215 PM PST MON FEB 11 2008 WEATHER SYNOPSIS FOR MONDAY AND TUESDAY A reduced west flow is now being seen over the northeast Pacific Ocean compared to early February. A moderate front moved over the Northwest on Sunday. This caused rain or snow to change to snow at most locations. Sites at higher elevations near and west of the Cascade crest gained up to a few inches of snow mainly in the central to north Cascades. An upper shortwave ridge should move from over the Northwest coastal waters Monday morning to over the Northwest Monday night. Some warm front moisture should also move over the ridge Monday and affect mainly the Olympics and north Cascades. This should cause increasing light precipitation Monday mainly in the Olympics and north Cascades with a rise in snow levels. The warm front moisture and therefore precipitation should decrease Monday night. The ridge should shift on to the east and increasing southwest flow aloft should be seen over the Northwest Tuesday morning. This should carry a fairly strong cold front across the area Tuesday. The front should cross the Olympics Tuesday midday and the Cascades Tuesday afternoon. This should cause increasing crest level winds and increasing precipitation. A change to northwest flow aloft and a cooler unstable air mass should follow the front. This should cause orographic showers and possible convergence effects Tuesday night. WEATHER FORECAST FOR MONDAY AND TUESDAY * OLYMPICS- Monday: Increasing light rain or snow. Monday night: Decreasing light rain or snow. Tuesday morning: Increasing moderate rain or snow. Tuesday afternoon and night: Light to moderate snow showers. * WASHINGTON CASCADES NEAR AND WEST OF THE CREST- * CASCADE PASSES, INCLUDING STEVENS, SNOQUALMIE AND WHITE PASSES- Monday: Increasing light rain or snow north to central and cloudy with chance of light rain or snow south. Monday night: Decreasing light rain or snow north to central and mostly cloudy south. Tuesday morning: Increasing clouds. Tuesday midday and afternoon: Increasing moderate rain or snow north to central and light to moderate rain or snow south. A little rain or freezing rain changing to snow at the passes. Tuesday night: Light to moderate snow showers. * EAST SLOPES WASHINGTON CASCADES- Monday: Increasing light rain or snow north and increasing clouds central to south. Monday night: Decreasing light rain or snow north and partly cloudy central to south. Tuesday morning: Increasing clouds. Tuesday midday and afternoon: Increasing light to moderate rain or snow north to central and light rain or snow south. Tuesday night: Light snow showers mainly higher elevations. * MT HOOD AREA- Monday: Increasing clouds with slight chance of light rain or snow. Monday night: Mostly cloudy. Tuesday morning: Increasing clouds. Tuesday midday and afternoon: Increasing light to moderate rain or snow. Tuesday night: Light to moderate snow showers. SNOW LEVELS-CASCADE MTNS 3000 ft N, 4000 ft C, 6000 ft S Mon aft and eve 4000 ft N, 6000 ft C, 7000 ft S Tue morn except surface passes and east slopes 2000 ft N, 3000 ft S Tue aft and eve 1000 ft N, 1500 ft S Wed morn SNOW LEVELS-OLYMPIC MTNS 5000 ft Mon aft and eve 6000 ft Tue morn 2500 ft Tue aft and eve 1500 ft Wed 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 TUE WED * HURRICANE RIDGE .25 .5-.75 * MT BAKER .25 .75-1 * WASHINGTON PASS LT .25 .5 * STEVENS PASS LT .25 .5-.75 * SNOQUALMIE PASS .25 .5-.75 * MISSION RIDGE LT .10 LT .25 * CRYSTAL MTN LT .25 .25-.5 * PARADISE .25 .5 * WHITE PASS LT .25 .25-.5 * MT HOOD LT .25 .25-.5 WINDS IN MILES PER HOUR (MPH) * CASCADE PASS LEVEL WINDS W 10-20 Mon morn Light variable Mon aft and eve E 5-10 Tue morn W 10-20 Tue aft W 15-25 Tue night * FREE WINDS AT 5000 FT W 15-25 Mon morn W 10-20 Mon aft to Tue morn SW 35-45 Tue aft W 30-40 Tue night * FREE WINDS AT 9000 FT WNW 30-40 Mon morn W 25-35 Mon aft and eve W 30-40 Tue morn SW 50-70 Tue aft NW 40-60 Tue night EXTENDED WEATHER SYNOPSIS FOR WEDNESDAY THROUGH FRIDAY Another upper ridge should move from over the Northwest coastal waters Wednesday to over the Northwest on Thursday. This should help cause light orographic snow showers to end Wednesday morning. Less cloud cover should be seen by Thursday. A broad ridge should be seen over the northeast Pacific by Friday. A weak front is indicated to move over the ridge and mainly to Canada on Friday. Increasing west flow aloft and moisture from this system should brush mainly the Olympics and north Cascades. EXTENDED FORECAST FOR WEDNESDAY THROUGH FRIDAY Wednesday: Light snow showers near and west of the crest ending in the morning. Mostly cloudy in the afternoon and evening. Thursday: Partly or mostly cloudy especially near and west of the crest. Friday: Light rain or snow Olympics and north Cascades and mostly cloudy south Cascades. * SNOW LEVELS 1-2000 ft N, 15-2500 ft S Wed FREEZING LEVEL Rising to 2-3000 ft N, 5-7000 ft S Thu SNOW LEVELS 2-4000 ft N, 5-7000 ft S Fri