283 
FXUS66 KPDT 032123
AFDPDT

NORTHEAST OREGON/SOUTHEAST WASHINGTON FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
230 PM PDT MON JUN 3 2002

MODEL DATA CURRENTLY UNDERESTIMATES THE AMPLITUDE OF A RIDGE OF 
HIGH PRESSURE THAT IS CURRENTLY LOCATED JUST OFFSHORE. THIS IS 
SIGNIFICANT BECAUSE THIS SAME RIDGE IS INDUCING A SHORT WAVE TROUGH 
THAT EXTENDS SOUTHEASTWARD INTO CENTRAL OREGON. THE TROUGH IS ADDING 
MILD INSTABILITY TO THE ATMOSPHERE OVER NORTHEASTERN OREGON AND 
SOUTHEASTERN WASHINGTON. FORTUNATELY...THE MOISTURE THAT IS 
AVAILABLE FOR CONVECTION IS EXTREMELY LIMITED AND ANY ISOLATED 
SHOWER ACTIVITY THAT OCCURS THROUGH THIS EVENING WILL FORM AS A 
RESULT OF UPSLOPING. THE RIDGE WILL BUILD INTO THE FORECAST AREA 
OVERNIGHT...AND WILL CONTINUE TO DRY OUT THE AIR MASS OVERHEAD FOR 
TUESDAY. GRADIENT DRIVEN BREEZY TO WINDY CONDITIONS WILL DEVELOP ON 
WEDNESDAY AS AN APPROACHING SYSTEM FROM THE NORTHWEST INDUCES A 
MARINE PUSH. SINCE LITTLE MOISTURE WILL BE PRESENT...NO SIGNIFICANT 
SHOWER OR THUNDERSTORM ACTIVITY IS EXPECTED TUESDAY THROUGH 
WEDNESDAY NIGHT. HENRY.

EXTENDED...ALTHOUGH THE MODELS ARE IN DISAGREEMENT ON TIMING AND 
STRENGTH...TWO SHORT WAVES WILL MOVE THROUGH THE PACIFIC NORTHWEST.  
THE FIRST SHORT WAVE IS VERY WEAK AND WILL MOVE THROUGH ON THURSDAY 
WITH DRY AND COOLER CONDITIONS PREVAILING.  THE SECOND WAVE IS 
STRONGER AND WILL MOVE THROUGH ON FRIDAY INTO SATURDAY WITH A CHANCE 
OF SHOWERS POSSIBLE FOR THE MOUNTAINS.  A RIDGE BUILDS INTO THE 
PACIFIC NORTHWEST BRINGING DRY CONDITION ON SUNDAY AND MONDAY FOR 
OUR FORECAST REGION. PALMER

PDT 0000 ALW -000  PSC 0000  YKM 0000

.KPDT...VCP32/CSR21...OPERATIONAL.  

.KPDT...NONE.