100 PM PST SUN DEC 16 2007 WEATHER SYNOPSIS FOR SUNDAY AND MONDAY A moderate front moved across the Northwest early Saturday, causing increased winds, brief warming, and increasing moderate snow to most locations. Snowfall for the 24 hours at NWAC weather stations ending Sunday morning ranges from 16 inches at Mt Baker, to 6-8 inches at Stevens and Snoqualmie, with lighter amounts further south. An active weather pattern is indicated for the Northwest until late in the week. Increasing southwest flow over the Northwest will carry a strong front to the area Sunday afternoon and night. This should cause increasing southwest crest level winds and increasing snow Sunday afternoon and especially Sunday night which will initially favor the volcanoes. Offshore surface flow will limit snowfall at the passes Sunday afternoon. This should be followed by heavy orographic snow showers Sunday around midnight through Monday morning. A convergence and heavier snowfall is also indicated near Glacier Peak by the MM5 model Monday late morning. A brief short wave ridge and temporary surface high pressure should move to over the Northwest Monday afternoon and evening. This should bring a little break and cause snow showers to decrease and become light Monday afternoon and night. WEATHER FORECAST FOR SUNDAY AND MONDAY * OLYMPICS- Sunday afternoon and evening: Increasing heavy snow heaviest southwest Olympics. Sunday night and Monday morning: Heavy snow showers heaviest west Olympics. Monday afternoon: Decreasing light to moderate snow showers heaviest west Olympics. Monday evening: Light snow showers. * WASHINGTON CASCADES NEAR AND WEST OF THE CREST- Sunday afternoon: Increasing moderate to heavy snow. Sunday night: Increasing heavy snow. Monday morning: Heavy snow showers. Monday afternoon: Decreasing light to moderate snow showers. Monday evening: Light snow showers. * WASHINGTON CASCADES NEAR AND WEST OF THE CREST-CASCADE PASSES INCLUDING STEVENS, SNOQUALMIE AND WHITE PASSES- Sunday afternoon: Increasing light to moderate snow. Sunday night: Increasing heavy snow. Monday morning: Heavy snow showers. Monday afternoon: Decreasing light to moderate snow showers. Monday evening: Light snow showers. * EAST SLOPES WASHINGTON CASCADES- Sunday afternoon: Increasing light snow. Sunday night: Increasing moderate snow. Monday morning: Moderate snow showers most locations. Monday afternoon: Decreasing light snow showers. Monday evening: Partly or mostly cloudy with light snow showers. * MT HOOD AREA- Sunday afternoon: Increasing light to moderate snow. Sunday night: Increasing heavy snow. Monday morning: Decreasing moderate snow showers. Monday afternoon: Decreasing light snow showers. Monday evening: Light snow showers. SNOW LEVELS-CASCADE MTNS 2000 ft N, 2500 ft C, 3000 ft S Sun aft 1500 ft N, 2000 ft C, 2500 ft S Sun night 1000 ft N, 2000 ft S Mon morn 1000 ft N, 1500 ft S Mon aft and eve except near the surface Cascade passes and east slopes Sunday. SNOW LEVELS-OLYMPIC MTNS 2500 ft Sun aft and Sun eve 1000 ft Mon morn 1500 ft Mon 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 MON TUE * HURRICANE RIDGE .75-1 .5 * MT BAKER 1 .75 * WASHINGTON PASS .25-.5 .25-.5 * STEVENS PASS .5 .5 * SNOQUALMIE PASS .5 .5-.75 * MISSION RIDGE .25 .25 * CRYSTAL MTN .5 .25-.5 * PARADISE .75-1 .75 * WHITE PASS .5 .25-.5 * MT HOOD .75-1 .5 WINDS IN MILES PER HOUR (MPH) * CASCADE PASS LEVEL WINDS E 10-20 Sun aft and eve W 10-20 Sun night and Mon morn W 5-15 Mon aft Light variable Mon night * FREE WINDS AT 5000 FT SW 30-40 Sun aft strongest Olympics SW 40-50 Sun night W 30-40 Mon morn SW 15-25 Mon aft and eve * FREE WINDS AT 9000 FT SW 40-50 Sun aft strongest Olympics SW 50-60 Sun night W 40-50 Mon morn SW 25-35 Mon aft and eve EXTENDED WEATHER SYNOPSIS FOR TUESDAY THROUGH THURSDAY The active weather pattern for the Northwest should continue much of the week. Increasing southwest flow aloft should carry another front over the Northwest Tuesday midday. This should cause increasing snow Tuesday morning followed by orographic snow showers Tuesday afternoon. Another relative break should be seen Tuesday night to Wednesday morning. Increasing west to southwest flow aloft should carry yet another front over the Northwest about Wednesday afternoon. This should again cause increasing snow Wednesday afternoon and night followed by orographic snow showers Thursday morning. Snow showers should end late Thursday as an upper ridge moves to over the coastal waters and surface high pressure builds over the Northwest. EXTENDED FORECAST FOR TUESDAY THROUGH THURSDAY Tuesday morning: Increasing snow becoming moderate north and heavy south. Tuesday afternoon and evening: Moderate to heavy orographic snow showers. Tuesday night: Decreasing orographic snow showers. Wednesday morning: Light snow showers. Wednesday afternoon and evening: Increasing moderate to heavy snow. Thursday morning: Moderate to heavy orographic snow showers. Thursday afternoon: Decreasing orographic snow showers. Thursday night: Light snow showers. * SNOW LEVELS 1-2000 ft N and S Tue 1-2000 ft N, 2-4000 ft S Wed except near the surface Cascade passes and east slopes 1-2000 ft N and S Thu