESTWARD TO THE SOUTH OF A MID/UPPER-LEVEL RIDGE THAT EXTENDS
FROM NORTHERN MEXICO INTO THE EASTERN PACIFIC.  THE WESTERN PORTION
OF THE RIDGE IS FORECAST TO WEAKENING DURING THE NEXT DAY OR SO.  
THIS SHOULD RESULT IN A SLOW DOWN OF THE FORWARD SPEED OF THE
CYCLONE.  AS GREG WEAKENS AND BECOMES A SHALLOW CYCLONE...IT IS
LIKELY TO TURN TOWARD THE WEST-SOUTHWEST IN THE LOW-LEVEL
NORTHEASTERLY FLOW.  THE NEW TRACK FORECAST IS ESSENTIALLY AN
UPDATE OF THE PREVIOUS ADVISORY AND IS NEAR THE MULTI-MODEL
CONSENSUS.
  
FORECAST POSITIONS AND MAX WINDS
 
INIT  19/0300Z 18.9N 113.9W   70 KT  80 MPH
 12H  19/1200Z 19.1N 115.7W   65 KT  75 MPH
 24H  20/0000Z 19.2N 118.0W   55 KT  65 MPH
 36H  20/1200Z 19.1N 120.0W   45 KT  50 MPH
 48H  21/0000Z 18.9N 121.7W   35 KT  40 MPH
 72H  22/0000Z 18.6N 124.7W   30 KT  35 MPH
 96H  23/0000Z 18.3N 127.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  24/0000Z 18.0N 129.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
 
$$
FORECASTER BROWN