200 PM PST THU FEB 21 2008...corrected time WEATHER SYNOPSIS FOR THURSDAY AND FRIDAY An upper ridge of high pressure continues to move slowly east of the area Thursday afternoon. Most mountain areas have partly cloudy skies with mainly mid or high level clouds Thursday afternoon and moderate temperatures. A strong split in the Pacific westerlies has developed over the eastern north Pacific and should persist for the near future. This is directing the strongest flow and associated weather towards northern and central California, while the Pacific Northwest remains in weak south to southeast flow aloft. This pattern should cause the weakening northern portions of frontal systems should lift over the area and give light amounts of precipitation at times with slightly greater amounts expected in the Mt Hood area nearer the stronger flow. A splitting frontal system is currently moving through northern California and southern Oregon extending offshore and making slow progress northward towards the forecast area. Clouds from this disturbance should spread over the area from the south late Thursday with a little light precipitation spreading northward overnight Thursday. The remnants of the weak northern portion of the front should then slowly lift across the area later Friday and Friday night in a weak upper level flow. This should cause periods of light showers as it weakens and continues northward across the forecast area, mainly Friday night. Freezing levels slowly lower with the passage of the band of moisture Friday night. WEATHER FORECAST FOR THURSDAY AND FRIDAY * OLYMPICS- Thursday aft and eve: Partly sunny with mid or high clouds. Thursday night: Cloudy with a little light rain or snow. Friday: Cloudy with light rain or snow showers, mainly afternoon. Friday night: Cloudy with light rain or snow showers. * WASHINGTON CASCADES- * CASCADE PASSES, INCLUDING STEVENS, SNOQUALMIE AND WHITE PASSES- Thursday aft and eve: Partly sunny with increasing high clouds. Thursday night: Cloudy with a little light rain or snow developing in the south and spreading northward. Friday: Cloudy with light rain or snow showers, mainly south. Friday night: Cloudy with light rain or snow showers. * MT HOOD AREA- Thursday aft and eve: Increasing mid or high clouds. Thursday night: Cloudy with a little light rain or snow. Friday: Cloudy with light rain or snow showers. Friday night: Cloudy with light to occasionally moderate rain or snow. SNOW LEVELS-CASCADE MTNS 3500 ft N, 4500 ft S Thursday aft and eve 3500 ft N and S Thursday night 3000 ft N and S Friday 2500 ft N and S Friday night...except near the surface Cascade east slopes and passes. SNOW LEVELS-OLYMPIC MTNS 4000 ft Thursday aft and eve 3500 ft Thursday night and Friday 3000 ft Friday 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 FRI SAT * HURRICANE RIDGE LT .10 LT .25 * MT BAKER 0 LT .25 * WASHINGTON PASS 0 LT .25 * STEVENS PASS LT .10 LT .25 * SNOQUALMIE PASS LT .10 LT .25 * MISSION RIDGE 0 LT .25 * CRYSTAL MTN LT .10 .25 * PARADISE LT .10 .25 * WHITE PASS LT .10 .25 * MT HOOD LT .10 .25-.5 WINDS IN MILES PER HOUR (MPH) * CASCADE PASS LEVEL WINDS E 5-15 Thursday through Friday night * FREE WINDS AT 5000 FT S 10-20 Thursday aft S-SE 10-20 Thursday night and Friday, strongest south part S-SW 15-30 Friday night, strongest south part * FREE WINDS AT 9000 FT S-SE 15-25 Thursday through Friday morning S-SW 20-30 Friday afternoon and night, strongest south part EXTENDED WEATHER SYNOPSIS FOR SATURDAY THROUGH MONDAY The remnants of a weak moisture band should exit the region to the north early Saturday morning. This should cause a little light rain or snow in the central and north part early Saturday before high pressure again rebuilds over the area. High pressure aloft should gain strength over the Pacific Northwest later Saturday through Monday. A deepening surface low should approach the northern California coast Sunday in a continued split upper level flow. This should maintain mostly fair weather over the northern and central areas later Saturday through Monday with clouds and a little light precipitation possibly reaching the Mt Hood area through the period. EXTENDED FORECAST FOR SATURDAY THROUGH MONDAY Saturday: Light rain or snow showers mainly north part and central ending later Saturday morning. Partly cloudy south. Sunday and Monday: Partly cloudy with occasionally light rain or snow mainly south part. * SNOW LEVELS 15-2500 ft N, 25-3500 ft S Sat 25-3500 ft N, 35-4500 ft S Sun and Mon