Issued: 2:06 PM PST Monday, December 30, 2019
by Dennis D'Amico

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

Weather Synopsis for Monday night through Tuesday

A big change in the weather pattern is on our doorstep as weak upper level ridging flattens today and tonight and allows a low pressure system in the Gulf of Alaska and a strong jet stream to begin driving Pacific frontal systems through our region over the next several days. 

This switch to a progressive weather pattern begins with warm frontal moisture arriving for the Olympics and north Cascades tonight and spreading south during the day on Tuesday. Warm air will be advected into the region, resulting in rising snow levels. The devil is in the details of course, and cool easterly flow through the Passes will keep precipitation frozen in the morning before snow levels skyrocket in the afternoon, earlier for White Pass, later in the day for Stevens Pass. A period of freezing rain is possible for White and Snoqualmie Passes tomorrow morning before the switch over. For the north Cascades and along the east slopes of the Cascades lower snow levels will hold through the daylight hours on Tuesday with a much slower warming trend anticipated. West winds at crest-level will ramp up quickly in the afternoon for all areas. Expect stormy conditions by the end of the day Tuesday. 

The occluded front will pass through the Cascades Tuesday evening for continued moderate to heavy precipitation and a trailing shortwave should invigorate post-frontal showers for the south Washington Cascades and Mt. Hood area later Tuesday night. Snow levels should peak for the west slopes early Tuesday evening and begin to slowly decrease overnight. Warmer air will finally work its way over the to east side of the Cascades Tuesday night, scouring out the remaining cold air. Continued westerly flow should continue orographic showers through Wednesday with snow levels continuing their downward trend. 

Weather Forecast

Hurricane Ridge
Monday Night Cloudy with periods of light rain and snow.
Mt. Baker
Monday Night Cloudy with light rain and snow.
Washington Pass and Leavenworth
Monday Night Cloudy with light rain and snow developing after midnight.
Stevens and Snoqualmie Pass
Monday Night Cloudy with light rain and snow developing after midnight. Light east wind in the Passes becoming moderate overnight.
Mt. Rainier, Crystal and White Pass
Monday Night Cloudy with light rain and snow developing late.
Mt. Hood
Monday Night Mostly cloudy in the evening becoming cloudy with light rain and snow developing late.

Snow/Freezing Level (ft)

Hurricane Ridge Mt. Baker Washington Pass Leavenworth Stevens Pass Snoqualmie Pass Mt. Rainier, Crystal & White Pass Mt. Hood
Monday Evening Snow Level 4500' 3500' 2000' 2000' 3000' 3500' 3500' 5500'
Monday Night Snow Level * 5000' 3500' 2000' 2000' 3000' 3000' 3500' 6000'
Tuesday Morning Snow Level * 6500' 3500' 2000' 2000' 3000' 3000' 4000' 5500'
Tuesday Afternoon Snow Level * 7000' 4500' 3500' 4500' 5000' 6500' 8000' 7000'
Tuesday Evening Snow Level 7000' 6000' 5500' 6500' 6500' 7000' 6500' 7500'
Tuesday Night Snow Level 5000' 5500' 5000' 5500' 5500' 5500' 5500' 6000'
Wednesday Morning Snow Level 4000' 4000' 4000' 4500' 4000' 4500' 4500' 5000'
Hurricane Ridge Elevation
Monday Evening Snow Level
4500'
Monday Night Snow Level
5000'
(Easterly Flow *)
Tuesday Morning Snow Level
6500'
(Easterly Flow *)
Tuesday Afternoon Snow Level
7000'
(Easterly Flow *)
Tuesday Evening Snow Level
7000'
Tuesday Night Snow Level
5000'
Wednesday Morning Snow Level
4000'
Wednesday Afternoon Snow Level
3500'
Mt. Baker Elevation
Monday Evening Snow Level
3500'
Monday Night Snow Level
3500'
(Easterly Flow *)
Tuesday Morning Snow Level
3500'
(Easterly Flow *)
Tuesday Afternoon Snow Level
4500'
(Easterly Flow *)
Tuesday Evening Snow Level
6000'
Tuesday Night Snow Level
5500'
Wednesday Morning Snow Level
4000'
Wednesday Afternoon Snow Level
3500'
Washington Pass Elevation
Monday Evening Snow Level
2000'
Monday Night Snow Level
2000'
(Easterly Flow *)
Tuesday Morning Snow Level
2000'
(Easterly Flow *)
Tuesday Afternoon Snow Level
3500'
(Easterly Flow *)
Tuesday Evening Snow Level
5500'
Tuesday Night Snow Level
5000'
Wednesday Morning Snow Level
4000'
Wednesday Afternoon Snow Level
3500'
Leavenworth Elevation
Monday Evening Snow Level
2000'
Monday Night Snow Level
2000'
(Easterly Flow *)
Tuesday Morning Snow Level
2000'
(Easterly Flow *)
Tuesday Afternoon Snow Level
4500'
(Easterly Flow *)
Tuesday Evening Snow Level
6500'
Tuesday Night Snow Level
5500'
Wednesday Morning Snow Level
4500'
Wednesday Afternoon Snow Level
4000'
Stevens Pass Elevation
Monday Evening Snow Level
3000'
Monday Night Snow Level
3000'
(Easterly Flow *)
Tuesday Morning Snow Level
3000'
(Easterly Flow *)
Tuesday Afternoon Snow Level
5000'
(Easterly Flow *)
Tuesday Evening Snow Level
6500'
Tuesday Night Snow Level
5500'
Wednesday Morning Snow Level
4000'
Wednesday Afternoon Snow Level
3500'
Snoqualmie Pass Elevation
Monday Evening Snow Level
3500'
Monday Night Snow Level
3000'
(Easterly Flow *)
Tuesday Morning Snow Level
3000'
(Easterly Flow *)
Tuesday Afternoon Snow Level
6500'
(Easterly Flow *)
Tuesday Evening Snow Level
7000'
Tuesday Night Snow Level
5500'
Wednesday Morning Snow Level
4500'
Wednesday Afternoon Snow Level
4000'
Mt. Rainier & Crystal Elevation
Monday Evening Snow Level
3500'
Monday Night Snow Level
3500'
(Easterly Flow *)
Tuesday Morning Snow Level
4000'
(Easterly Flow *)
Tuesday Afternoon Snow Level
8000'
(Easterly Flow *)
Tuesday Evening Snow Level
6500'
Tuesday Night Snow Level
5500'
Wednesday Morning Snow Level
4500'
Wednesday Afternoon Snow Level
4000'
Mt. Hood Elevation
Monday Evening Snow Level
5500'
Monday Night Snow Level
6000'
(Easterly Flow *)
Tuesday Morning Snow Level
5500'
(Easterly Flow *)
Tuesday Afternoon Snow Level
7000'
(Easterly Flow *)
Tuesday Evening Snow Level
7500'
Tuesday Night Snow Level
6000'
Wednesday Morning Snow Level
5000'
Wednesday Afternoon Snow Level
4000'

* 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

Monday Night Tuesday Tuesday Night Tuesday
4 pm - 4 am 4 am - 4 pm 4 pm - 4 am 4 am - 4 pm
Hurricane Ridge LT 0.25 0.75 0.75 0.25
Mt Baker Ski Area LT 0.25 1.00 - 1.50 1.00 - 1.50 0.50 - 0.75
Washington Pass LT 0.10 0.50 0.50 - 0.75 0.25
Leavenworth 0 0.25 0.50 - 0.75 0.25
Stevens Pass LT 0.25 0.75 -1.00 1.00 - 1.50 0.75 -1.00
Snoqualmie Pass LT 0.25 1.00 1.00 - 1.50 0.75 -1.00
Mission Ridge 0 LT 0.25 0.25 - 0.50 LT 0.10
Crystal Mt LT 0.10 0.50 1.00 - 1.50 0.25 - 0.50
Paradise LT 0.10 1.00 - 1.50 1.50 0.75 -1.00
White Pass LT 0.10 0.75 1.50 0.50
Mt Hood Meadows 0 0.25 - 0.50 2.00 0.75
0 0.25 - 0.50 2.00 0.75
Hurricane Ridge Precipitation Forecast
Monday Night LT 0.25
Tuesday 0.75
Tuesday Night 0.75
Tuesday 0.25
Mt Baker Ski Area Precipitation Forecast
Monday Night LT 0.25
Tuesday 1.00 - 1.50
Tuesday Night 1.00 - 1.50
Tuesday 0.50 - 0.75
Washington Pass Precipitation Forecast
Monday Night LT 0.10
Tuesday 0.50
Tuesday Night 0.50 - 0.75
Tuesday 0.25
Leavenworth Precipitation Forecast
Monday Night 0
Tuesday 0.25
Tuesday Night 0.50 - 0.75
Tuesday 0.25
Stevens Pass Precipitation Forecast
Monday Night LT 0.25
Tuesday 0.75 -1.00
Tuesday Night 1.00 - 1.50
Tuesday 0.75 -1.00
Snoqualmie Pass Precipitation Forecast
Monday Night LT 0.25
Tuesday 1.00
Tuesday Night 1.00 - 1.50
Tuesday 0.75 -1.00
Mission Ridge Precipitation Forecast
Monday Night 0
Tuesday LT 0.25
Tuesday Night 0.25 - 0.50
Tuesday LT 0.10
Crystal Mt Precipitation Forecast
Monday Night LT 0.10
Tuesday 0.50
Tuesday Night 1.00 - 1.50
Tuesday 0.25 - 0.50
Paradise Precipitation Forecast
Monday Night LT 0.10
Tuesday 1.00 - 1.50
Tuesday Night 1.50
Tuesday 0.75 -1.00
White Pass Precipitation Forecast
Monday Night LT 0.10
Tuesday 0.75
Tuesday Night 1.50
Tuesday 0.50
Mt Hood Meadows Precipitation Forecast
Monday Night 0
Tuesday 0.25 - 0.50
Tuesday Night 2.00
Tuesday 0.75
Timberline Precipitation Forecast
Monday Night 0
Tuesday 0.25 - 0.50
Tuesday Night 2.00
Tuesday 0.75

Free Winds at 5000' (mph)

Hurricane Ridge Mt. Baker Stevens to Snoqualmie Pass Mt. Rainier Mt. Hood
Monday Evening SW 5 - 15 SW 10 - 20 W 10 - 20 W 10 - 20 WNW 15 - 25
Monday Night SW 10 - 20 S 10 - 20 W 10 - 20 W 10 - 20 WNW 20 - 30
Tuesday Morning SW 15 - 25 S 15 - 25 SW 15 - 25 SW 15 - 25 W 20 - 30
Hurricane Ridge Elevation
Monday Evening SW 5 - 15
Monday Night SW 10 - 20
Tuesday Morning SW 15 - 25
Tuesday Afternoon WSW 25 - 35
Mt. Baker Elevation
Monday Evening SW 10 - 20
Monday Night S 10 - 20
Tuesday Morning S 15 - 25
Tuesday Afternoon S 30 - 40
Stevens and Snoqualmie Pass Elevation
Monday Evening W 10 - 20
Monday Night W 10 - 20
Tuesday Morning SW 15 - 25
Tuesday Afternoon SW 25 - 35
Mt. Rainier Elevation
Monday Evening W 10 - 20
Monday Night W 10 - 20
Tuesday Morning SW 15 - 25
Tuesday Afternoon SW 25 - 35
Mt. Hood Elevation
Monday Evening WNW 15 - 25
Monday Night WNW 20 - 30
Tuesday Morning W 20 - 30
Tuesday Afternoon W 25 - 35
Hurricane Ridge Direction - Speed
Monday Evening SW 5 - 15
Monday Night SW 10 - 20
Tuesday Morning SW 15 - 25
Tuesday Afternoon WSW 25 - 35
Mt. Baker Direction - Speed
Monday Evening SW 10 - 20
Monday Night S 10 - 20
Tuesday Morning S 15 - 25
Tuesday Afternoon S 30 - 40
Stevens and Snoqualmie Pass Direction - Speed
Monday Evening W 10 - 20
Monday Night W 10 - 20
Tuesday Morning SW 15 - 25
Tuesday Afternoon SW 25 - 35
Mt. Rainier Direction - Speed
Monday Evening W 10 - 20
Monday Night W 10 - 20
Tuesday Morning SW 15 - 25
Tuesday Afternoon SW 25 - 35
Mt. Hood Direction - Speed
Monday Evening WNW 15 - 25
Monday Night WNW 20 - 30
Tuesday Morning W 20 - 30
Tuesday Afternoon W 25 - 35

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
Monday Evening W 20 - 30 W 20 - 30 NW 25 - 35 NW 25 - 35 NW 25 - 35
Monday Night W 20 - 30 W 20 - 30 NW 25 - 35 NW 25 - 35 NW 30 - 40
Tuesday Morning WSW 25 - 35 WSW 20 - 30 W 30 - 40 W 30 - 40 NW 35 - 45
Mt. Baker Direction - Speed
Monday Evening W 20 - 30
Monday Night W 20 - 30
Tuesday Morning WSW 25 - 35
Tuesday Afternoon W 40 - 60
Washington Pass Direction - Speed
Monday Evening W 20 - 30
Monday Night W 20 - 30
Tuesday Morning WSW 20 - 30
Tuesday Afternoon W 40 - 50
Stevens and Snoqualmie Pass Direction - Speed
Monday Evening NW 25 - 35
Monday Night NW 25 - 35
Tuesday Morning W 30 - 40
Tuesday Afternoon W 40 - 60
Mt. Rainier Direction - Speed
Monday Evening NW 25 - 35
Monday Night NW 25 - 35
Tuesday Morning W 30 - 40
Tuesday Afternoon W 40 - 60
Mt. Hood Direction - Speed
Monday Evening NW 25 - 35
Monday Night NW 30 - 40
Tuesday Morning NW 35 - 45
Tuesday Afternoon WNW 40 - 60

Extended Weather Synopsis for Tuesday night through Tuesday

Showers will decrease but not end Wednesday night as snow levels plummet further. Another warm front now looks likely to pass through the area Thursday and Thursday night for another round of moderate precipitation and slowly rising snow levels. On Friday, our region is in the warm sector of the storm as the warm front lifts north of the area and the trailing cold front positioned offshore. Precipitation, if any, should be light but snow levels will be on the mild side. 

Extended Snow/Freezing Levels

Mt. Baker Snoqualmie Pass Mt. Hood Easterly Flow *
Wednesday Night Snow Level 1000' - 2000' 1500' - 2500' 2000' - 3000'
Thursday Snow Level 1500' - 2500' 2000' - 3000' 4000' - 5000'
Thursday Night Snow Level 3000' - 4500' 3500' - 5000' 4500' - 6000' *
Mt. Baker Elevation
Wednesday Night Snow Level
1000' - 2000'
Thursday Snow Level
1500' - 2500'
Thursday Night Snow Level
3000' - 4500'
(Easterly Flow *)
Friday Snow Level
5000' - 6000'
(Easterly Flow *)
Snoqualmie Pass Elevation
Wednesday Night Snow Level
1500' - 2500'
Thursday Snow Level
2000' - 3000'
Thursday Night Snow Level
3500' - 5000'
(Easterly Flow *)
Friday Snow Level
5500' - 6500'
(Easterly Flow *)
Mt. Hood Elevation
Wednesday Night Snow Level
2000' - 3000'
Thursday Snow Level
4000' - 5000'
Thursday Night Snow Level
4500' - 6000'
(Easterly Flow *)
Friday Snow Level
5500' - 6500'
(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.

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

Previous forecast from Dec 30, 2019

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