Do You Think It Will Snow In Portland Again This Winter?

January 30, 2018

Here we are, hours away from the last day of January.  Today we hit 51 in Portland, our 18th day at/above 50 degrees this month.  That’s the most 50 degree days we’ve seen in January since 1994.

Mark January Warm Days

What a change from last January!

January Compare 2 Box Warm Winter

January 2018 is the 2nd warmest on record in Portland; records go back to around 1940.

Winter Snow_Ice Compare

In the 125+ year record at Salem, it’s the 3rd warmest January.  2010 and 1953 were warmer.

Now of course you remember we’ve had one snow event so far…3-6 hours of snow leading to the big (but timely!) 1″ total on Christmas Eve, then freezing rain later that night and again briefly on the 27th.  The areas in light blue on the map below saw 1″ or more, dark blue = 2″ or higher totals.  Note that west, south, and SE metro areas saw less than 1″.  Most of the Willamette Valley has seen no snow this winter.

Snow Totals Metro 2017 For Web

So what’s ahead?  Well as mentioned in the previous post there is no sign of low elevation snow in the next 10 days, which takes us into the 2nd week of February.

What about February snow IN THE CITY OF PORTLAND?  Take a look at the last 9 years:

Mark Snow PDX February

We have seen measurable snow in 3 of the last 9 years.  Although in 2012 most of us saw some snow late in the month so 4 out of 9 is probably more realistic.


Are we finished with snow at the lowest elevations?  I’m talking right in the lowest elevations, not in the hills or foothills of the Cascades.  Vote here:


Chief Meteorologist Mark Nelsen


Warm January & Early February; But Should You Unwrap Pipes & Change Tires?

January 28, 2018

7pm Sunday

This winter is not turning out to be a “typical” La Niña winter.  It’s been warmer than normal, snowpack has been well below normal in the mountains, and we’ve seen a real lack of storminess.  One other marker of a good La Niña winter is decent snow in the foothills, I’m talking 1,000′-2,000′ elevations.  Even that has been non-existent this year.  Other than the Christmas Eve snow (due to cool Gorge air), I’ve had only a 2″ snowfall once.

Each October I present a recap of the previous winter (Nov-early Mar) at the annual Oregon AMS Winter Weather Conference at OMSI.  As of now I see only 3 interesting events to cover:  1) Big east wind storm/episode in mid December in the Gorge  2) Christmas Eve/Day snow then freezing rain metro area and Gorge  3)  Big waves on Oregon Coast mid-January.   That’s it!  I can’t think of any other signficant storm.  No cold spells, significant flooding, etc…  And keep in mind anywhere south of Portland there was no Christmas weather fun.

About 10 days ago it looked like we might be “turning a corner” and heading into more typical La Nina conditions.  That would be lots more mountain snow, cooler weather systems, and about Looking back at the past week or so we’ve had a good run of rain and the best mountain snow since early December.

Folks, unfortunately it does not appear this was “the big change” we were looking for.

We’re headed back into an unusually warm pattern for at least the first week of February.  It’ll likely be a bit drier than normal as well.   This is disappointing not only for weather geeks like me, but skiers/snowboarders, and those of you that depend on snowpack to supply your summer water needs.

Snowpack DID increase substantially the last 10 days.  Timberline is up to an 80″ base, Meadows at 75″, and even Skibowl was finally able to open their Upper Bowl runs for the first time this season.  These numbers were higher before some rain and warm conditions returned this weekend.  Friday was the day to ski!  Even with the past 10 days of snow,  the snowpack across Oregon is far below normal.  Do you realize Willamette Pass Ski Area still hasn’t opened?  Mt. Ashland just barely opened this weekend.  There IS plenty of snowpack for the Columbia River this summer though, you can see the 100% or greater totals up in eastern Washington through Montana.  That’s good news.  But look at the terrible conditions once you get south of Mt. Hood, especially south of Santiam Pass.

Right now we have an upper-level ridge of high pressure temporarily centered overhead, you can see the anomaly (warm colors) centered over us.  That’s higher than normal “heights”

That produced some near-record highs and a very spring-like day today.

Salem hit 62, the 4th 60 degree day this month.  Only 2 other times has Salem had 4 or more days in the 60s since record-keeping began in the late 1800s.  It is our 3rd warmest January on record in Portland.  The one bit of good news is that the Tuesday/Wednesday cool upper-level trough is still on schedule to move overhead (mentioned in last Monday’s post), dropping snow down to around 2,000′.   So it’s fair to say we’ll get another 8-12″ in the Cascades.

But then an upper-level ridge becomes established either just to our west (late this week and weekend) or right over us (10-15 days from now).  That dries us out quite a bit, and sends much warmer air overhead once again.  Check out the slide show of the ECMWF:  It starts on Tuesday, then this Saturday the 3rd, Tuesday the 6th, Friday the 9th, and finally two weeks from tomorrow…Monday the 12th.   Dates are at the bottom right

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Looks like the ridge is a bit “dirty” which means likely not all dry, but lots of clouds and extremely weak (& warm) systems moving through.  Note it keeps the real cold air to the east.  The GFS model looks pretty much the same 16 days from now:

Now you may remember last week I mentioned it would only take a slight shift westward with that ridge to allow cold air in from the north.  That’s still a possibility and models have hinted at it over the past 3-4 days.  But as of this moment none of them are showing that scenario.


  1. There is no sign of a return to “real winter” conditions, no stormy weather or snow/ice/cold
  2. A very warm January is going to morph right into a warm start to February
  3. Cascade snowpack could take a hit later this week or beyond if we get a warm/wet system instead of a stronger ridge & sunshine.  The snow conditions last week were likely the best we’ll see (along with Tues/Wed this week) for the time being.
  4. If you have studded tires and pipes covered, DON’T TAKE THEM OFF.  That would be a poor choice right now.  Mine are staying on.  We can still easily get a cold arctic blast in the first two weeks of February, it’s even possible to have hard freezing the last two weeks of the month.  Example = February 2006:  18 in Salem and 22 in Portland under cold east wind around the 20th.

Watches vs. Warnings & The Great Cascadia Quake Anniversary

January 23, 2018

7:00pm Tuesday

Last night, while most of us were asleep on a quiet winter night, a powerful earthquake rumbled underneath the Gulf of Alaska.  It set off Tsunami warnings around the Gulf, and a Tsunami WATCH for the coastline of Oregon & Washington.  That watch was in effect from around 1:30 to 4:30am…again, while most of us were asleep.

There was a bit of confusion about this so let’s make sure we’re all on the same page with WATCHES vs. WARNINGS.  I think this graphic sums it up well.

Weather Watch vs Warnings

This applies to ALL weather events (snow, wind, ice, flooding, heat) AND Tsunamis as well.

So how about the case of the Tsunami watch this morning?  If it happens again, what should you do?  Go ahead and go back to bed, but make sure your phone, or NOAA weather radio is close by in case the watch is upgraded to a warning.

As for advisories, special weather statements, or public information statements, those are for less significant weather events.

By the way, Friday will be the 318 year anniversary the last great Cascadia “Mega-Thrust” earthquake.  It happened on the evening of January 26th, 1700.  Estimated to be at least a 9.0 somewhere off the coastline along the Cascadia Subduction Zone.

Earthquake Great Subduction Zone 1700 Event

It’s interesting that geologists didn’t know much about it until around 20 years ago.  They put together the pieces of the “puzzle” (#1-3 above).  Most interesting to me is the drowned trees in some bays.  The tree rings pegged the last growing season as 1699.  Good stuff.  You can read more about it here:

and the Wikipedia article which seems pretty reasonable:


Chief Meteorologist Mark Nelsen

Not a Typical “La Nina” Winter So Far

January 22, 2018

6pm Monday

Today wasn’t such a bad day with scattered light showers and a few sunbreaks.  No heavy rain, but it was our 8th day with measurable rain in P-Town

Temperatures were mild once again, our 13th day at/above 50 degrees in Portland.

Look at the change from last year!  The first 3 weeks of January have been the warmest in 12 years

This winter (beginning December 1st) has been a bit warmer and drier than average, not what we would expect in a La Nina winter.  Obviously a dramatic change the rest of this month and February could change that to “wet & cool”, but there’s no sign that is about to happen, at least the “cool” part.  There will be plenty of rain the next few days as a series of systems move inland.  And plenty of snow in the Cascades too!  Check out our 7 Day Forecast for Government Camp and Mt. Hood Ski Areas.  This could be the most snow we’ve seen in a week so far this winter!  30-50″ is possible by next Monday/Tuesday

What about in the lowlands?  We’ve only seen one episode this winter where the snow level was close to the lowlands; those 3-6 hours on Christmas Eve when we had the beautiful snow falling in the metro area.  There is no other time we’ve had it in our forecast and remember in the Willamette Valley you’ve seen nothing.   But there ARE two periods in the next 10 days in which we’ll see snow come down into the foothills, and maybe even higher hills in the metro area.  That’ll be this Thursday night/Friday AM and around Tuesday/Wednesday of next week.  You can see it on the ECMWF ensemble model map of 500mb height deviation from average.  First for Thursday you see the below average heights over the West Coast

Then for next Tuesday, the 30th…the same thing

So it appears we’ll wrap up January with at least some weather action…lots of rain and lots of mountain snow.  But what do we see BEYOND the next 7 days?

All models agree that we’re going “back to December”.  By that I mean some sort of upper-level ridging developing just west of the western coast of North America.  Drier than normal seems like a good bet after next Tuesday/Wednesday.  But EXACTLY where the ridge sets up is critical to our weather here.  If the ridge is quite close to us, as the ECMWF is showing right now for Thursday February 1st, we’re headed into an unusually dry period with mild temperatures for early February.

You can see that in the 15 day forecast for 24 hour precipitation from the ECMWF ensembles, see how the average drops dramatically after early next week

But just a slight movement to the west would allow cold arctic or modified arctic air to surge south through Western Canada.  Notice the 18z GFS has the ridge farther west, which could leave the “back door open”

Last night’s monthly run of the ECMWF shows the ridging very strong & very close to us in the week ending the 4th of February

And even stronger from the 5th through 12th of February.

Check out the precipitation departure maps for weeks 2-3-4 of that run…extremely dry:

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If that happens then winter is pretty much over.  That pattern would give us lots of sunshine and highs in the 50s.  That seems too simple and would be a strange start to the last month of a La Nina winter.

My gut feeling is that something is up and the ridging could at least briefly move farther offshore.  That would give us another “surprise” like we saw around Christmas with cold air sneaking in from the north.  Most likely that would happen in the first week of February.

For the rest of January though it’s all about rain and mountain snow.  Try to stay dry.

Chief Meteorologist Mark Nelsen

Does Your App Show Snow For Next Week? Here’s Why

January 18, 2018

7:30pm Thursday

Did you notice a snowflake or flakes on your app for about a week from now?  This is what our FOX12 OREGON app shows this evening:


All extended forecasts on apps are automated, so keep in mind it’s just computer modeling without human input.  Here at FOX12 we also put our regular 7 Day Forecast on the right side, you should always look there first.  But wait!  OUR forecast also has snowflakes in next Thursday.

What’s going on?

Thursday & Friday of next week we get a cool and showery weather pattern, just like today but maybe 5-8 degrees colder.   Today we were in the mid-upper 40s during the afternoon hours.

Jet Stream Forecast 2017

This isn’t an “arctic blast” sort of pattern; there will be no east wind pouring cold air out of the Gorge like we see in our real snow/ice events.  No this is the “wet snow” setup that frustrates so many of us.

AT THIS POINT it appears these showers will be accompanied by “onshore flow” or air flowing from the ocean inland.  That modifies the lowest part of the atmosphere enough that it’s really tough to get sticking snow (more than a dusting) down to sea level where most of us live.  But it is very easy to get sticking snow up around 1,000′ and above in this pattern.   In this upcoming pattern that app forecast is just right.  We’d typically see highs 40-46 in the lowlands and lows in the 30s in this setup and that’s our forecast too.

It’s hard to believe, but THIS IS THE FIRST TIME WE’VE HAD THIS PATTERN THE ENTIRE WINTER!  The only other time we’ve been close to snow in the lowlands was for about 4 hours on Christmas Eve…that’s it!  It’s been a mild winter so far.

So we’ll keep an eye on it, but it’s probably safe to say a lot of us will at least SEE snow in the air later next week, it’s just a matter of whether it sticks at your location.  If you live at/above 1,000′ it looks like possibly next Thursday or Friday you might see some snow on the ground.  But a lot can change in 7 days…

Chief Meteorologist Mark Nelsen

Big Waves On the Beaches Today

January 18, 2018

6pm Thursday

30-35 foot waves arrived on the Oregon Coast late last night as expected.  They continued to pound the coastline through the day.  There doesn’t appear to be much widespread damage, but the pictures and video have been amazing!  At midday a large wave smashed into the Sea Gypsy motel/condos.   The wave in action (courtesy of Joel Hernandez)



A few pics of the damage from David Willis:

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Take a look at a buoy about 30 miles west of Astoria

Wave Height One Buoy 24 Hrs

An important point is that this is SIGNIFICANT WAVE HEIGHT, not the highest waves.  These numbers show the average height of the highest 1/3 of waves.  So assuming we’re talking a 32-33′ sig. wave height, that means maybe 1 in 1000 waves passing a location could be as high as double that height!  In fact the NWS noted this buoy measured a 60′ tall wave around 1am this morning!

Where did the action come from?  FAR offshore.  A deep area of low pressure maybe 1,000 miles to our southwest generated a large field of southwest wind.  This is 48 hours ago:

OceanWaveHeight Observed

Then 24 hours ago the field of large swell was about to arrive on the coastline:

OceanWaveHeight Observed2

This isn’t quite as rare as you think.  It seems that at least once a winter we talk about 30′ waves, and the folks over at Portland NWS think we last saw conditions like this a little over two years ago, during that stormy December 2015.  That was about the same time as the Battle Ground tornado.

The wave/swell height is dropping now and should be down to around 20 feet by tomorrow midday & afternoon.

It’s amazing nowadays with social media how quickly great pics and video spread from the coastline to…the rest of the world.   20 years ago we would have just received an email with maybe a still pic…maybe.  Quite a change!

Chief Meteorologist Mark Nelsen




How About Those Crazy “Asperitas” Clouds This Afternoon?

January 17, 2018

10pm Wednesday

Thanks to all of you that sent it pictures of the neat clouds just ahead of the rain today.   This one is from Larry Cloud…


They are named ASPERITAS clouds (formerly Undulatus Asperatus).  The name comes from the Latin word for “roughness” or “harshness”.  In fact the name just changed last year as the World Meteorological Organization decided it was time to give them an upgrade with this very detailed explanation:

“Well-defined, wave-like structures in the underside of the cloud; more chaotic and with less horizontal organization than the variety undulatus. Asperitas is characterized by localized waves in the cloud base, either smooth or dappled with smaller features, sometimes descending into sharp points, as if viewing a roughened sea surface from below. Varying levels of illumination and thickness of the cloud can lead to dramatic visual effects”

There you have it.  I’ve seen these maybe once/twice a year in our area, which is pretty rare considering how many clouds we get in 365 days!

Here are some more pics from viewers…enjoy a little slideshow!

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Chief Meteorologist Mark Nelsen