PORTLAND SYNOPSIS...AN UPPER LOW WILL DRIFT SOUTHWARD INTO CALIFORNIA LATER TONIGHT AND EARLY FRIDAY...BUT MAY REMAIN CLOSE ENOUGH TO FEED SOME MOISTURE NORTH INTO OUR FORECAST AREA FOR A FEW SHOWERS OR THUNDERSTORMS AGAIN ON FRIDAY AND SATURDAY. ONSHORE FLOW AND A WEAK SYSTEM MAY SPREAD SOME LIGHT RAIN ONSHORE AGAIN SUNDAY. A WEAK SYSTEM WILL BRUSH THE AREA ON MEMORIAL DAY TO KEEP A FEW SHOWERS AROUND ESPECIALLY NORTH...THEN A BRIEF BREAK IS POSSIBLE AS A WEAK RIDGE BUILDS IN.