FXUS66 KPQR 162133
AFDPQR

NORTHWEST OREGON AND SOUTHWEST WASHINGTON FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
230 PM PST SUN MAR 16 2003

.SYNOPSIS...A BROAD UPPER LEVEL TROUGH OVER THE EAST PACIFIC WILL
MAINTAIN A MOIST SOUTHWEST FLOW ALOFT OVER THE FORECAST AREA FOR THE
NEXT SEVERAL DAYS. THE AIR MASS IS UNSTABLE THIS AFTERNOON WITH AREAS
OF SHOWERS AND ISOLATED THUNDERSTORMS SHOWING UP ON NATIONAL WEATHER
SERVICE RADAR. A WEAK PACIFIC COLD FRONT WILL MOVE INLAND OVER THE
FORECAST AREA ON MONDAY AND ANOTHER TUESDAY. A STRONGER COLD FRONT
WILL MOVE INLAND ACROSS THE AREA ON WEDNESDAY. A SERIES OF PACIFIC
WEATHER SYSTEMS WILL PARADE INLAND ACROSS THE FORECAST AREA NEXT
WEEK.

.DISCUSSION...
.SHORT TERM...A BROAD 500 MILLIBAR TROUGH OVER THE EASTERN PACIFIC
WILL MAINTAIN SOUTHWEST FLOW ALOFT OVER THE PACIFIC NORTHWEST AS IT
ROTATES WEAK SHORE WAVES INLAND OVER THE FORECAST AREA. SEVERAL WEAK
VORTICITY LOBES ARE VISIBLE OVER THE FORECAST AREA ON INFRA RED
SATELLITE IMAGERY THIS AFTERNOON. THESE WILL ADD AN ADDITION
TRIGGER TO DAYTIME HEATING FOR CONVECTION IN A CONDITIONALLY UNSTABLE
AIR MASS THIS AFTERNOON AND EVENING. ONE VORTICITY LOBE TRIGGERED A
FEW STRIKES OVER THE NORTHWEST CORNER OF OREGON ALREADY THIS
AFTERNOON. THIS AREAS WILL  BECOME ACTIVE THORUGH THIS EVENING WITH
SHOWERS AND A CHANCE OF A THUNDERSTORM. A WEAK SHORTWAVE AND FRONT
WILL MOVE INLAND MONDAY THEN A ANOTHER WEAK FRONT WILL BRUSH ACROSS
NORTHWEST OREGON ON TUESDAY. THE UPPER LEVEL TROUGH WILL COME INLAND
WITH A STRONGER FRONT ON WEDNESDAY BUT IT WILL BE SPLITTING AS IT
COMES WITH THE HEAVIEST PRECIPITATION MOVING INTO CALIFORNIA AND
BRITISH COLUMBIA.

.LONG TERM...A PROGRESSIVE PATTERN CONTINUES LIKELY PRECIPITATION FOR
THE EXTENDED PERIOD AS SYSTEMS MOVE THROUGH ABOUT EVERY 24 HOURS.
WILLSON

AST 775777  PDX 775556  SLE 775555  EUG 775554

.PQR...SMALL CRAFT ADVISORY CAPE SHOALWATER TO FLORENCE FOR 
       HAZARDOUS SEAS..

$$