Issued: 1:50 PM PST Saturday, February 10, 2018
by Robert Hahn

Jump to: Weather Forecast I Snow/Freezing Level I Precipitation I Free Winds 5k I Free Winds 9k I Extended Weather

Weather Synopsis for Saturday & Saturday

A strong upper ridge of high pressure remains will remain far enough offshore that the Pacific Northwest will experience low freezing/snow levels through the weekend. 

Although temperatures at most NWAC stations were in the 10's and 20's, the influence of the offshore high pressure ridge has enabled temperatures to warm up substantially, particularly west of the Cascade Crest. Hurricane Ridge saw temperatures rise 20F over the course of 5 hours on Saturday morning. The flow in most locations has shifted  to westerly as a moisture-starved upper-level and surface closed low will approach from the northwest. The approaching low will bring a another shot of cooler air into the Pacific Northwest, but without a significant frontal feature. Westerly winds will increase into the moderate range at crest level over the north and central Cascades as the low approaches.

This fast-moving low will approach the near-shore waters late Saturday night and by Sunday morning it will make landfall on the central Oregon coast.

The compact low will bring a chance of some very light snow showers to the Olympics, central and south Cascades, and Mt. Hood, but it doesn't look like much moisture will make it onshore, so mostly expect clouds and cooling from this system.

Sunday night, expect clearing skies and with colder temperatures due to radiational cooling along with colder air moving in from the interior on weak NE flow as a high pressure builds offshore once again. Snow levels will fall to very close to sea level.

Weather Forecast

Olympics
Saturday High clouds.
Saturday Night Clouds with a chance of light snow showers by morning.
Sunday Chance of light snow showers, mainly as the flow turns northerly in the early afternoon hours.
Washington Cascades near and west of the Crest including Stevens, Snoqualmie and White Passes
Saturday High clouds moving in.
Saturday Night High clouds and fair. Some fog in the lowlands.
Sunday A mix of clouds and sun with some light snow showers.
East Slopes of the Washington Cascades
Saturday Clear and fair.
Saturday Night Some high clouds and fair. Fog and low clouds developing in some lowland locations or deep valleys.
Sunday Partly cloudy with a chance of light snow showers.
Mt. Hood
Saturday High clouds and fair.
Saturday Night High clouds and fair. Some very low clouds or fog.
Sunday Increasing clouds with light snow developing during the morning hours. and becoming light snow showers during the afternoon.

Snow/Freezing Level (ft)

Hurricane Ridge Mt. Baker Washington Pass Leavenworth Stevens Pass Snoqualmie Pass Mt. Rainier, Crystal & White Pass Mt. Hood
Saturday Afternoon Freezing Level 3000' 3000' 3500' ' ' 4000' ' 4500'
Saturday Night Freezing Level 2500' 2500' 2500' ' ' 3500' ' 6500'
Sunday Morning Snow Level 1500' 1000' 1000' ' ' 2000' ' 2500'
Sunday Afternoon Snow Level 1500' 1500' 1500' ' ' 2000' ' 2500'
Hurricane Ridge Elevation
Saturday Afternoon Freezing Level
3000'
Saturday Night Freezing Level
2500'
Sunday Morning Snow Level
1500'
Sunday Afternoon Snow Level
1500'
Sunday Night Snow Level
0'
(Easterly Flow *)
Mt. Baker Elevation
Saturday Afternoon Freezing Level
3000'
Saturday Night Freezing Level
2500'
Sunday Morning Snow Level
1000'
Sunday Afternoon Snow Level
1500'
Sunday Night Snow Level
0'
(Easterly Flow *)
Washington Pass Elevation
Saturday Afternoon Freezing Level
3500'
Saturday Night Freezing Level
2500'
Sunday Morning Snow Level
1000'
Sunday Afternoon Snow Level
1500'
Sunday Night Snow Level
0'
(Easterly Flow *)
Leavenworth Elevation
Saturday Afternoon Freezing Level
'
Saturday Night Freezing Level
'
Sunday Morning Snow Level
'
Sunday Afternoon Snow Level
'
Sunday Night Snow Level
'
(Easterly Flow *)
Stevens Pass Elevation
Saturday Afternoon Freezing Level
'
Saturday Night Freezing Level
'
Sunday Morning Snow Level
'
Sunday Afternoon Snow Level
'
Sunday Night Snow Level
'
(Easterly Flow *)
Snoqualmie Pass Elevation
Saturday Afternoon Freezing Level
4000'
Saturday Night Freezing Level
3500'
Sunday Morning Snow Level
2000'
Sunday Afternoon Snow Level
2000'
Sunday Night Snow Level
1000'
(Easterly Flow *)
Mt. Rainier & Crystal Elevation
Saturday Afternoon Freezing Level
'
Saturday Night Freezing Level
'
Sunday Morning Snow Level
'
Sunday Afternoon Snow Level
'
Sunday Night Snow Level
'
(Easterly Flow *)
Mt. Hood Elevation
Saturday Afternoon Freezing Level
4500'
Saturday Night Freezing Level
6500'
Sunday Morning Snow Level
2500'
Sunday Afternoon Snow Level
2500'
Sunday Night Snow Level
1000'
(Easterly Flow *)

* Easterly flow in the Cascade Passes can cause locally lower Snow or Freezing levels than areas further west.
Freezing Level is when no precipitation is forecast.

Precipitation Forecast

Saturday Saturday
Hurricane Ridge LT 0.10 LT 0.10
Mt Baker Ski Area LT 0.10 LT 0.10
Washington Pass LT 0.10 LT 0.10
Stevens Pass LT 0.10 LT 0.10
Snoqualmie Pass LT 0.10 LT 0.10
Mission Ridge LT 0.10 LT 0.10
Crystal Mt LT 0.10 LT 0.10
Paradise LT 0.10 LT 0.10
White Pass LT 0.10 LT 0.10
Mt Hood Meadows LT 0.10 LT 0.10
LT 0.10 LT 0.10

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Saturday Afternoon W 10 - 20 WSW 5 - 15 W 5 - 15 --- - VAR 0 - 10
Saturday Night W 10 - 20 SW 5 - 15 W 10 - 20 --- - W 15 - 25
Sunday Morning N 0 - 10 W 5 - 15 W 5 - 15 --- - W 10 - 20
Sunday Afternoon N 5 - 15 N 5 - 15 NNW 5 - 15 --- - WNW 5 - 15
Hurricane Ridge Elevation
Saturday Afternoon W 10 - 20
Saturday Night W 10 - 20
Sunday Morning N 0 - 10
Sunday Afternoon N 5 - 15
Sunday Night NE 10 - 20
Mt. Baker Elevation
Saturday Afternoon WSW 5 - 15
Saturday Night SW 5 - 15
Sunday Morning W 5 - 15
Sunday Afternoon N 5 - 15
Sunday Night NNE 10 - 20
Stevens and Snoqualmie Pass Elevation
Saturday Afternoon W 5 - 15
Saturday Night W 10 - 20
Sunday Morning W 5 - 15
Sunday Afternoon NNW 5 - 15
Sunday Night VAR 0 - 10
Mt. Rainier Elevation
Saturday Afternoon --- -
Saturday Night --- -
Sunday Morning --- -
Sunday Afternoon --- -
Sunday Night --- -
Mt. Hood Elevation
Saturday Afternoon VAR 0 - 10
Saturday Night W 15 - 25
Sunday Morning W 10 - 20
Sunday Afternoon WNW 5 - 15
Sunday Night NE 10 - 20
Hurricane Ridge Direction - Speed
Saturday Afternoon W 10 - 20
Saturday Night W 10 - 20
Sunday Morning N 0 - 10
Sunday Afternoon N 5 - 15
Sunday Night NE 10 - 20
Mt. Baker Direction - Speed
Saturday Afternoon WSW 5 - 15
Saturday Night SW 5 - 15
Sunday Morning W 5 - 15
Sunday Afternoon N 5 - 15
Sunday Night NNE 10 - 20
Stevens and Snoqualmie Pass Direction - Speed
Saturday Afternoon W 5 - 15
Saturday Night W 10 - 20
Sunday Morning W 5 - 15
Sunday Afternoon NNW 5 - 15
Sunday Night VAR 0 - 10
Mt. Rainier Direction - Speed
Saturday Afternoon --- -
Saturday Night --- -
Sunday Morning --- -
Sunday Afternoon --- -
Sunday Night --- -
Mt. Hood Direction - Speed
Saturday Afternoon VAR 0 - 10
Saturday Night W 15 - 25
Sunday Morning W 10 - 20
Sunday Afternoon WNW 5 - 15
Sunday Night NE 10 - 20

Directions above indicate the direction the wind blows from on the 16-point cardinal scale. These winds 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' (mph)

Mt. Baker Washington Pass Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Saturday Afternoon W 25 - 35 W 20 - 30 W 25 - 35 --- - NNW 10 - 20
Saturday Night W 20 - 30 W 20 - 30 W 30 - 40 --- - W 30 - 40
Sunday Morning NNE 10 - 20 NNE 5 - 15 WNW 15 - 25 --- - W 30 - 40
Sunday Afternoon N 15 - 25 N 20 - 30 ENE 10 - 20 --- - NW 20 - 30
Mt. Baker Direction - Speed
Saturday Afternoon W 25 - 35
Saturday Night W 20 - 30
Sunday Morning NNE 10 - 20
Sunday Afternoon N 15 - 25
Sunday Night NE 25 - 35
Washington Pass Direction - Speed
Saturday Afternoon W 20 - 30
Saturday Night W 20 - 30
Sunday Morning NNE 5 - 15
Sunday Afternoon N 20 - 30
Sunday Night NNE 20 - 30
Stevens and Snoqualmie Pass Direction - Speed
Saturday Afternoon W 25 - 35
Saturday Night W 30 - 40
Sunday Morning WNW 15 - 25
Sunday Afternoon ENE 10 - 20
Sunday Night N 15 - 25
Mt. Rainier Direction - Speed
Saturday Afternoon --- -
Saturday Night --- -
Sunday Morning --- -
Sunday Afternoon --- -
Sunday Night --- -
Mt. Hood Direction - Speed
Saturday Afternoon NNW 10 - 20
Saturday Night W 30 - 40
Sunday Morning W 30 - 40
Sunday Afternoon NW 20 - 30
Sunday Night NNE 15 - 25

Extended Weather Synopsis for Saturday night through Saturday

A northeasterly flow will keep cool air in place on Monday as fair weather prevails. Monday night the flow aloft  will switch to northerly as an E-W oriented high pressure bulges into the Pacific Northwest with a deeper trough to the north and the departed closed low to the south over California. Light to moderate easterly flow can be expected at the passes Monday and Monday night. 

Tuesday will feature high pressure with light winds and warming for many locations as an approaching system from the N-NW shifts the flow to allow warmer air from the Pacific high to come onshore. Expect more spring-like conditions on Tuesday.

Tuesday night will see the onset of a broad trough and a weakening storm system on N-NW flow. Temperatures will cool significantly as the storm approaches and arrives with low snow levels on Wednesday. Snow showers can be expected in the mountains Tuesday night and Wednesday on a cool N-NW flow.

Extended Weather

Olympics, Washington Cascades and Mt. Hood Area
Monday Cold on the east slopes with moderately east flow through the passes. Otherwise, winds should be light and variable with sun and some low clouds east of the Cascade crest. Monday night will be clear and fair. Tuesday Tuesday will be warm and spring-like with light and variable winds. Clouds and some light rain or snow will arrive along with cooling temperatures. Wednesday Decreasing light snow showers are possible on Wednesday with below-normal temperatures.

Extended Snow/Freezing Levels

Mt. Baker Snoqualmie Pass Mt. Hood Easterly Flow *
Monday Freezing Level 500' - 2500' 1000' - 3000' 500' - 2500' *
Monday Night Freezing Level 1500' - 2500' 2500' - 3500' 3000' - 5000' *
Tuesday Freezing Level 2000' - 3000' 4000' - 5000' 7000' - 9000'
Tuesday Night Snow Level 1000' - 2000' 2000' - 3000' 3000' - 5000'
Mt. Baker Elevation
Monday Freezing Level
500' - 2500'
(Easterly Flow *)
Monday Night Freezing Level
1500' - 2500'
(Easterly Flow *)
Tuesday Freezing Level
2000' - 3000'
Tuesday Night Snow Level
1000' - 2000'
Wednesday Snow Level
1500' - 2500'
Snoqualmie Pass Elevation
Monday Freezing Level
1000' - 3000'
(Easterly Flow *)
Monday Night Freezing Level
2500' - 3500'
(Easterly Flow *)
Tuesday Freezing Level
4000' - 5000'
Tuesday Night Snow Level
2000' - 3000'
Wednesday Snow Level
500' - 1500'
Mt. Hood Elevation
Monday Freezing Level
500' - 2500'
(Easterly Flow *)
Monday Night Freezing Level
3000' - 5000'
(Easterly Flow *)
Tuesday Freezing Level
7000' - 9000'
Tuesday Night Snow Level
3000' - 5000'
Wednesday Snow Level
2000' - 3000'

* Easterly flow in the Cascade Passes can cause locally lower Snow or Freezing levels than areas further west.
Freezing Level is when no precipitation is forecast.

Jump to: Weather Forecast I Snow/Freezing Level I Precipitation I Free Winds 5k I Free Winds 9k I Extended Weather

Previous forecast from Feb 10, 2018

The NWAC program is administered by the USDA-Forest Service and operates from 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.