200 PM PST MON FEB 4 2008 WEATHER SYNOPSIS FOR MONDAY AND TUESDAY After a bit of a break the past couple days and Monday, more strong weather systems should be seen this week. A short wave ridge and weak surface high pressure should cross the Northwest on Monday. However some moisture from a weak system moving over the ridge will affect the Northwest. The moisture should slightly increase later Monday. This should cause increasing light snow Monday afternoon and evening. The next strong system should move across the Northwest on Tuesday. Increasing strong flow aloft should be seen Tuesday over the Olympics and Cascades with a bit of a rise in snow levels. The front should cross the Olympics Tuesday late morning, the north Cascades Tuesday midday, and the south Cascades Tuesday early afternoon. This should cause increasing snow Tuesday. This should be followed west flow aloft, an unstable air mass and orographic snow showers Tuesday afternoon and night at low snow levels. WEATHER FORECAST FOR MONDAY AND TUESDAY * OLYMPICS- Monday afternoon and night: Cloudy with light snow. Tuesday morning: Increasing moderate to heavy snow. Tuesday afternoon and night: Moderate to heavy snow showers. * WASHINGTON CASCADES NEAR AND WEST OF THE CREST- * CASCADE PASSES, INCLUDING STEVENS, SNOQUALMIE AND WHITE PASSES- Monday afternoon and night: Cloudy with light snow especially north. Tuesday morning: Increasing moderate to heavy snow. Tuesday afternoon and night: Moderate to heavy orographic snow showers. * EAST SLOPES WASHINGTON CASCADES- Monday afternoon and night: Increasing clouds especially north and higher elevations. Tuesday morning: Increasing light to moderate snow. Tuesday afternoon and night: Light to moderate snow showers. * MT HOOD AREA- Monday afternoon and night: Cloudy with light snow. Tuesday morning: Increasing moderate snow. Tuesday afternoon and night: Moderate to heavy orographic snow showers. SNOW LEVELS-CASCADE MTNS 1000 ft N, 1500 ft S Mon aft and eve 1500 ft N, 2500 ft C, 4000 ft S Tue morn except surface Cascade passes and east slopes Lowering Tue aft Near sea level N, 1000 ft S Tue night SNOW LEVELS-OLYMPIC MTNS 1500 ft Mon aft and eve 4000 ft Tue morn except surface Cascade passes and east slopes Lowering Tue aft 1000 ft Tue 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 TUE WED * HURRICANE RIDGE .25 1 * MT BAKER .25-.5 1.5-2 * WASHINGTON PASS .25 1 * STEVENS PASS .25 1 * SNOQUALMIE PASS .25 1-1.5 * MISSION RIDGE LT .25 .25-.5 * CRYSTAL MTN LT .25 .75 * PARADISE .25 1.5 * WHITE PASS LT .25 1 * MT HOOD .25 1 WINDS IN MILES PER HOUR (MPH) * CASCADE PASS LEVEL WINDS W 5-15 Mon aft Light variable Mon night E 5-10 Tue morn W 15-25 Tue aft and eve * FREE WINDS AT 5000 FT W 10-20 Mon aft and eve SW 20-30 Tue early morn SW 30-40 Tue lat morn and midday W 25-35 Tue aft and eve * FREE WINDS AT 9000 FT NW 20-30 Mon aft NW 30-40 Mon eve W 30-40 Tue early morn SW 50-60 Tue lat morn and midday W 35-45 Tue aft and eve EXTENDED WEATHER SYNOPSIS FOR WEDNESDAY THROUGH FRIDAY West flow aloft should carry a flat ridge and weak surface high pressure over the Northwest on Wednesday. Orographic snow showers should decrease Wednesday at low snow levels. The next period of very strong west flow and a strong front should begin to affect the Olympics and Cascades Wednesday night. The strongest west flow aloft should be seen as the front crosses the Northwest Thursday morning. Strong west flow and orographic snow showers should follow Thursday afternoon and night. Another weak ridge aloft and higher surface pressure over the Northwest should cause a relative break on Friday. EXTENDED FORECAST FOR WEDNESDAY THROUGH FRIDAY Wednesday morning: Decreasing moderate to heavy snow showers. Wednesday afternoon to Thursday morning: Increasing moderate to heavy snow. Thursday afternoon and night: Moderate to heavy orographic snow showers. Friday: Decreasing snow showers. * SNOW LEVELS 500-1500 ft N, 1-2000 ft S Wed 500-1500 ft N, 15-2500 ft S Thu 1-2000 ft N, 2-4000 ft S Fri