AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PENDLETON OR 227 PM PST TUE JAN 20 2015 .SHORT TERM...TONIGHT THROUGH THURSDAY...A RIDGE OF UPPER LEVEL HIGH PRESSURE BUILDING ALONG 130W WILL SHIFT EAST TONIGHT AND WEDNESDAY, REACHING A POSITION OVERHEAD BY WEDNESDAY AFTERNOON. THIS RIDGE WILL KEEP THE REGION DRY TONIGHT THROUGH WEDNESDAY EVENING. INVERSIONS OVER THE COLUMBIA BASIN AND SURROUNDING VALLEYS ARE EXPECTED TO STRENGTHEN OVERNIGHT INTO WEDNESDAY MORNING. THUS WITH CLEARER SKIES TONIGHT, EXPECT BETTER FOG AND LOW CLOUD DEVELOPMENT IN THESE AREAS. THUS WILL CONTINUE TO SHOW THE DEVELOPMENT AND EXPANSION OF FOG AND LOW CLOUDINESS ACROSS THE BASIN AND SURROUNDING VALLEYS TONIGHT INTO WEDNESDAY MORNING. THERE IS THE POSSIBILITY THAT SOME LOCATIONS, PARTICULARLY THOSE ABOVE 1500 FEET MSL COULD REQUIRE DENSE OR FREEZING FOG ADVISORIES. AS AM CURRENTLY UNCERTAIN WHERE EXACTLY THE DENSEST FOG WILL BE, WILL HOLD OFF ON ANY ADVISORIES AT THIS TIME. A PACIFIC SYSTEM WILL MOVE INTO AND FLATTEN THE UPPER RIDGE LATE WEDNESDAY NIGHT INTO THURSDAY. THIS SYSTEM WILL BE GENERALLY WEAK, BUT WILL BRING SOME LIGHT PRECIP TO THE AREA. BEST CHANCES WILL BE ALONG THE WASHINGTON CASCADE CREST. SNOW LEVELS LOOK TO RISE WEDNESDAY NIGHT WHILE LOW TEMPS WILL BE AT OR SLIGHTLY BELOW FREEZING. TIMING OF PRECIP ARRIVING WHILE THE COOL MORNING LOWS ARE STILL OCCURRING FAVORS OUR SOUTH-CENTRAL WASHINGTON ZONES. THUS WILL CONTINUE TO MENTION CHANCES OF FREEZING RAIN AS WELL AS RAIN AND HIGHER LEVEL SNOW OVER THIS PORTION OF THE AREA THURSDAY MORNING.
Posted on: Tue, 20 Jan 2015 23:07:40 +0000