MOUNTAIN WEATHER FORECAST

Stevens Pass Mountain Weather Forecast

Day and Time: Friday 0800

Current Observations:

24hr Precipitation:  Light snow showers with 1” of fresh on the ground.  

Pass temperature: 31

Pass level winds: 0-10 W

Barometer: holding @ 1003mb’s 

Sky: Overcast

Radar: Light scattered snow showers along the western slopes with a small convergence zone formed to the north of Stevens Pass.

The Forecast:  Snow showers today and tomorrow with cooler temperatures moving in.  A cold, dry weather pattern will develop on Sunday.

Long Range:  The cold and dry weather will likely last through at least Friday. Early morning temperatures could dip down to the low teens or even single digits Monday through Thursday.  Watch for a low elevation cloud layer to develop east of the mountains.

  

The Science:  A low pressure cell, currently centered over the Vancouver Island region, will track SSE today.  Unstable westerly flow will spin bands of moisture through the mountains for the next 24hrs as this system moves through. There isn’t a lot of energy associated with this system, but hopefully we can squeeze a few inches of snow out of it before it heads into intermountain west.  

On Sunday, the strengthening high pressure ridge forming out along the coast will allow cold stable air to flow in from the northern interior.  A strong offshore/east flow pressure gradient will form as the cold temperatures settle into the basin.  The ingredients to form an inversion layer east of the mountains and clear conditions at higher elevations will be in place.   

Values from 4am today through

 4am tomorrow.

Precipitation: Today 24hr water:.25   snow: 1-2 Tomorrow’s 24hr water:.25  snow: 1-3 Trend and Timing: Light passing snow showers will continue through tomorrow afternoon.

Temperature: Low:24     High:32 Freezing level: 4000’ – 2500’ Trend and Timing:    Freezing levels will fall tonight with surface temperatures dropping into the low 20s’.

Winds Base: 0-5 W shifting E Ridge Top: 5-10 WSW shifting E Trend and Timing: Westerly flow with shift easterly over the next 12- 24hrs.

MOUNTAIN WEATHER FORECAST

Stevens Pass Mountain Weather Forecast

Day and Time: Thursday 0700

The Snapshot: Unfortunately, the snow we hoped for last night slid right on by and headed to Oregon.

Mostly dry today with light passing snow showers expected tomorrow.  The weekend will be dry with colder temperatures moving in.  We could see the lowest temperatures of this winter season early Sunday morning.

Current Observations:

Precipitation: .01” of moisture showing up on the telemetry.   

Pass temperature: 32

Winds: 5-10 E

Barometer: fallen to 1003mb’s  

Sky:  overcast

Radar:  The State is mostly dry with all of the moisture now in Oregon.

The Forecast: Cloudy today with temperatures near freezing.  Light passing snow showers will be possible tomorrow with dry and cold weather developing over the weekend.     

Long Range: The dry and cold weather pattern will likely continue through most of next week.

  

The Science: Most of the energy has shifted to the SW of Washington State. Isobars are slacking with some weak mid-level ridging developing.  A weak low pressure system will track down the PNW coastal waters over the next 24-36hrs.  Similar to yesterday, most of the moisture will remain west of the Cascade Crest as it moves south. 

Cold Temperatures:  An elongated high pressure ridge stretching in the Gulf of Alaska will be the mechanism to allow cold northerly air to flow into eastern Washington over the weekend.  Winds blowing in from the interior north will carry a cold dry air mass into the PNW starting on Saturday.  Early morning temperatures could drop into the middle teens. In the long term (Sunday – Thursday) the atmosphere will become stable and thus, cold and clear.  

Values from 4am today through

 4am tomorrow.

Precipitation: Today 24hr water: .10  snow: trace Tomorrow’s 24hr water: <.25   snow: 0-2 Trend and Timing: Occasional light passing snow showers will persist through early Saturday morning.

Temperature: Low:28     High:34 Freezing level: +- 4000’ Trend and Timing:    Freezing levels will hold at 4000’ through tomorrow with colder air moving in on Saturday.

Winds Base: 0-5 E Ridge Top: 5-10 E Trend and Timing: East flow will strengthen today.

MOUNTAIN WEATHER FORECAST

Stevens Pass Mountain Weather Forecast

Day and Time: Wednesday 0800

The Snapshot:  Light to moderate snow showers tonight.  A short dry period is expected tomorrow with more light snow on Friday/Saturday.  Snow totals by Saturday could be in the neighborhood of = 5-10”.  Think snow.

Current Observations: It was nice of those left over convergence showers to leave a  few inches of snow on the ground.  +- 4”.  Nice.

Water equivalent for that little rain event =  3-3.5” of water.  Mnt Baker received over 9” of rain.   

Precipitation: 24hr totals = 1.02” of water, 4” of snow

 Pass temperature:  33

Winds: 5-10 WSW

Barometer:  holding at 1007mbs

Sky: Overcast with patchy fog.

Radar:  Mixed snow and rain showers moving north along the western slopes

The Forecast:  Passing snow showers with slowly falling temperatures will be the weather pattern for the remainder of the week.

Long Range: Things will begin to dry out and cool down over the weekend with a dry and cold weather persisting into next week.  

  

The Science:  The westerly flow that filled in behind the cold front yesterday kept the atmosphere relatively unstable with plenty of moisture left over.  The flow aloft is SW to NE with the main moisture band moving along the western slopes, thus no convergence zone effect.  Stevens will hopefully squeeze few inches of snow out of these passing systems over the next few days.  

The upper level flow turns northerly with complex weak low pressure systems sliding south along coastal region.  This will be the source of any moisture that Stevens Pass may or may not get.   

Long Range modeling:  A strong high pressure ridge offshore will begin to stretch up into the Gulf of Alaska over the weekend.  This will likely create a blocking effect as it drifts inland early next week. 

Values from 4am today through

 4am tomorrow.

Precipitation: Today 24hr water: .5  snow: 4-6 Tomorrow’s 24hr water: .25  snow: 2-4 Trend and Timing: A short period of snow starting after 7pm tonight with drying starting after 4am.

Temperature: Low: 30    High:34 Freezing level: 5000’ – 4000’ Trend and Timing:    Freezing levels will slowly fall today and stabilize around 4000’ tomorrow.

Winds Base: 0-5 WSW shifting E Ridge Top: 5-10 SSW shifting E Trend and Timing: The winds will shift easterly over the next 24hrs.

MOUNTAIN WEATHER FORECAST

Stevens Pass Mountain Weather Forecast

Day and Time: Tuesday 0700

The Snapshot:  The moisture will begin to diminish later today with temperatures slowly falling.  Mostly dry and cooler tomorrow with a chance of light snow early Thursday morning and then again Friday.

Current Observations:

Precipitation: 1.92” of water fell over the past 24hr with 0” of snow showing up on the Schmidt Haus telemetry.  The upper mountain received around 2” of very wet snow.    

Pass temperature: 32

Pass level winds: 5-10 E

Barometer: dropped to 1005mbs

Sky: overcast

Radar:  The radar shows light scattered showers over the north central mountains with a band of heavy moisture moving through the South Sound region.

The Forecast:  Things will begin to dry out later today with tonight and tomorrow being mostly dry with some partial clearing.  The winds shift westerly today with freezing levels slowly dropping overnight.  There will be and inch or two of snow likely Thursday morning with some light snow on Friday as well.

Long Range: Cooler with little to no precipitation is expected over the weekend.  Next week will start out clear, cold and dry.   

  

The Science:  The Cascades are currently between fronts with the warm front heading into the Canadian mountains and the following cold front just entering the Olympic Range.  The cold front is likely to occlude as it mixes with the warm inland surface temperatures.  The barometer should be at its lowest point this morning and begin to rise later today. Westerly flow with cooler upper air will begin to fill in this afternoon as well.

The jet stream forecast models have the storm track shifting to the south of Washington State of the next 36-48hrs.   Colder offshore flow develops over the weekend with dry and stable weather leading into the first full week of December.   

Values from 4am today through

 4am tomorrow.

Precipitation: Today 24hr water: .25-.5   snow: 0 Tomorrow’s 24hr water: .25  snow: 1-2 Trend and Timing: Rain showers will diminish this afternoon with tomorrow being mostly dry.

Temperature: Low: 32    High: 36 Freezing level: +- 6000’ -4500’ Trend and Timing:    Freezing levels will peak at or just above 6000’ this morning and then begin to slowly fall to +- 4500’ tonight.

Winds Base: 0-5 E shifting W Ridge Top: 5-15 W Trend and Timing: Winds shift westerly this morning with gusty ridge top winds possible.

MOUNTAIN WEATHER FORECAST

Stevens Pass Mountain Weather Forecast

Day and Time:  Monday 0630

The Snapshot:  Mixed snow and rain this morning will turn to all rain this afternoon. Diminishing rain showers tomorrow with cooler temperatures and snow at times for the remainder of the week.

Current Observations:

Precipitation: Light rain in the base area with mixed snow and rain on the upper mountain

Pass temperature: 30

Pass level winds: 0-5 E

Barometer: 1017mbs and falling 

Sky: Overcast

Radar:  The radar is lit up this morning with heavy rain and high winds throughout western Washington. Mixed snow and rain below 4500’ with snow in North Cascades

The Forecast:  The snow will switch to all rain today as the freezing level rises above 5000’.   The heaviest period of rain is expected tonight.  The rain tapers off tomorrow with snow showers expected on Wednesday.

Long Range: There is quite a bit of discrepancy in the models from Thursday – Sunday.  So as of now, there is a chance of a few inches of snow late Wednesday night/Thursday morning and then again on Friday.  The weekend appears to be dry and cold.  

The Science:  The leading warm front of the approaching triple point storm is just about to make land fall.  This storm has a large moisture stream stretching out to the SW.   Strong warm SW flow will overtake the weaker cold east flow over the next 12-24hrs.  The associated cold front is timing out to move through tomorrow morning.  Once the cold front passes east of the crest, the moisture stream will be cut off and the flow will shift westerly. Pressure gradients will also loosen tomorrow afternoon helping to break up the precipitation.  

A weak cut off low will swing through late Wednesday night producing a short period of moisture – possibly snow.  Another similar event will occur on Friday.

Values from 4am today through

 4am tomorrow.

Precipitation: Today 24hr water: .75-1  snow: 0-2 base, 2-4 upper mountain Tomorrow’s 24hr water: .5   snow: 0 Trend and Timing: Light to moderate snow/rain today turns moderate to heavy rain tonight. Rain tapers off after 7am tomorrow.

Temperature: Low: 32    High: 36 Freezing level: 4000’- 6000’ Trend and Timing:    Freezing levels will rise above 5000’ today. East flow at the surface will keep temperatures just above freezing through noon or so today.

Winds Base: 0-5 E Ridge Top: 5-10 SSE Trend and Timing: Pass level easterly winds weaken today and shift SW tomorrow.  Upper level winds will be generally southerly.

MOUNTAIN WEATHER FORECAST

Stevens Pass Mountain Weather Forecast

Day and Time: Sunday 0800

The Snapshot:  Dry today with increasing clouds.  The rain vs snow game begins early tomorrow morning.  Light rain on Tuesday with colder temperatures and snow showers expected for the rest of the week.

Current Observations:

Precipitation: 0 

Pass temperature: 26

Pass level winds: 5-10 E

Barometer: Holding at 1019mbs  

Sky: Clear

Radar: Rain along the coast with high clouds moving inland.

The Forecast:  Mixed rain and snow below 5000’ begins after midnight tonight.  The precipitation will intensify through the day.  The precipitation (likely rain) shifts to light showers on Tuesday.  

Long Range: Colder temperatures and intermittent snow showers will persist Wednesday through Friday. With some luck we could pick up an additional 4-6” of snow leading into the weeekend.   

  

The Science: The large low pressure system stirring in the Gulf of Alaska will slowly drift east over the next 12-14hrs.   A triple point frontal system is leading the charge.  The leading warm front is timing out to pass over the Cascade crest sometime after midnight tonight.  How the strong SW flow mixes with the cool east flow will determine whether the precipitation is white or clear.

Models have the east flow being overtaken on Tuesday with some upper level ridging breaking up the moisture stream.  The trailing cold front moves through late Tuesday with unstable cooler air filling in. 

Values from 4am today through

 4am tomorrow.

Precipitation: Today 24hr water: 1  snow: 2-4 Tomorrow’s 24hr water:.25-.5   snow: 0 Trend and Timing: Mixed rain and snow arrives after midnight tonight and intensifies through the day.

Temperature: Low: 30    High: 36 Freezing level: 3000’ – 4500’. Trend and Timing:    Freezing levels will rise to 4000’ today and then to 4500’ or even 5k tomorrow.

Winds Base: 0-10 E Ridge Top: 5-10 ESE Trend and Timing: East flow at the surface with SSE flow aloft will be the wind pattern through early Tuesday morning.

MOUNTAIN WEATHER FORECAST

Stevens Pass Mountain Weather Forecast

Day and Time:

The Snapshot:  The next 2 days will be dry with sun and moon appearances.  A snow changing to rain event is expected Monday and Tuesday with light snow showers for the remainder of the week.

Current Observations:

Precipitation: .65” of water produce 7” of snow over the last 24hrs.  

Pass temperature: 30

Pass level winds: light and out of the west

Barometer: 1003mb’s and rising

Sky: Morning patchy fog with broken clouds above

Radar: There are a few light rain showers up around the Bellingham area with the rest of the state dry.

The Forecast:  Today and tomorrow will be dry with clear periods.  Daytime temperatures will climb into the lower 30’s with early morning lows dipping into the mid to low 20’s.   The next system moves in on Monday morning with rising freezing levels. This will be a rain vs snow game at the start with rain likely on Tuesday.

Storm totals for Monday/ Tuesday are currently:

          4am Monday – 4am Tuesday = 1-1.5” of water, 3-5” of snow

          4am-Tuesday – 4am Wednesday = .75-1” of water,  1-2” of snow

Long Range: After the mixed snow and rain event, cooler air moves in with remnant snow showers expected for the remainder of the week.   Hopefully, we will pick up a few inches of additional snow by week’s end.   

  

The Science:  The rising barometer is the indicator of the high pressure building over the PNW.  Mid level clouds will be stubborn in the mountains with clear sky’s likely over the eastern basin.  Upper level clearing and east flow development will allow temperatures to drop into the mid 20’s tonight.  Westerly flow will be light and slowly shift SE to E through the day tomorrow. 

A large low pressure cell, developing in North Pacific, has its southern border stretching well into the California waters.  As this system drift east, it will bring in warm, moist southerly flow early Monday morning.  With the cool east flow intact, snow will be likely at the start.  The east flow will slowly be eroded as the warm air advection increase into Tuesday.  Long range models have freezing levels peaking near +-6000’ on Tuesday afternoon.   

Values from 4am today through

 4am tomorrow.

Precipitation: Today 24hr water: 0  snow: 0 Tomorrow’s 24hr water: .10  snow: trace Trend and Timing: Dry today with moisture moving in early Monday morning.

Temperature: Low: 24    High: 32 Freezing level: 4000’-3000’ Trend and Timing:    Freezing levels, with the aid of east flow, will fall to or even below 3000’ early tomorrow morning.

Winds Base: 0-5 W shifting E Ridge Top: 0-10 W shifting E Trend and Timing: East flow will develop and strengthen early tomorrow morning.