Mountain Weather Forecast
Northwest Weather and Avalanche Center Seattle Washington
1334 PM PST Fri Feb 03 2012
The NWAC program is administered by the USDA-Forest Service and operates out of the National Weather Service Forecast Office in Seattle. NWAC services are made possible by important collaboration and support from a wide variety of federal, state and private cooperators.
Weather Synopsis for Friday and Saturday
The second strong ridge of the winter has formed over the area; the first strong ridge was back in December and early January. The ridge extends from California to BC on Friday and should expand to the east along the International border on Saturday. A low pressure system should weaken as it moves north to the Gulf of Alaska on Friday; well to the west of our area. A second weaker system should do similar on Saturday and Sunday.
The ridge will cause mostly weak flow and warm temperatures aloft over the Northwest Friday and Saturday. The GFS and WRF models indicated slightly stronger southeast crest level flow and slightly stronger offshore surface pressure gradients through Friday morning which are persisting into Friday afternoon. So strong southeast wind should be seen at Crystal and strong east pass winds should be seen mainly at Snoqualmie through Friday afternoon. Temperature and minor moisture inversion conditions are also likely again Saturday morning in the Cascade passes and east of the crest.
Weather Forecast for Friday and Saturday
Olympics
| Time | Weather |
| Friday and Saturday: |
Mostly sunny and mostly clear and warmer especially at higher elevations. Cooler in the lower valleys especially night and morning hours. |
Washington Cascades near and west of the crest
Stevens, Snoqualmie and White Passes
| Time | Weather |
| Friday and Saturday: |
Mostly sunny and mostly clear and warmer at higher elevations. Cooler in the passes especially night and morning hours. Gusty east winds west approach to Snoqualmie through Friday afternoon then gradually decreasing. |
East slopes Washington Cascades
| Time | Weather |
| Friday and Saturday: |
Mostly sunny and mostly clear and warmer at higher elevations. Cool in lower valleys especially night and morning hours. |
Mt Hood area
| Time | Weather |
| Friday and Saturday: |
Mostly sunny and mostly clear and warmer at higher elevations. |
Snow Level/Freezing Level Trends in feet
FREEZING LEVELS
Olympics, Cascades--Mt Baker (N) to Snoq Pass (C) to Mt Hood (S)
| Time | Olympics | North | Central | South |
| Friday afternoon through Saturday morning: | 10000 | 10000 | 10000 | 10000 |
| Saturday afternoon: | 9000 | 9000 | 9000 | 9000 |
| Satuday night: |
8000 |
8000 | 8000 | 8000 |
Except at the surface in the lower Cascade passes and east slopes especially night and morning hours.
Cascade Snow / Freezing Levels noted above refer to the north (approximately Mt Baker and Washington Pass), central (approximately Stevens and Snoqualmie Pass) and south (near Mt Hood). Note that surface snow levels are common near the passes during easterly pass flow and may result in multiple snow / freezing levels.
Quantitative Precipitation
24 hour forecast of precipitation in inches of water (rain) equivalent (WE) ending at 4AM of indicated day
| Location W.E. for 24 hours ending at 4AM on... | Saturday | Sunday |
| Hurricane Ridge | 0 |
0 |
| Mt Baker Ski Area |
0 |
0 |
| Washington Pass | 0 |
0 |
| Stevens Pass | 0 |
0 |
| Snoqualmie Pass | 0 |
0 |
| Mission Ridge | 0 |
0 |
| Crystal Mt | 0 |
0 |
| Paradise | 0 |
0 |
| White Pass | 0 |
0 |
| Mt Hood Meadows |
0 |
0 |
| Timberline | 0 |
0 |
LT = less than; WE or Water equivalent is the liquid water equivalent of melted snow in hundredths of inches. As a rough approximation 1 inch of snow = about .10 inches WE, or 10 inches of snow = about 1 inch WE.
Winds in Miles per Hour (MPH) "Cascade Pass Level Winds"
| Time | Direction - Speed |
| Friday afternoon: |
E 20-30 |
| Friday night to Saturday morning: |
E 15-25 |
| Saturday afternoon and night: |
E 10-20 |
Directions above indicate the direction the wind blows from on the 16-point cardinal scale. Winds near the passes tend to be highly channeled by the topography and normally blow either easterly or westerly depending on the surface pressure gradients that drive such winds.
Free Winds at 5000 FT (in Miles per Hour (MPH))
| Time | Olympics | Cascades North |
Cascades Central | Cascades South |
| Friday afternoon: |
SE 15 |
SE 10 |
SE 30 |
SE 10 |
| Friday night: |
SE 15 |
SE 10 |
SE 15 | SE 10 |
| Saturday and Saturday night: |
SE 10 |
SE 5 |
SE 5 | SE 5 |
Directions above indicate the direction the wind blows from on the 16-point cardinal scale. These winds and the 9000 ft winds below also indicate "free" winds, or those winds in the atmosphere not influenced by terrain. Topographical effects may produce greater or lower wind speeds in certain locations as well as significant variations in direction.
Free Winds at 9000 FT (in Miles per Hour (MPH))
| Time | Olympics | Cascades North |
Cascades Central |
Cascades South |
| Friday afternoon: |
SE 20 |
SE 10 |
SE 20 |
SE 10 |
| Friday night: | SSW 15 | SSW 10 | SSW 10 | SSW 10 |
| Saturday: |
SSE 10 |
SSE 5 |
SSE 5 |
SSE 5 |
| Saturday night: |
SSW 10 |
SSW 5 |
SSW 5 |
SSW 5 |
Directions above indicate the direction the wind blows from on the 16-point cardinal scale. These winds and the 9000 ft winds below also indicate "free" winds, or those winds in the atmosphere not influenced by terrain. Topographical effects may produce greater or lower wind speeds in certain locations as well as significant variations in direction.
Extended Weather Synopsis for Sunday through Tuesday
The strong ridge should remain over the California to BC area Sunday and Monday extending also the the east over the International border. The second weaker low pressure system should move north to Alaska on Sunday again well to the west of our area. This should continue to cause weak flow and warm temperatures aloft Sunday and Monday. Temperature and minor moisture inversion conditions are also likely Friday and Saturday especially in the Cascade passes and east of the crest.
The GFS model indicates that a system will split over the northeast Pacific Ocean on Tuesday with the south part of the system reaching the Northwest later Tuesday. Some light precipitation is indicated to spread from southwest to northeast over the Northwest. Given the strength of the ridge this system may just turn out to be clouds over the Northwest but for now a chance of light precipitation and lower snow levels will be indicated in the forecast.
Extended Weather Forecast for Sunday through Tuesday
Olympics, Washington Cascades & Mt Hood Area
| Time | Weather |
| Sunday and Monday: |
Mostly sunny and mostly clear and warmer at higher elevations. |
| Tuesday morning: |
Increasing mid or high clouds. |
| Tuesday afternoon and night: |
Mostly cloudy with chance of light rain or snow. |
Extended Forecast for Sunday through Tuesday ("Snow Levels")
Olympics and Cascades--Mt Baker (N) to Mt Hood (S)
| Time | Olympics |
North Cascades | Central Cascades | South Cascades |
| FREEZING LEVELS | ||||
| Sunday and Monday: |
9000 |
9000 | 9000 | 9000 |
| SNOW LEVELS | ||||
| Tuesday morning: |
7000 | 7000 | 7000 | 7000 |
| Later Tuesday: |
5000 |
5000 | 5000 | 5000 |
Except near the surface in the lower Cascade passes and east slopes especially night and morning hours.
NWAC weather data and forecasts are also available by calling 206-526-6677 for Washington, 503-808-2400 for the Mt Hood area, or by visiting our Web site at www.nwac.us.
Ferber/Northwest Weather and Avalanche Center Seattle Washington