Worst “La Niña” Snowpack on Mt. Hood So Far, But Big Snow Ahead!

January 16, 2018

6pm Tuesday

Remember the excitement in mid-November when heavy snow was dumping in the Cascades and ski areas opened up quickly?  Things have sure changed in two months.

Today we passed an important threshold on Mt. Hood that tells us this La Nina winter is not behaving as it “should”…at least so far.

  • The amount of “snow water” in the snow pack is 15.4″ at the Mt. Hood Test Site 

Basically this means in the past 35 years we haven’t made it this deep into the winter season with such a low snow pack while a La Nina winter was in progress.  The sensors were installed around 1980; so we have 13 other La Nina winters to compare this one to.  Notice all of Oregon is in pretty bad shape right now:

You can read more about what we typically see in La Nina winters by clicking up top on the banner that says WINTER 2017-18 THOUGHTS.  These are winters that are typically known for abundant mountain snowfall and plenty of lowland rain.   But this year we’ve had a mix of a) mild/rainy systems, b) very dry period in December, c) warmer & drier than normal the 1st half of January.

Now it HAS been close to this bad.  January 1996 & 2012 were close, but then things improved the 2nd half of winter.  In fact 1996 was a poster child for how quickly things can turn around in the mountains the 2nd half of winter.  There was only 1″ snow on the ground at Government Camp on January 15th.  A snowy & cool pattern arrived two days later.  In just two weeks, 94″ was on the ground at Goverment Camp!  I remember those amazing two weeks;  cross-country skiing at only the 2,000′ elevation east of Corbett on about 2 feet of snow!

So what’s ahead?  Some good news!  My gut feeling is we don’t have a crazy 1996-style 2 weeks ahead, but I do see quite a turnaround coming the next 10+ days.  A series of colder systems that should bring many feet of snow.  Take a look at the ECMWF ensembles showing a steady accumulation of rain in the lowlands the next two weeks:

First, we are still in the warm air for tomorrow, so I see one last very warm day.  It’ll be our 9th day at/above 50 this month.

We’ll be within a degree or two of our 59 degree record.  Thursday a cold front moves through the region, dropping snow levels down to around 3,000′ by afternoon.  After that point just about every system during the following week will bring snow to pass elevations and above.   Note the GFS would imply snow could briefly dip into the Coast Range Saturday and/or early next week:

I see maybe a foot of fresh snow on the ground for Saturday skiers, then a bunch more for both Sunday and Monday.  Here’s the ECMWF estimate of snowfall up around 5,000′ through late next week.  3-5 feet, that’s a nice turnaround isn’t it?  I have plans to ski NEXT weekend, the 25th-27th…timing seems to be working out right!

The GFS shows similar totals…maybe 3′ in the next 7 days up there:

Down in the lowlands I think you know what this means…lots of wet weather and temperatures should cool back to normal.  Maybe even a few degrees below normal next week.  At this point I don’t see a setup for lowland snow/ice, or even a real strong storm.  That’s one other thing that’s been missing this winter (a series of strong storms) but that doesn’t appear to change in the next week or two.

To summarize, the 2nd half of January should be wetter and cooler than the first half, with some nice snowfall in the Cascades.  Things are going back to normal the next two weeks!

Chief Meteorologist Mark Nelsen


Record Warm Sunday, But A Rainy Week Ahead

January 14, 2018

8pm Sunday

Today was a “January Scorcher” with temperatures in the metro area running 10-15 degrees above normal.  We were just two degrees short of our 60 degree record

Todays Observed Highs OrWa 2017

Salem, Hillsboro, & Astoria all broke records for the date

Record Highs Cities

What a change from last year eh?  The first two weeks of January are the warmest in 12 years in Portland, meanwhile the first two weeks of LAST January were the coldest in 38 years.

Winter Snow_Ice Compare

The next 3 days remain mild, although temps will be much closer to normal.  Clouds thicken tomorrow and a cold front moves inland in the evening.  This will stop the snowmelt in the Cascades; it’s been in the 40s up there since yesterday morning at the ski areas.  Note the snow depth at the lower part of Timberline Ski Area (the SNOTEL site) is the 2nd lowest of the last 10+ years:

Mark Mt Hood Snowpack January 1

The good news is that we finally see a change coming for building the mountain snow pack.  Several much cooler systems arrive Thursday through at least early next week.  That turns things wetter in the lowlands, plus a bit cooler.  See the big drop in snow levels on Thursday?

ECMWF Snow Level From 850mb Temps

In the mountains we should finally, for the first time in over a month, see a rapidly building snow base.  Check out the morning Euro model run estimate of snowfall from now through Saturday evening; 2-3 FEET in the Cascades during that time.  Almost all of this falls after Wednesday:

ECMWF Snow Accumulation

These will be colder systems moving onshore, but they will be accompanied by “onshore” flow, which means a breezy west or southwest wind with each.  That’s why I don’t expect snow in the valleys for now.

As of now I’m not sure if this is “the big change” to La Nina conditions or just a week of cooler/wetter systems.  We’ll see about that.   To sum things up, I think there are several key points for the next 7 days:


Here’s my Government Camp forecast, along with snow forecast for the ski areas at Mt. Hood (lower snow #s are for Govy, higher #s up around 6,000′)

7 Day Forecast GOVT CAMP

Chief Meteorologist Mark Nelsen

Blustery January Day, But Beautiful Weekend Ahead

January 11, 2018

8pm Thursday

Today we had a nice little Pacific Northwest wet & windy day.  Neither the rain or the wind was too much.  Note the rain totals generally under one inch:

Rain Metro Today Databound

Peak wind gusts didn’t cause much damage either at the Coast (generally under 60 mph) or in the Valley (gusts 30-40 mph) as expected:

Wind Metro Peak Gusts Today

One thing that really stuck out though…the warm temps!

Today was the warmest since Thanksgiving Day in Portland.  We tied a record high of 58 degrees.  That meant mainly rain in the Cascades, except at the highest parts of the ski areas.  A cold front is moving through Oregon right now, but the air behind it isn’t very cold.  Snow levels will only come down to around 4,000′ tonight and Friday.  That’s the lowest we’ll see snow, since a much warmer airmass surges into the Pacific Northwest beginning Friday night.

A strong upper-level ridge of high pressure develops Saturday through Monday along the West Coast.  Note the ECMWF model showing heights WAY above normal


That gives temperatures between 50-55 degrees up around 5,000′.  Now if it was late March or April, we’d be forecasting high temperatures in the 70s for the weekend.  But of course it’s not, and the warm air doesn’t mix all the way down to the surface due to winter inversions+weak sunshine.

So how warm could it get?  Models keep pushing temperatures into the upper 50s or even 60.  That won’t happen in January.  But if we get the perfect setup of cloud cover all  Friday night (keeping temperatures warm overnight), then they lift north quickly and we turn sunny?  I could see highs in the mid 50s as a light easterly wind develops out of the Gorge.  I’ve gone for a high of 54.  Clear skies Saturday night mean a tougher break through the inversion Sunday, plus east wind looks stronger.  The result should be high temps close to 50, but it’ll feel like 40 on the east side of town in the wind zone.

Regardless of the exact temperature details for this weekend, keep in mind we have a MOSTLY SUNNY WEEKEND WITH COMFORTABLE TEMPERATURES IN JANUARY!  That’s almost unheard of, usually it’s sunny and cold (last year at this time) or sunny & windy/cool.

We have a period of wet weather coming up again next week, with rain arriving on Monday (MLK DAY) afternoon.   You can see that on the ECMWF meteogram (blue bars from left to right) for the next 10 days

By the way, there is no sign of stormy weather (a windstorm), flooding, or lowland snow/ice in the next 7-10 days.  We MIGHT get by with a snow-less January.  That is not unusual, check out the last 11 January’s.  Only 4 of 11 had measurable snow.  Apparently we may have had a little “overdraft” with those 8″ last year.

January Snow PDX

Enjoy!  Chief Meteorologist Mark Nelsen

January 2018: Much Different Than 2017!

January 8, 2018

9pm Monday

As I mentioned almost a week ago, the weather the past couple of weeks has been very S-L-O-W.  Check out how different the first week of the month has been compared to last year!

Winter Snow_Ice Compare

So far this winter (beginning December 1st), we’ve seen temperatures near normal, but it’s sure been a bit drier than normal.  Most obvious has been the lack of mountain snowfall.  You see all of Oregon is at/below 50% of average “snow water” for this date:

Snowpack Oregon Plus Facts

At this point last winter we were finishing up our 2nd ice storm of the season with two more to go.   That was the weekend snow then ice event (very similar to what just happened Christmas Eve).  The big snowstorm followed just two days later (a Tuesday evening).  So far this month is running warmer than the past 4 Januarys…yes, quite a change.

Looking ahead, we are still in a split-flow pattern early this week, with big rains falling way down in southern Oregon.  That continues the next two days, then a more organized Pacific frontal system moves inland Wednesday night and Thursday.  This gives us a nice rainy/windy 12 hours…ah, back to normal!

Then an upper-level ridge of high pressure pops up over the West Coast through the MLK weekend.  East wind SHOULD clear out the metro area for some sunshine Saturday and Sunday, although we’re still deep in inversion season so it won’t get much above 50.

There are signs of a pattern change which now appears to only be 8-10 days away.  Models and their ensembles want to develop upper-level troughing over the western USA or at the least a wet/stormier westerly flow.  I’m talking sometime after next Tuesday, depending on the model.   Note the ECMWF ensemble 500mb height anomaly for NEXT week and the FOLLOWING WEEK (the 2nd half of January) shows the lower heights along the entire West Coast and a much warmer eastern USA:

And the same two-week precipitation anomaly maps show a wetter than normal West Coast:

This WOULD be the change to typical La Nina conditions many of us have been looking for if it comes to fruition.  We’ll see.  The ECMWF is pretty clear, check out the 850mb ensemble chart; excellent agreement on those temps going down beginning on the 16th. NEXT week is consistently cooler than normal at 4,000′ in the Cascades.


This could mean we’ll finally start building a good base of snow in the Cascades.  What we DON’T see in the next 8-10 days is a pattern that would get snow/ice in the lowlands.  So it’s probably safe to say the first three weeks of January will not be featuring any snow/ice events.

Chief Meteorologist Mark Nelsen


Mid-Winter Doldrums; Split Flow and Drier Than Normal

January 2, 2018

9pm Tuesday

We’ve entered a New Year but the old and relatively slow Pacific Northwest weather pattern continues.

Much of December we saw upper-level ridging either overhead or off the west coast of North America.  Now the first week of January we are in a “Split-Flow” pattern where systems stretch apart as the move toward the West Coast.   Notice you see it in the forecast for Thursday PM and again next Tuesday from the ECMWF model:

The net effect is the same we saw in December…drier than normal plus a mild pattern in the mountains and coastline.

The past two days it’s been mild/warm in the mountains but chilly in the valleys as an inversion sets up.  It was just as warm at Timberline as Troutdale today.

With splitty flow expect weak Pacific systems over the next week.  Note though that the ECMWF ensembles give us about average rainfall over the next 10 days.


Somewhere around 2″ in the Willamette Valley is pretty typical for a 10 day stretch in January.  What we DON’T see is a setup for low elevation snow/ice, flooding, or a windstorm.

We are about halfway through our “storm season” west of the Cascades, so there is PLENTY of time for things to turn around.  But it sure doesn’t seem like a La Nina winter so far does it?   In 2013-2014 big snow in the mountains and regular stormy/wet weather didn’t show up until February.  That wasn’t a La Nina winter, but close, a “cold neutral” year.  We’ll see what shows up the next few weeks.

In the short-term we have a raging east wind this evening in the Gorge.  Crown Point gusted to 92 mph today and Corbett up to 79.  Most winters that’s about the highest it gets in either location.  That strong wind will continue through Friday morning, then back off dramatically later Friday.  Today was notable since at least some of the wind made it deep into the metro area.  Notice the 30-40 mph gusts in the West Hills and down into northern Clackamas county too.

Wind Metro Peak Gusts East Wind

There is a decent chance we see freezing rain in the Columbia River Gorge either Thursday morning or Friday as moisture rides over the cold air coming through the Gorge.  It will be too “warm” for freezing rain just about everywhere else west of the Cascades.  The only possibility would be overnight cooling and clear skies followed by sprinkles at sunrise.  The GFS says that could happen Thursday AM, ECMWF says no.  We’ll keep an eye on it.

Chief Meteorologist Mark Nelsen