Post-Tropical Cyclone IRWIN Forecast Discussion

000
WTPZ41 KNHC 170241
TCDEP1

POST-TROPICAL CYCLONE IRWIN DISCUSSION NUMBER  44
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP112011
800 PM PDT SUN OCT 16 2011

SATELLITE IMAGERY SHOWS THAT IRWIN HAS BEEN VOID OF DEEP CONVECTION
FOR ABOUT 12 HOURS AND THAT THE CIRCULATION HAS WEAKENED AND BECOME
LESS DEFINED.  FOR THESE REASONS...IRWIN NO LONGER QUALIFIES AS A
TROPICAL CYCLONE AND IS BEING DECLARED A REMNANT LOW.  THE SYSTEM
COULD PRODUCE ANOTHER BURST OR TWO OF CONVECTION DURING THE NEXT
DAY OR SO...BUT GIVEN THE AMOUNT OF DRY AIR SURROUNDING THE
LOW IT SHOULD BE VERY SHORT-LIVED.

THE CYCLONE HAS BEEN DRIFTING NORTHWESTWARD DURING THE PAST FEW
HOURS AND THIS GENERAL MOTION SHOULD CONTINUE INTO MONDAY. AFTER
THAT...THE REMNANT LOW IS FORECAST TO TURN SOUTHWARD THEN
SOUTHEASTWARD AS THE LOW-LEVEL FLOW BECOMES NORTHWESTERLY.  THE
UPDATED NHC FORECAST NOW CALLS FOR DISSIPATION WITHIN 72 HOURS.
THIS IS IN GOOD AGREEMENT WITH THE GFS AND ECMWF MODELS...WHICH
BOTH SHOW DISSIPATION IN ABOUT 2 DAYS.

THIS IS THE LAST NHC ADVISORY ON IRWIN.  FOR ADDITIONAL INFORMATION
ON THE REMNANT LOW PLEASE SEE HIGH SEAS FORECASTS ISSUED BY THE
NATIONAL WEATHER SERVICE...UNDER AWIPS HEADER NFDHSFEPI AND WMO
HEADER FZPN02 KWBC.

FORECAST POSITIONS AND MAX WINDS

INIT  17/0300Z 14.1N 108.3W   25 KT  30 MPH...POST-TROP/REMNT LOW
 12H  17/1200Z 14.5N 108.9W   25 KT  30 MPH...POST-TROP/REMNT LOW
 24H  18/0000Z 14.6N 109.3W   25 KT  30 MPH...POST-TROP/REMNT LOW
 36H  18/1200Z 14.4N 109.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
 48H  19/0000Z 14.1N 109.4W   20 KT  25 MPH...POST-TROP/REMNT LOW
 72H  20/0000Z...DISSIPATED

$$
FORECASTER BROWN