MOUNTAIN WEATHER FORECAST

Stevens Pass Mountain Weather Forecast

Day and Time: 10:30am

The Snapshot:  Increasing rain and wind today with temperatures reaching into the 40’s.  Blustery wet weather will continue through the rest of the week. 

Note: The approaching warm front stalled its approach last night.  Moderate rain with rising freezing level is still expected.  

Current Observations:

Precipitation: Lightly raining. .53” of mixed snow and rain fell over night. 

Pass temperature: 38

Winds: 5-10 W gusty

Barometer: 1014mb’s and falling

Sky:  Overcast with pass level fog

Radar: Wide spread light rain showers.

The Forecast:  The next push of moisture is expected reach the mountains late this afternoon with moderate rain expected.  Temperatures have begun to rise with freezing level expected to peak near 7000’ later today.  Mild temperatures with several pulses of moisture will continue move into the PNW for the few days.

Long Range: There will be a brief break in the action Friday/Saturday with another wet system entering the region on Sunday.  

There are some early signs that cooler air from the NW will begin to mix with the incoming moisture early next week.  This is really far out, but the possibility of some snow early next week will be something I will be keeping an eye on.   

  

The Science: Yesterday’s high pressure ridge strengthened just enough to slow the approaching warm front.  The leading edge of the front is just making land fall and is expected to reach the mountains in the next 6-12 hrs.  This is now a slow moving front with an upper level shortwave disturbance leading the charge. 

Pressure gradients will tighten up with strong westerly flow expected to strengthen this afternoon. In other words, expect some strong persistent winds above 4500’.

For you true weather geeks.  Vorticities are not that impressive 12-15hPa,  UVV values are only 3cm/s.  These values point to an overall weakening system.  J  

Values from 4am today through

 4am tomorrow.

Precipitation: Today 24hr water: .75  snow: 0 Tomorrow’s 24hr water: 1  snow: 0 Trend and Timing: Light rain today increasing overnight.

Temperature: Low: 33     High: 42 Freezing level: 5000’ -7000’ Trend and Timing:    Freezing levels will peak near 7000’ this afternoon and remain around that elevation through tomorrow.

Winds Base: 5-15 W Ridge Top: 10-20 W gusty Trend and Timing: Winds will increase today with gusty ridge top winds being persistent.

The approaching storm

Nice fetch of moisture a foot.  

MOUNTAIN WEATHER FORECAST

Stevens Pass Mountain Weather Forecast

Day and Time:

The Snapshot:  Enjoy today because there a storm-a-brewing. Snow changing to heavy rain tonight, rain and wind tomorrow.    

Current Observations:

Precipitation:  Dry   

Pass temperature: 33

Winds: 5-10 W

Barometer: 1022mb’s holding

Sky: high clouds

Radar: There are few spotty showers of mixed rain and snow showing along the spine of south central Cascades.  

The Forecast:  Today will be mostly dry with the main moisture event arriving after 7pm tonight.  Mixed rain and snow below 4500’ with snow on the upper ridges are expected tonight.  Warmer temperature with heavy rain and wind can be expected tomorrow. 

Long Range: Several pulses of moderate to heavy precipitation will move through the region over the next 5 days.

  

The Science:  An impressive storm with strong pressure gradients and a SW fetch of moisture is tracking toward the PNW.   Freezing levels will hold around 4000’ as this warm front approaches.  Once the front passes east of the crest (+-midnight) temperatures will rise and the heavy rain will kick in. 

Wind.  Pressure gradients will tighten in the wake of the front and produce some consistently high westerly winds.  SW flow will keep the high winds at bay until it shifts more westerly tomorrow.  Models have 5000’ winds blowing 20-40mph starting after 7am tomorrow.  Winds could persist into Thursday as well.   

The general flow aloft will be WSW through early Friday. A shift in the jet stream develops over weekend.  This may allow some cooler NW flow to develop early next week.   

Values from 4am today through

 4am tomorrow.

Precipitation: Today 24hr water:.5+   snow: 1-3 Tomorrow’s 24hr water: 1-2  snow: 0 Trend and Timing: Mixed rain and snow starts after sunset with heavy rain expected overnight and tomorrow.

Temperature: Low:30     High: 38 Freezing level: 4000’-6000’ Trend and Timing:    Freezing level bottom out near 4000’ tonight and then sharply rise after midnight.

Winds Base: 0-5 W Ridge Top: 5-10 SSW.    Trend and Timing: Winds will be light today and increase after 4am tomorrow morning.   5000’ ridge top winds will be +-20mph once the flow shifts from SW to W tomorrow.

MOUNTAIN WEATHER FORECAST

Stevens Pass Mountain Weather Forecast

Day and Time: 10:30 Monday

The Snapshot: Light mixed rain and snow showers today with daytime temperatures peaking near 40f.  Tomorrow will be mostly dry with heavy precipitation moving in after sunset.  Wednesday will be wet and windy.

Current Observations:

Precipitation: Very light rain falling. There is 5” of new snow on top of the Cowboy Ridge. .68” of rain fell in the base area overnight.   

Pass temperature: 35

Winds: 5-10 W

Barometer: Holding steady at 1016mb’s

Sky: Overcast with patch fog

Radar: Scattered snow and rain showers over the mountain with heavier precipitation out along the coast.

The Forecast:  The next round of heavy precipitation will enter the mountains late tomorrow night. This will start out as a mixture of snow but will change to all rain by early Wednesday morning.    

Long Range: The storms will keep rolling in through the weekend with moderate to heavy rain anticipated. Freezing levels are expected to remain above Pass level through the weekend as well.  

Rain totals by the end of the weekend could exceed 5” of water

  

The Science:  The atmosphere will temporarily stabilize as a weak upper level ridge moves through today. Due to this ridging, most of the moisture will be confined to the west with some partial clearing east of the mountains.

A strong moist warm front moving towards the PNW is expected to make landfall late tomorrow night.  There is a pocket of cool air preceding the front which will temporarily drop freezing levels to +- 4000’.   Freezing levels will rise to 6500’ in the wake of the front.  Strong westerly flow with tight pressure gradients will produce heavy rain and windy conditions on Wednesday.     

Values from 4am today through

 4am tomorrow.

Precipitation: Today 24hr water: .25   snow: 0-1 Tomorrow’s 24hr water: .5-.75  snow:1-3 Trend and Timing: Light rain showers expected through 4pm tomorrow.

Temperature: Low: 30    High:40 Freezing level: 4500’ Trend and Timing:    Freezing levels will hover around the 4500’ today and then briefly drop to 4000’ tomorrow.

Winds Base: 0- 5  W Ridge Top: 5-10 W Trend and Timing: Winds will be light and out of the west through tomorrow.   High ridge top winds are expected to accompany the warm front late Tuesday night/ Wednesday morning.

MOUNTAIN WEATHER FORECAST

Stevens Pass Mountain Weather Forecast

Day and Time: 0900 Sunday

The Snapshot:  Mixed rain and snow today with temperatures in the low 30’s. With the exception of a few inches of snow tonight, there is no significant accumulation expected at Stevens Pass for the next 5-7 days.  Plenty of rain though.     

Current Observations:

Precipitation: Rain. 1.47” of rain fell over night 

Pass temperature: 34

Winds:  5-10 W

Barometer:  1010mb’s and slowly rising

Sky: overcast

Radar: There are bands of moderate to heavy rain moving through the region. The radar shows pockets of mixed snow and rain falling along the Cascade Crest above 4500’ with snow in the higher (6500’) elevations.

The Forecast: Intermittent mixed snow and rain showers start the week with another round of heavy precipitation and high mountain snow expected for Wednesday.

Long Range: The storms keep rolling in through the rest of the week with warmer temperatures. November will start out like it should – wet.    

  

The Science:  A cold front moved east of the crest about an hour ago.  Bands of moisture and cooler air are filling in behind the front. Freezing levels will fall to +-4000’ this afternoon with mixed precipitation falling through the next 24hrs.  Winds have shifted westerly and will be gusty through the day as well.

The high pressure system off the California/Oregon coast with westerly flow over the PNW will keep the storms rolling in.  Warm air advection will accompany a warm front late Tuesday.  Thus, models have freezing levels rising to +7000’ Tuesday night with another round of heavy rain expected to greet the day on Wednesday.  

How Will our Changing Climate Affect the Weather?

 Below is a 6 minute YouTube video that explains this climate/weather connection.   The jet stream plays an essential role in weather everywhere.   For PNW, being the first land mass for storms to hit, this is even more pronounced.    The jet stream is the Uber for storms developing in the Gulf of Alaska.   How fast and where the storms go is determined by the jet stream.  

https://youtu.be/TuHdPvnu3Ds

The key point: The effects of a  warming arctic will slow down and possibly re-direct the jet stream. 

MOUNTAIN WEATHER FORECAST

Day and Time: Thursday 10:00

The Snapshot:  Rain today, rain showers tomorrow, dry on Saturday.  Rain on Sunday.  High mountain snow early next week???

Current Observations:

Precipitation: Raining 

Pass temperature: 42

Winds: 0-10 W

Barometer:  1017mb falling

Sky: overcast

Radar: Rain tracking west and south of Stevens Pass. 

The Forecast:  The rain will increase today with temperatures reaching into the upper 40’s.  The rain tapers to showers through the day tomorrow.  Saturday will be mostly dry with some sun breaks.  Clouds increase Saturday night with rain re-entering the scene on Sunday.

 Long Range: Cooler with a chance of some mixed rain and snow is developing for the start of next week.    

  

The Science: The leading edge of the approaching frontal system is just making landfall. The precipitation is tracking west with the southern ½ of the state getting most of the moisture at the moment.  The temperatures have mixed to occlude the leading front so temperatures will remain fairly constant through the next 24hrs.   Increasing pressure gradients will bring and end to the steady moisture tomorrow.  A weak high pressure ridge will bring dry and partly sunny conditions to the mountains on Saturday.      

Values from 4am today through

 4am tomorrow.

Precipitation: Today 24hr water: +-1.75”  snow:0 Tomorrow’s 24hr water: .25-.5  snow:0 Trend and Timing: Heavy rain through the night, showers tomorrow.

Temperature: Low: 40    High: 50 Freezing level: +- 7000’ Trend and Timing:    Temperatures will dip to the upper 30’s tonight and rebound into the mid to upper 40s’ tomorrow.

Winds Base: 0-5 SSW Ridge Top: 5-15 WSW Trend and Timing: Winds will be fairly light and out of the SW today.  Ridge top winds increase tomorrow with gust + 20mph possible.

MOUNTAIN WEATHER FORECAST

 Day and Time: Wednesday 10:00

The Snapshot: The Pass got a few sprinkles of rain last night with the clouds starting to thin.  Today will be mostly dry with real rain moving in tomorrow.  If you are in need of snow, the Canadian Rockies are getting plenty.

Current Observations:

Precipitation: .10” 

Pass temperature: 40

Winds: Westerly 5-15 mph

Barometer: 1016mb steady

Sky: Cloudy

Radar: Dry with tomorrow’s rain off shore about 100miles.

The Forecast:  Moderate rain will begin around sunrise tomorrow with heavy rain expected tomorrow night into Friday.  The steady rain shifts to showers Friday night into Saturday.  Rain totals by Friday could exceed 3”.    

 Long Range: Saturday will be mostly dry with a few remnant showers in the mountains.  The next wetting system moves in on Sunday with a rainy period finishing out the month.  There may be a chance of snow on Monday, stay tuned.

  

The Science:  The stubborn high pressure will finally flatten and drift east over the next 24hrs. This will open the door for a series of fronts that will begin to charge toward the PNW.

The leading warm front will push on shore tomorrow with a strong SW fetch of moisture in tow.  A following cold front will cut off the steady stream of moisture late Friday with slightly cooler temperatures and intermittent showers filling in on Saturday.   Another similar event is taking shape for Sunday/Monday.

Freezing levels will remain well above Pass level through the weekend. There are some signs of a cooler airmass dropping freezing levels below 4000’ early next week. Stay tuned as those details become more developed.     

 

 Values from 4am today through

 4am tomorrow.

Precipitation: Today 24hr water: .10  snow:0 Tomorrow’s 24hr water: 1-3  snow: 0 Trend and Timing: Rain start after 4am tomorrow and intensifies through the day.

Temperature: Low: 35   High: 50 Freezing level: 6500’ - Trend and Timing:    Freezing levels could peak above 7000’ tomorrow afternoon.  Mild temperatures will remain through the weekend.

Winds Base: 5-10 SWS Ridge Top: 5-15 WSW Trend and Timing: Winds will be gusty at times but not significant.

MOUNTAIN WEATHER FORECAST

 Day and Time: 1000 Monday

The Snapshot:  Sunny today with temperatures peaking near 60f.  Light rain arrives tomorrow night.

The Forecast:  There will be one more beautiful day before a slow change in the pattern begins.  High clouds move in tomorrow afternoon with light rain anticipated after sunset.  The light rain will linger into Wednesday morning with a short dry/clearing trend expected for Wednesday afternoon.  Temperatures will remain on the mild side with daytime temperatures in the mid to upper 50s’ and early morning lows in the 40’s.

 Long Range: Moderate to heavy rain and cooler temperatures arrive on Thursday afternoon with intermittent shower expected over the weekend.   

  

The Science:  The northern jet stream is beginning to shift to a more westerly flow.  This will begin to weaken the high pressure that has dominated our weather for the past few weeks.  

Several low pressure systems with embedded frontal bands are beginning to take shape in the Gulf of Alaska. This will have some long term effect on our weather pattern with a likely shift to a more seasonal wet weather pattern.  Stay tuned as we head into what historically has been the PNW's wettest month of the year .  

Current Observations:

Precipitation: 0 

Pass temperature: 41

Winds: 0-5 E

Barometer:  1017mb’s steady

Sky: clear

Radar: clear

The BLOB is back

Persistent Alaska warmth this fall has brought back ‘the blob.’ If it lasts, it could mean a wild winter in the Lower 48.

By Ian Livingston

October 18 at 2:07 PM

Throughout early fall, Alaska has been oddly warm and pleasant. The cause of the freakishly nice weather has been massive high pressure anchored over and around the state. One of the strongest on record for fall, this sprawling dome of warm air has helped keep the usual transition to cold stunted.

Since days are still long in early fall across Alaska, the sunny September (and into October) skies have also allowed ocean temperatures in the Northeast Pacific to rise significantly, as well. This has led to a return pool of abnormally warm ocean water in the Northeast Pacific known as “the blob," and just in time for Halloween!

But scientists are unsure whether the blob will remain a fixture or fade away. If it manages to linger into the winter, the consequences for the Lower 48 could be profound.

[NOAA winter outlook: El Niño may mean stormy conditions in the South and Eastern U.S.]

Although the blob is focused over the Northeast Pacific and the Gulf of Alaska, it has played a substantial role in the development of extreme weather patterns over the Lower 48 when it has formed in the past. Generally, it has been linked to abnormally warm and dry conditions in the West, and cold and stormy conditions in the East.

When the blob is in place, the jet stream, which both divides warm and cold air and acts as super highway for storms, tends to veer north over the top of the blob. This results in a big ridge of high pressure forming over western North America, which brings mild weather and blocks storms.

The blob’s presence was linked to the persistence and intensity of the drought in California from 2013 to 2015. It also ″was blamed for contributing to 2015 being the hottest year on record in Seattle,” according to Scott Sistek, a meteorologist with KOMO in Seattle.

[Thanks to climate change, the weather that roasts California and freezes the East may thrive]

As the cold air displaced by the blob has to go somewhere, it then often crashes south in the East. Remember the polar vortex intrusions during the winters of 2013-2014 and 2014-2015? The blob played a role.

So what will happen to the current iteration of the blob?

After Alaska’s stunningly sunny September, warmer-than-normal conditions have persisted into October, despite some change in the pattern, which is now delivering more in the way of clouds and precipitation.

While the National Weather Service Climate Prediction Center is forecasting warmer-than-normal conditions for Alaska the rest of the month, the mega-high-pressure zone feeding the blob is expected to continue to shift and break down a bit. In its wake, a stormier pattern may take over, at least for a time. This would allow the waters where the blob currently resides to begin to mix better, perhaps ultimately diminishing or even destroying it.

“How long will BLOB Jr. last? At least as long as we have persistent high pressure over the north Pacific," wrote Cliff Mass, a professor of atmospheric science at the University of Washington, in a blog post. At this point, "it looks like things are evolving to a pattern with less high pressure offshore, so the BLOB should weaken.”

According to Brian Brettschneider, a climatologist in Alaska, even if high pressure persists, it may turn into a source of cold air rather than warmth given Alaska’s waning sunlight — which would weaken the blob.

Ultimately, it’s hard to say much conclusively about the blob’s fate.

The blob last showed up around this time in 2016. Back then, there was some thinking that it may lead to a new round of winter cold outbreaks in the East. That didn’t really happen, as the blob dissipated.

Blob or not, the damage has been done in Alaska, where drought persists in the coastal rain forest of the southeast, and it’s been an extraordinarily peculiar start to the cold season.

“The onset of autumn in Alaska — the wettest part of the year for south-central and southeast Alaska — has been slow to arrive by four weeks or so,” said Dave Snider of the National Weather Service forecast office in Anchorage.

Anchorage has yet to witness a freeze. Although the city could see its first freeze in about a week, that will be about 10 days to two weeks past the old record for latest, a substantial gap.

“Nome should have 20 freezes by now. This year just one," Brettschneider said. "Anchorage should have 20 days with temperatures below 38 degrees. This year, zero. So it’s not just the lack of a freeze, it’s that everything about the air mass is exceptional and persistent.”

Another oddity? Fairbanks has yet to see any snow so far this season, the latest on record. But history shows that the lack of snow so far means little with respect to what winter will bring

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Much like the future of the blob, the future of winter in Alaska is very much to be determined.

Brettschneider sees the potential for a perfect confluence of conditions to keep the warmth coming. Since September turned to October, a dominant feature has been a low pressure area in the Bering Sea. This is a conduit for driving relatively mild Pacific Ocean air into the state.

It’s still quite early in the cold season, even in the snowy north. For now, it’s a waiting game. Waiting for summer to finally end, and waiting to see what winter might bring. It won’t only have implications for Alaska, but for all of us.

 for pictures and graphs the full article is: https://www.washingtonpost.com/weather/2018/10/18/persistent-alaska-warmth-this-fall-has-brought-back-blob-if-it-lasts-it-could-mean-wild-winter-lower/?noredirect=on&utm_term=.373b0d35fa4a