8am Start No ABS Monday Jan 1st, 2018!

Have a great New Years Eve.

Mountain Weather Forecast

Time and Day:  0730 Sunday

The Snapshot:   Mostly sunny today and tomorrow with easterly flow providing cool temperatures and pass level fog below the ridgetops.

Current Observations:  Temperatures are in the teens across the mountain, with fog in the base area and just a trace of new snow overnight. RH is at 93% and the barometer is steady over the past 12 hours.

The Science:   A high pressure ridge will amplify over the Pacific Northwest today, bringing rising freezing levels and mild weather. There is an offshore pressure gradient promoting easterly flow thru the passes, so Stevens will see the usual inversion scenario with intermittent fog in the base area.

The Long Range: Conditions remain similar for Tuesday and most of Wednesday, with models diverging on the exact track of a weak system Wednesday night.

24hr Precipitation ending at 4am: Today 24hr water:   0   Snow: 0 Tomorrow’s 24hr water:  0    Snow: 0 Trend and Timing: No precip expected for a few days.

24hr temperature ending at 4am:  Low:  15   High: 25 Free Air Freezing Level: 3,000 – 7,000’ Trend and Timing:    While upper air temps will be warmer above Pass level, Stevens should remain below the inversion line Sunday.

24hr Winds (mph) ending at 4am: Base: E 5-10 Ridge Top: E 10-15 Trend and Timing: Light easterly winds will continue all day Sunday. DV

8am Start No ABS Sunday December 31

Mountain Weather Forecast

Time and Day:  0630 Saturday

The Snapshot:   Light snow ending today, clear and warming Sunday.

Current Observations:  It’s currently snowing lightly with strong, gusty winds. Temperatures are 30 in the base area and mid 20’s on the upper mountain. There was a freezing rain event last night that has capped most of our new snow from yesterday. RH is 90% and the barometer is rising.

The Science:   A low pressure trough moved through yesterday afternoon/evening, dragging with it a warm upper level air-mass. Stevens Pass dodged the bullet for a while, but freezing rain accumulated between about 5pm and 8pm yesterday. In the trough’s wake this morning we have gusty (40-50mph) westerly winds with light snowfall. Strong west winds continuing for the next few hours should support orographic snow showers this morning, which will become light and end completely midday. High pressure builds in tonight and Sunday.

The Long Range: The high pressure ridge will build in strength and be in place for the start of the new year, with freezing levels around 6-8k’ Monday and Tuesday.

24hr Precipitation ending at 4am: Today 24hr water:  .25    Snow: 2-4” Tomorrow’s 24hr water:  0    Snow: 0 Trend and Timing: Light snow ending midday Saturday, dry Sunday.

24hr temperature ending at 4am:  Low: 25    High: 30 Snow level: 2000 Trend and Timing:    Temps will remain cool thru Sunday morning, and begin to warm Sunday afternoon.

24hr Winds (mph) ending at 4am: Base: W 20-30, then light East Ridge Top: W40-50 gusty, then WNW 10-15 Trend and Timing: The strong winds we are seeing this morning should diminish midday and become light and variable overnight.      DV

Call Off No AC Saturday 30th

6:15 ABS Yes Saturday December 30

MOUNTAIN WEATHER FORECAST

Time and Day: 1200 Friday

The Snapshot:   Heavy snow will continue through the night and begin to taper off tomorrow afternoon.   

The Science

Current Observations: Its 28 degrees and snowing, the ridge top winds are light and out of the south/west with east flow kicking in at Pass level. The radar is lit up with heavy precipitation falling in the mountains.   

The Forecast:  The warm front lifting up from the south today will keep mild temperatures and moderate to heavy precipitation falling in the mountains through the day.   A cold front swings through tonight with cool unstable westerly flow filling in behind the front.  Convergence conditions are likely to develop tonight keeping the snow machine cranking. A high pressure ridge will move into place tomorrow afternoon virtually shutting off the spigot.    

The Long Range:   The New Year will start out clear and dry.  

    

24hr Precipitation ending at 4 a.m: Today 24hr water: 1.5  snow: 14-17 Tomorrow’s 24hr water: .5 snow: 2-5 Trend and Timing: Snow will continue through the night and begin to taper off early tomorrow morning.

24hr temperature ending at 4 a.m:  Low: 26    High: 34 Freezing level: 4500’-3000’ Trend and Timing:    Freezing levels will hover near 4000’ today and then drop to 3000’ after midnight tonight.

24hr Winds (mph) ending at 4 a.m: Base: 0 -5 E shifting W Ridge Top: Trend and Timing: Winds will shift westerly tonight with the passing of the cold front.

jM

MOUNTAIN WEATHER FORECAST - Storm Update

No changes to this morning’s forecast.

There is a significant amount of moisture heading our way -  Freezing levels will be on the cusp trough noon tomorrow – with some luck we will not see much rain – but it will be wet heavy snow.  

Storm totals from 4am today through 4am Saturday are:  +-3” of water,  24-30” of snow  - barring the rain factor.    

Enjoy,  jM

Time and Day: 1100 Thursday

The Snapshot: Increasing snow today with temperatures near freezing. There will be a chance of short rain event tonight with heavy snow expected tomorrow.  The precipitation tapers off on Saturday with the remainder of the weekend trending dry.

The Science

Current Observations: It is snowing with 2” of new thus far.  The temperature is 32f, the RH is 100% and the barometer is 1017mb and falling.  The winds are westerly 5-10mph.  The radar has the approaching moisture just making landfall with light snow beginning to fall in the mountains.  

The Forecast: The snow will increase today as a frontal system (Triple Point) tracks east today.  This system will tap into a long fetch of moisture with heavy precipitation expected for the mountains through Saturday morning.  Snow or rain you ask?  Snow, mixed rain then snow…  

A weak warm front will lift up from the SW tonight pushing freezing levels up to around +-5000’.  The snow level will likely be lower than 5000’ with mixed snow and rain below the 4500’ gradually transitioning to rain through the lower elevations.  The timing for this event is currently scheduled to be between 7pm and 7am. 

Strong ridge top winds will also be a factor as these frontal bands approach.  

A cold front saves the day on Friday with freezing levels falling back to +-4000’.   Heavy snow is expected tomorrow and will slowly taper off on Saturday.  

The Long Range:  A high pressure ridge moves in on Sunday for a dry and clear start to the New Year.     

24hr Precipitation ending at 4 a.m: Today 24hr water: 1  snow: 7-10  (+ on upper mountain) Tomorrow’s 24hr water: 1.5 snow: 12-15 Trend and Timing: Snow increases today with mixed rain and snow expected between 7pm and 7am.  Heavy snow will fall through the day tomorrow.

24hr temperature ending at 4 a.m:  Low: 28    High: 36 Freezing level: 4000’ – 5000’ Trend and Timing:    Freezing levels will hold around 4000’ through the day and then spike up to 5000’ tonight.   Freezing levels will begin to fall early tomorrow morning (after 4am)

24hr Winds (mph) ending at 4 a.m: Base: 0-5 W/E Ridge Top: 10-20 W Trend and Timing: Pass level winds will flip from east to west with the passing of the fronts.  Ridge top winds remaining westerly and strong.

jM

6:15 Friday Dec 29th ABS

AC CALLOFF 8:00 Thur Dec 28th ABS

6:15 Thursday Dec 28th ABS

Mid Day Storm Update:

Time and Day:  0100  Wednesday

The approaching weather system is beginning to take shape.  Values from this morning’s forecast remain the same with some slight adjustments.  (see below)

Forecast:

Warm moist air out ahead of the approaching warm front will keep light precipitation falling through the day.  The main moisture event is expected after midnight with moderate snow starting around 2 am and continuing through the day.  

Freezing levels will rise have risen to 3500’ and are expected to hover there through the night.   Cool air to the east will help hold surface temperatures at or below freezing through most of tomorrow.  

The next warm front arrives late tomorrow afternoon/ evening.  Freezing level are expected to briefly bump up to 5000’ with a mixed rain and snow event expected tomorrow night. 

The good news is that a cold front swings in early Friday morning tapping into a nice fetch of moisture = Heavy SNOW.

Storm totals from Thursday 4am- Saturday 4am remain the same =  +-3” of water 15-30” of snow.   

24hr Precipitation ending at 4 a.m: Today 24hr water: .25-.5  snow: 3-5 Tomorrow’s 24hr water: .75 - 1 snow: 8-10 Trend and Timing: Light snow shower begins today and intensifies after midnight tonight.

24hr temperature ending at 4 a.m:  Low:22     High:26 Freezing level: 2000’-3000’ Trend and Timing:    Freezing level are expected to reach 3000’ this evening and then 4000’ sometime tomorrow.

24hr Winds (mph) ending at 4 a.m: Base: 0-10 W shifting E Ridge Top: 5-15 W shifting E Trend and Timing: Pass level winds will flip-flop from west to east over the next few days while the upper-level winds remain Westerly.

jM

MOUNTAIN WEATHER FORECAST

Time and Day:  0630 Wednesday

The Snapshot: Light snow showers today increasing tonight. Warmer with moderate to heavy snow finishes out the final week of 2017.   

** There may be a freezing rain component to these storms so be aware out on the roads.

The Science

Current Observations: It’s noticeably warmer this morning with a base area temperature of 22f. The RH is 93% and the barometer has dropped to 1018mb.  The winds along the upper ridge are westerly with gusts to +-10mph.  Satellite radar shows NW flow aloft with clouds and snow showers heading into the North-Central Mountains. 

The Forecast:  Weak NW flow will produce some light snow showers today with the first of two distinct frontal systems preparing to enter the region.  Snow will intensify late tonight/early tomorrow morning as the first (occluded) front moves into the mountains.  The second stronger and warm front arrives on Friday with moderate to heavy snow/rain likely. 

Freezing levels are on the rise and are expected to reach 4000’ tomorrow and inch up to +-4500’ on Friday. The big game will be how the warm air advection mixes with the leftover cold air. 

Storm totals from Thursday 4am – Saturday 4am could exceed 3” of water 15-30” + of snow.  

The Long Range:  The precipitation will linger into early Saturday morning with the rest of the weekend trending dry.  The New Year will likely start out dry as a blocking ridge of high pressure builds.    

24hr Precipitation ending at 4 a.m: Today 24hr water: .25-.5  snow: 2-5 Tomorrow’s 24hr water: .75 snow: 5-8 Trend and Timing: Light snow shower begins today and intensifies after midnight tonight.

24hr temperature ending at 4 a.m:  Low:22     High:26 Freezing level: 2000’-3000’ Trend and Timing:    Freezing level are expected to reach 3000’ this evening and then 4000’ sometime tomorrow.

24hr Winds (mph) ending at 4 a.m: Base: 0-10 W shifting E Ridge Top: 5-15 W shifting E Trend and Timing: Pass level winds will flip-flop from west to east over the next few days while the upper-level winds remain Westerly.

jM

8:00 Wed Dec 27th no ABS

MOUNTAIN WEATHER FORECAST

Time and Day: 0630 Tuesday

The Snapshot: Partly sunny and a smidge warmer today and tomorrow.  There is moisture with rising freezing levels on the way.

The Science

Current Observations: It is partly clear this morning with a temperature of 14^0f.  The RH is 92% and the barometer has bumped up a notch to 1020mb’s.   2” of snow fell yesterday with no new snow overnight. 

The Forecast:  A weak high pressure ridge passing over the region will provide some sunshine today.  Slow daytime warming will push temperatures into the 20’s with early morning lows still dipping into the teens. That is referred to as diurnal temperatures swings for you weather science geeks. 

The Long Range:  Let’s turn our focus to the end of the week and the weekend.   A low-pressure cell, churning in the Gulf of Alaska, will bring warmer temperature and measurable precipitation to the mountains starting on Thursday.   This system will pull warm moist air up from the SW – thus expected rising freezing levels and snow heading into the weekend.

We will have to watch the potential for a freezing rain component to this so stay tuned.       

24hr Precipitation ending at 4 a.m: Today 24hr water: .10  snow: trace Tomorrow’s 24hr water: .10 snow: trace Trend and Timing: Mostly dry with occasional light snow showers are expected today and tomorrow.

24hr temperature ending at 4 a.m:  Low: 14    High:22 Freezing level: 500’-1000’ Trend and Timing:    Diurnal temperature swings will continue through the next 48hrs.

24hr Winds (mph) ending at 4 a.m: Base: 0-5 E Ridge Top: 0-10 E Trend and Timing: East flow today with winds shifting westerly tomorrow.

jM

8:00 Tuesday December 26th No ABS

MOUNTAIN WEATHER FORECAST

Time and Day:  0700 Christmas Day.

The Snapshot:  Cold temperatures with light snow today. The rest of the last week of 2017 will remain cold with occasional snow showers. Warmer air arrives on Friday with potential measurable snow for the weekend.  

The Science

Current Observations: Light snow is falling this morning with 3” of poof-da that fell overnight.  The temperature is 12^of , the RH is 91% and the barometer is holding steady at 1015mb’s.   The winds have switched to westerly on the upper mountain but remain light and easterly in the base area. Satellite imagery has snow showers in the convergence zone heading towards Stevens Pass.

Forecast:  The low-pressure trough that brought us the snow will slowly drift east today. Unstable westerly flow will keep the chance of snow for most of the day.  Pressure gradients will begin to weaken over the next 24hrs allowing this cold and relatively dry airmass to remain in place through most of the week.   

The Long Range:  A stronger system is expected to bring warmer and wetter weather to the region starting on Friday.   

24hr Precipitation ending at 4 a.m: Today 24hr water: .25   snow: 1-3 Tomorrow’s 24hr water: Lt.10 snow: trace Trend and Timing: Lights snow will slowly diminish over the next 24hrs.  Tomorrow will be mostly dry.

24hr temperature ending at 4 a.m:  Low:  12   High: 20 Freezing level:0-500’ Trend and Timing:    Freezing levels will remain low.

24hr Winds (mph) ending at 4 a.m: Base: 0-5 E Ridge Top: 5-10 W Trend and Timing: Light east flow at the surface and westerly flow aloft will be the wind regime for the next 24hrs.

jM

8:00 No ABS Monday December 25

Hanukkah may be over, but tomorrow is Christmas Day AND Kwanzaa Eve!! At least there will be a little new snow to celebrate all the holidays with. 

Time and Day:  0700 Sunday

The Snapshot:   Cold with light snow developing this afternoon. Continued light snow Monday.

Current Observations:  No new snow overnight, single digits and mostly clear this morning with light east winds. RH is 82% and barometer is slowly dropping.

The Science:   The surface high pressure that brought us such a beautiful day yesterday will flatten out Sunday, allowing a weak frontal system to impact the area beginning Sunday afternoon. NNW upper level flow will maintain light orographic snow showers on Monday. A large Arctic air mass has sagged into the intermountain states to our east, the edge of which is being drawn into our area and providing for our relatively cold temperatures.

The current setup looks good for a minor lowland snow event; models have a couple of inches falling Sunday evening into the Seattle metro area. 

  

The Long Range: After light convergence showers end on Monday, Tuesday will bring a dry and cool day. Light snow showers start up again Wednesday, with a warm front potentially bringing rising freezing levels and moderate to heavy snow and rain Thursday and Friday. This will be one to watch as the week progresses.

24hr Precipitation ending at 4am: Today 24hr water:  .25-.5    Snow: 4-6” Tomorrow’s 24hr water:  .25    Snow: 2-4” Trend and Timing: Light snow beginning Sunday afternoon and continuing thru Monday.

24hr temperature ending at 4am:  Low: 6 High: 16 Snow level: 500 Trend and Timing:    Cold temps will continue Sunday and Monday.

24hr Winds (mph) ending at 4am: Base: Variable, then W 5-10 Ridge Top: NE, then W 10-20 Trend and Timing: Sunday morning will be calm with winds shifting to westerly in the afternoon and early Monday morning.     DV

Mountain Weather Forecast

Time and Day:  0745 Saturday

The Snapshot:   Cold and sunny today, light snow tomorrow night and Monday.

Current Observations:  3 inches of snow during the day yesterday, with no additional accumulation after 4pm. Single digit temps on the upper mountain this morning, with clear skies. RH is 90% and the barometer is rising.

The Science:   A weak high pressure ridge and dry northerly flow aloft will provide a beautiful winter day today. A weak Pacific frontal system makes its way into the region tomorrow, with temperatures remaining cold and light snow beginning Sunday afternoon. This one will not have much of a punch, but should provide some nice fresh snow for the holidays. With the low freezing levels Puget Sound may be looking at a White Christmas.

  

The Long Range: Currently Tuesday and Wednesday look dry with continued low freezing levels. Differences in the long range models vary, with snow possible by the end of the week and rising freezing levels.

24hr Precipitation ending at 4am: Today 24hr water: 0   Snow: 0 Tomorrow’s 24hr water: .25    Snow: 3-6” Trend and Timing: No precipitation expected today. Light snow beginning Sunday afternoon, remaining light to moderate thru Monday.

24hr temperature ending at 4am:  Low: 8 High: 18 Free air freezing level: 0-500’ Trend and Timing:    Temperatures will remain cool Saturday and Sunday.

24hr Winds (mph) ending at 4am: Base: Variable, then E 10-15 Ridge Top: E light, then 15-20 Trend and Timing: Most of Saturday will feature calm winds, they will increase overnight and Sunday morning.    DV