200 PM PST FRI FEB 15 2008 WEATHER SYNOPSIS FOR FRIDAY AND SATURDAY The main position of a broad upper ridge of high pressure remains over the eastern north Pacific Friday afternoon, despite a weak frontal system transiting the ridge and approaching the area. The weakening disturbance is moving into the Olympics Friday afternoon and has spread light precipitation from Mt Baker in the north to Snoqualmie Pass. The weak front should transit the area overnight and produce a period of generally light precipitation with briefly moderate precipitation in the north and gradually lesser amounts to the south and little or no precipitation reaching the Mt Hood area. High freezing levels early Friday under the ridge should lower gradually by early Saturday with the passage of the accompanying upper disturbance. The flow becomes northerly later Saturday as upper level high pressure re-establishes and strengthens over the region. The strong upper ridge is expected to gradually shift inland later Saturday. Following some low clouds early Saturday as the weak disturbance exits the area; the Pacific Northwest should be left with just high clouds later Saturday. Skies clear late Saturday and freezing levels rise as the upper ridge continues to build over the area. WEATHER FORECAST FOR FRIDAY AND SATURDAY * OLYMPICS- Friday afternoon: Light rain or snow at times. Friday night: Decreasing light rain or snow showers. Early Saturday: Mostly cloudy with a chance of a few light snow showers. Late Saturday: Becoming partly cloudy with mainly high clouds. * WASHINGTON CASCADES NEAR AND WEST OF THE CREST NORTH OF STEVENS PASS- * CASCADE PASSES NORTH OF STEVENS PASS Friday afternoon and evening: Light to occasionally moderate rain or snow at times. Friday night: Decreasing light rain or snow showers. Early Saturday: Mostly cloudy with a chance of a few light snow showers. Late Saturday: Becoming partly cloudy with mainly high clouds. * WASHINGTON CASCADES NEAR AND WEST OF THE CREST FROM STEVENS PASS SOUTHWARD TO MT RAINIER- * CASCADE PASSES FROM STEVENS PASS SOUTHWARD TO MT RAINIER, INCLUDING STEVENS AND SNOQUALMIE PASSES- Friday afternoon and evening: Light rain or snow. Friday night: Decreasing light rain or snow showers. Early Saturday: Mostly cloudy. Late Saturday: Becoming partly cloudy with mainly high clouds. * WASHINGTON CASCADES NEAR AND WEST OF THE CREST FROM MT RAINIER SOUTHWARD- * CASCADE PASSES FROM STEVENS PASS SOUTHWARD TO MT RAINIER, INCLUDING WHITE PASS- Friday afternoon: Lowering clouds with light rain or snow showers developing. Friday night: Occasional light rain or snow showers. Early Saturday: Mostly cloudy. Late Saturday: Becoming partly cloudy with mainly high clouds. * EAST SLOPES WASHINGTON CASCADES- Friday afternoon: Mid and high clouds increasing. Friday night: Occasional light rain or snow showers, mainly higher elevations nearer the crest. Early Saturday: Mostly cloudy. Late Saturday: Becoming partly cloudy with mainly high clouds. * MT HOOD AREA- Friday afternoon: Lowering clouds. Friday night: Chance of a few light rain or snow showers. Early Saturday: Mostly cloudy. Late Saturday: Becoming partly cloudy with mainly high clouds. SNOW LEVELS-CASCADE MTNS 3500 ft N, 4500 ft C, 7000 ft S Friday afternoon 2500 ft N, 3500 ft C, 5000 ft S Friday night and Saturday morning FREEZING LEVELS-CASCADE MTNS 3500 ft N and C, 7000 ft S Saturday afternoon 6000 ft N, 9000 ft S Saturday night SNOW LEVELS-OLYMPIC MTNS 4500 ft Friday afternoon 3500 ft Friday night and early Saturday FREEZING LEVELS-OLYMPIC MTNS 4000 ft Saturday afternoon 8000 ft Saturday 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 SAT SUN * HURRICANE RIDGE LT .10 0 * MT BAKER .25-.5 0 * WASHINGTON PASS LT .25 0 * STEVENS PASS LT .25 0 * SNOQUALMIE PASS LT .25 0 * MISSION RIDGE LT .10 0 * CRYSTAL MTN LT .25 0 * PARADISE LT .25 0 * WHITE PASS LT .10 0 * MT HOOD LT .10 0 WINDS IN MILES PER HOUR (MPH) * CASCADE PASS LEVEL WINDS W 5-15 Friday afternoon and night W 0-10 Saturday morning Var 0-10 Saturday afternoon E 0-10 Saturday night * FREE WINDS AT 5000 FT W 15-25 Friday afternoon W-NW 10-20 N, 15-25 S Friday night NW 10-20 Saturday N 5-15 Saturday night * FREE WINDS AT 9000 FT W-SW 15-30 mid-day Friday W 25-40 Friday afternoon NW 25-35 Friday night N 15-25 Saturday and Saturday night EXTENDED WEATHER SYNOPSIS FOR SUNDAY THROUGH TUESDAY The building upper level ridge offshore should gradually move over the area Sunday and Monday. This should allow for clearing and significantly warmer weather. The highest freezing levels of the winter are expected later Sunday and Monday with weak flow over the area. Easterly surface flow across the passes should maintain a weak inversion but still mild temperatures at the passes as well later Sunday and Monday. A weakening and splitting frontal system should move across the area Tuesday to cause a little light precipitation at lowering freezing levels and increasing winds. EXTENDED FORECAST FOR SUNDAY THROUGH TUESDAY Sunday: A few high clouds otherwise mostly fair and warm higher terrain; partly cloudy and cooler near the Cascade passes with increasing east winds Monday: Mostly sunny days and fair nights and warm. Early Tuesday: Increasing mid and high clouds. Late Tuesday: Light rain or snow at times. * FREEZING LEVELS 6-8000 ft N, 7-9000 ft C, 9-11,000 ft S Sunday morning 8-10,000 ft N and C, 9-11,000 ft S Sunday afternoon through Monday morning 6-8000 ft N, 7-9000 ft C, 8-10,000 ft S Monday afternoon and night, except locally cooler near the Cascade passes Sunday and Monday * SNOW LEVELS 3-5000 ft N, 4-6000 ft S early Tuesday 2-4000 ft N, 3-5000 ft S late Tuesday