130 PM PST SAT JAN 26 2008 WEATHER SYNOPSIS FOR SATURDAY AND SUNDAY An interesting and complex pattern is shaping up over the Northwest. A front is approaching from over the BC coast Saturday. Moisture is also moving north over Oregon from a low pressure system over the California coast. The front and southern moisture should merge over the Olympics and Cascades on Saturday afternoon and night. This should cause increasing southwest crest level flow and increasing snow Saturday with a slight rise in snow levels. The front should cross the Cascades Saturday evening. An upper trough, weaker flow aloft and cold slightly unstable air mass should move over the Northwest on Sunday. This should lead to decreasing snow showers in the Olympics and Cascades at low snow levels. Crest level winds are indicated to be stronger and snow showers heavier in the south Cascades by Sunday night. WEATHER FORECAST FOR SATURDAY AND SUNDAY * OLYMPICS- Saturday afternoon and night: Increasing moderate to occasional heavy snow. Sunday morning: Decreasing light to moderate snow showers. Sunday afternoon and evening: Mostly light snow showers. * WASHINGTON CASCADES NEAR AND WEST OF THE CREST- Saturday afternoon and night: Increasing moderate to occasional heavy snow. Sunday morning: Decreasing light to moderate snow showers. Sunday afternoon and evening: Mostly light snow showers heaviest south part. * CASCADE PASSES, INCLUDING STEVENS, SNOQUALMIE AND WHITE PASSES- Saturday afternoon: increasing light to moderate snow. Saturday night: Increasing moderate to occasional heavy snow. Sunday morning: Decreasing light to moderate snow showers. Sunday afternoon and evening: Mostly light snow showers heaviest south part. * EAST SLOPES WASHINGTON CASCADES- Saturday afternoon and night: Increasing light to moderate snow. Sunday morning: Decreasing light snow showers heaviest near the crest. Sunday afternoon and evening: Mostly cloudy with light snow showers. * MT HOOD AREA- Saturday afternoon and night: Increasing moderate to heavy snow. Sunday morning: Decreasing light to moderate snow showers. Sunday afternoon and evening: Light to moderate snow showers. SNOW LEVELS-CASCADE MTNS 1000 ft N, 2000 ft C, 3000 ft S Sat aft remaining at the surface Cascade east slopes and passes Lowering Sat eve Near sea level N to C, 1500 ft S Sun morn Near sea level N to C, 1000 ft S Sun aft Near sea level N to S Sun night SNOW LEVELS-OLYMPIC MTNS 1500 ft Sat aft Lowering Sat eve Near sea level Sun and Sun night Cascade Snow/Freezing Levels refer to the northern Washington Cascades (N) through Mt Hood area (S). Central Washington Cascade snow levels (typically near Snoqualmie Pass) are normally midway between indicated N and S levels. Note that surface snow/freezing levels are common near the passes during easterly pass flow and may result in multiple snow/freezing levels. 24 HOUR FORECAST OF PRECIPITATION IN INCHES OF WATER EQUIVALENT ENDING AT 4AM SUN MON * HURRICANE RIDGE .25-.5 .25 * MT BAKER .75 .25-.5 * WASHINGTON PASS .25-.5 .25-.5 * STEVENS PASS .25-.5 .25-.5 * SNOQUALMIE PASS .5-.75 .25-.5 * MISSION RIDGE .25-.5 LT .25 * CRYSTAL MTN .5-.75 .25 * PARADISE .75-1 .25-.5 * WHITE PASS .5 .25-.5 * MT HOOD 1 .5 WINDS IN MILES PER HOUR (MPH) * CASCADE PASS LEVEL WINDS E 5-15 Sat aft Changing Sat eve W 10-20 Sun morn W 5-10 Sun aft and eve * FREE WINDS AT 5000 FT SW 20-30 Sat aft and night strongest south SW 10-20 Sun NE 5-10 N, W 15-25 S Sun night * FREE WINDS AT 9000 FT SW 45-60 Sat aft and night strongest south W 30-40 Sun W 10-20 N, W 25-35 S Sun night EXTENDED WEATHER SYNOPSIS FOR MONDAY THROUGH WEDNESDAY West to northwest crest level flow, a slightly unstable cold air mass, and an west-east Arctic front boundary should be seen over Washington on Monday. This should maintain light snow showers in the north and light to moderate snow showers in the south Monday. A trough in the northwest flow should move over the Northwest Tuesday while a low pressure system moves east along the Arctic front boundary. This should cause increasing light snow showers in the north and moderate to heavy snow showers in the south Tuesday. A short wave ridge should move over the Northwest Wednesday with weak surface high pressure building over the areas. This should lead to decreasing light snow showers Wednesday. EXTENDED FORECAST FOR MONDAY THROUGH WEDNESDAY Monday: Light snow showers north and light to moderate snow showers south. Tuesday: Increasing light snow showers north and moderate to heavy snow showers south. Wednesday: Decreasing light snow showers. * SNOW LEVELS Near sea level N to S Mon to Wed