FXUS66 KPDT 210312
AFDPDT

NORTHEAST OREGON/SOUTHEAST WASHINGTON FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
815 PM PDT WED AUG 20 2003

CLEAR SKIES AND LIGHT WINDS WILL DOMINATE UNDER A HIGH PRESSURE 
RIDGE OVER THE PACIFIC NORTHWEST TONIGHT.  THE HIGH PRESSURE OVER 
THE SOUTH-CENTRAL U.S. COMBINED WITH AN APPROACHING LOW PRESSURE 
SYSTEM OFF THE CALIFORNIA COAST WILL BRING A DEEP SOUTHERLY FLOW TO 
THE FORECAST AREA THURSDAY AND FRIDAY.  ABUNDANT MONSOON MOISTURE 
FROM THE DESERT SOUTHWEST WILL BE CONVEYED NORTHWARD INTO THE 
PACIFIC NORTHWEST IN THIS SOUTHERLY FLOW.  THE MOISTURE WILL FIRST 
REACH THE SOUTHERN AREAS OF THE CWA...MAINLY FROM MADRAS-JOHN DAY 
SOUTHWARD ON THURSDAY.  THEN THE MOISTURE WILL SPREAD INTO THE 
REMAINDER OF OREGON AND INTO WASHINGTON ON FRIDAY.  THE ATMOSPHERE
WILL REMAIN FAIRLY STABLE ON THURSDAY SO ONLY EXPECT A SLIGHT THREAT 
OF SHOWERS AND THUNDERSTORMS IN THE SOUTHWEST PORTION OF THE CWA.  
THEN FRIDAY THE ATMOSPHERE WILL BECOME UNSTABLE WITH THE MOST 
INSTABILITY OCCURRING IN THE AFTERNOON AT THE TIME OF MAXIMUM 
HEATING OF THE DAY.  AT THAT SAME TIME A WEATHER DISTURBANCE WILL 
MOVE ACROSS THE AREA TO PROVIDE A TRIGGER FOR THUNDERSTORMS.  AS 
SUCH CAN EXPECT A POSSIBILITY OF STRONG THUNDERSTORMS WITH GUSTY 
WINDS AND HEAVY RAIN.  SOME STORMS INITIALLY MAY BE DRY...BUT DUE TO 
THE ABUNDANT MOISTURE THAT WILL BE FED INTO THE FORECAST AREA DO NOT 
EXPECT SIGNIFICANT DRY LIGHTNING NOR A SIGNIFICANT FIRE THREAT AT 
THIS TIME.  RSC.

PDT 0000  ALW 0000  PSC 0000  YKM 0000

.KPDT...NONE.
   
$$