130 PM PST SUN MAR 2 2008 WEATHER SYNOPSIS FOR SUNDAY AND MONDAY A front crossed the Northwest late Friday. This was followed by an upper trough, a cooler slightly unstable air mass and orographic west flow on Saturday. This caused 2 day snowfall totals of about 10-20 inches at sites near and west of the crest with a little less at lower elevation sites. Northwest flow decreased and orographic showers ended Sunday morning. A ridge, surface high pressure and drier air mass should shift east over the Northwest on Sunday afternoon and evening. This should bring fair weather to most of the Cascades. Some high clouds are indicated for the Olympics and north Cascades. A front and shortwave trough should move over the ridge and over the Northwest on Monday. This should begin to spread more clouds to the Olympics and north Cascades Sunday night. Increasing southwest crest level flow and increasing precipitation should be seen Monday initially in the Olympics and north Cascades. The front should cross the Olympics Monday late morning and the Cascades Monday afternoon. The front should be followed with west orographic crest level flow and a slightly unstable air mass Monday night with convergence effects likely in the north to central Cascades. This front is indicated to cause the most precipitation in the Olympics and north to central Cascades. WEATHER FORECAST FOR SUNDAY AND MONDAY * OLYMPICS- Sunday afternoon: Partly sunny with some high clouds. Sunday night: Increasing clouds. Monday morning: Light rain or snow developing. Monday afternoon: Moderate to heavy rain or snow heaviest southwest part. Monday night: Moderate to heavy snow showers heaviest west part. * WASHINGTON CASCADES NEAR AND WEST OF THE CREST- * CASCADE PASSES, INCLUDING STEVENS, SNOQUALMIE AND WHITE PASSES- Sunday afternoon: Some high clouds north and partly or mostly sunny central and south. Sunday night: Increasing clouds especially north part. Monday morning: Further increasing clouds with light rain or snow north part. Monday afternoon: Moderate to heavy rain or snow north to central part and light to moderate rain or snow south part. Monday night: Moderate to heavy snow showers north to central part and light to moderate snow showers south part. * EAST SLOPES WASHINGTON CASCADES- Sunday afternoon: Mostly sunny. Sunday night: Partly or mostly clear. Monday morning: Increasing clouds initially north part. Monday afternoon: Light to moderate rain or snow heaviest north to central part. Monday night: Light to moderate snow showers mainly higher elevations and heaviest north to central part. * MT HOOD AREA- Sunday: Mostly sunny. Sunday night: Mostly clear. Monday morning: Increasing clouds. Monday afternoon: Light to moderate rain or snow. Monday night: Light to moderate snow showers. FREEZING LEVELS-CASCADE MTNS 2000 ft N, 3000 ft S Sun morn 3000 ft N, 4000 ft S Sun aft and eve SNOW LEVELS 2000 ft N, 2500 ft C, 6000 ft S Mon morn 1500 ft N, 3000 ft S Mon aft and eve 1000 ft N, 2000 ft S Tue morn FREEZING LEVELS-OLYMPIC MTNS 2500 ft Sun morn 3500 ft Sun aft and eve SNOW LEVELS 3500 ft Mon morn 2000 ft Mon aft and eve 1500 ft Tue morn 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 LT .10 .5-.75 * MT BAKER LT .10 .75-1 * WASHINGTON PASS 0 .5-.75 * STEVENS PASS 0 .5-.75 * SNOQUALMIE PASS 0 .75 * MISSION RIDGE 0 LT .25 * CRYSTAL MTN 0 .25-.5 * PARADISE 0 .5-.75 * WHITE PASS 0 .25-.5 * MT HOOD 0 .25-.5 WINDS IN MILES PER HOUR (MPH) * CASCADE PASS LEVEL WINDS W 10-15 Sun morn Light variable Sun aft and eve E 5-15 Mon morn Becoming W 15-30 Mon aft and eve * FREE WINDS AT 5000 FT NW 10-20 Sun morn W 5-15 Sun aft and eve SW 20-30 Mon morn strongest Olympics W 30-40 Mon aft and eve * FREE WINDS AT 9000 FT NW 20-30 Sun morn W 15-25 Sun aft and eve SW 25-50 Mon morn strongest Olympics and north Cascades W 50-60 Mon aft and eve EXTENDED WEATHER SYNOPSIS FOR TUESDAY THROUGH THURSDAY The upper ridge and surface high pressure should build and shift east over the Northwest from Tuesday to Thursday morning. This should cause a period of fair weather. A series of systems in a more active flow is indicated to approach later Thursday. The first weak front of these systems is indicated to brush mainly the Olympics and north Cascades later Thursday. EXTENDED FORECAST FOR TUESDAY THROUGH THURSDAY Tuesday morning: Scattered light showers mainly near and west of the crest ending. Tuesday afternoon to Thursday morning: Partly or mostly sunny days and partly or mostly clear nights. Thursday afternoon and night: Light rain or snow mainly Olympics and north Cascades. * FREEZING LEVELS Rising to 2-3000 ft N, 3-4000 ft S by later Tue Further rising to 5-7000 ft N, 7-9000 ft S by later Wed SNOW LEVELS Lowering to 5-6000 ft N, 6-8000 ft S Thu