130 PM PST FRI JAN 25 2008 WEATHER SYNOPSIS FOR FRIDAY AND SATURDAY Moderate west flow will be over Canada on Friday, with a low pressure system over the California coastal waters. The Northwest should remain between these features under an area of weak flow aloft and weak surface high pressure. This should bring one more day of fair cool weather to the Olympics and Cascades on Friday. A weak northern front approaching from over the BC coast and southern moisture from the California low should begin to merge over the Northwest Saturday. This should begin to cause increasing clouds Friday night and Saturday morning. The front and moisture should continue to merge as the front moves over the Olympics and Cascades Saturday afternoon and evening. This should cause increasing crest level flow and increasing snow with a slight rise in snow levels. Offshore surface flow may limit snowfall in the passes until a change to onshore surface flow early Sunday. WEATHER FORECAST FOR FRIDAY AND SATURDAY * OLYMPICS- Friday afternoon: Sunny. Friday night: Becoming partly cloudy. Saturday morning: Further increasing clouds. Saturday midday and afternoon: Increasing light snow. Saturday night: Increasing moderate snow possibly heaviest south Olympics. * WASHINGTON CASCADES NEAR AND WEST OF THE CREST- Friday afternoon: Sunny. Friday night: Becoming partly cloudy north and remaining mostly clear south. Saturday morning: Further increasing clouds. Saturday afternoon: Increasing light snow. Saturday night: Increasing moderate snow possibly heaviest central to south part. * CASCADE PASSES, INCLUDING STEVENS, SNOQUALMIE AND WHITE PASSES- Friday afternoon: Sunny. Friday night: Becoming partly cloudy mainly Stevens and possibly Snoqualmie and remaining mostly clear White. Saturday morning: Further increasing clouds. Saturday afternoon: Increasing light snow. Saturday night: Increasing light to moderate snow. * EAST SLOPES WASHINGTON CASCADES- Friday afternoon: Sunny. Friday night: Becoming partly cloudy north and remaining mostly clear south. Saturday morning: Further increasing clouds. Saturday afternoon: Increasing light snow. Saturday night: Increasing light to moderate snow possibly heaviest central to south part. * MT HOOD AREA- Friday afternoon: Sunny. Friday night: Mostly clear. Saturday morning: Increasing clouds. Saturday afternoon: Increasing light snow. Saturday night: Increasing moderate snow. FREEZING LEVELS-CASCADE MTNS Near sea level N to C, 5000 ft S Fri aft and eve SNOW LEVELS Near sea level N to C, 5000 ft S Sat morn 1000 ft N, 2000 ft C, 3000 ft S Sat aft and eve remaining at the surface Cascade east slopes and passes Sat and Sat eve FREEZING LEVELS-OLYMPIC MTNS 3000 ft Fri aft and eve SNOW LEVELS Near sea level Sat morn 1500 ft Sat aft and eve 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 SAT SUN * HURRICANE RIDGE 0 .25-.5 * MT BAKER 0 .5 * WASHINGTON PASS 0 .25-.5 * STEVENS PASS 0 .25 * SNOQUALMIE PASS 0 .25-.5 * MISSION RIDGE 0 LT .25 * CRYSTAL MTN 0 .25-.5 * PARADISE 0 .5 * WHITE PASS 0 .25-.5 * MT HOOD 0 .5 WINDS IN MILES PER HOUR (MPH) * CASCADE PASS LEVEL WINDS E 5-15 Fri aft E 5-10 Fri night E 0-10 Sat Changing Sat eve W 10-20 Sun morn * FREE WINDS AT 5000 FT WSW 0-10 Fri aft and eve WSW 15-25 Sat morn strongest south WSW 20-30 Sat aft and eve strongest south * FREE WINDS AT 9000 FT WSW 10-20 Fri aft and eve WSW 30-40 Sat morn strongest south WSW 40-60 Sat aft and eve strongest south EXTENDED WEATHER SYNOPSIS FOR SUNDAY THROUGH TUESDAY An upper trough with weak flow and a cold slightly unstable air mass should move over the Northwest on Sunday. This should cause decreasing snow showers mainly near and west of the crest with a return snow levels near sea level. A northwest flow should become established over the Northwest on Monday and Tuesday, with an west-east Arctic front boundary over Washington. Weak waves in this flow are currently indicated which should cause increased snow at times Monday and Tuesday. EXTENDED FORECAST FOR SATURDAY THROUGH MONDAY Sunday and Sunday night: Decreasing mostly light snow showers mainly near and west of the crest. Monday and Tuesday: Periods of light occasional moderate snow mainly near and west of the crest. * SNOW LEVELS Near sea level N to S Sun to Tue