7pm Monday…
As we head toward a big weather event, details start to appear in the last 2-3 days. We’re just entering that time this evening and here’s what I’m seeing…
A FEW KEY POINTS
- There is no guarantee we have a snowstorm coming later this week in the metro area. It’s just a possibility for now. That’s because at this point it’s too far out to determine how much we will see, or whether it’ll be a combo of snow + freezing rain. By tomorrow I expect us to know a lot more.
- We don’t know yet whether it’ll be a brief snowfall, or the city grinds to a halt for two days with a real snowstorm (Friday/Saturday).
- It’s unknown whether snow will make it down into the Willamette Valley (Salem/Albany/Eugene)
- A snow storm is very likely in the Gorge and Cascades starting Thursday
- Models are still in some disagreement about how much moisture we get (how many inches of snow)
- I do not see a big arctic freeze (temps below 15-20) in the western valleys of Oregon.
WHAT’S NEW THIS EVENING
First, the GEM (Canadian model) has backed off the extreme cold solution it was showing for a few days. That’s a nice change and brings it into line with other models. Second, the GFS model is all over the place, with operational runs showing almost all precipitation heading south of us…snowstorm for southern half of western Oregon but mainly dry and cold over the Portland metro area. A good reason to use ensembles. Those GFS ensembles are almost all wetter than the operational run, so I’ll ignore the dry-ish and extra cold GFS for now. I’ll assume we DO have significant precipitation on the way.
Third, cold air arrival timing has adjusted slightly. Cold easterly wind arrives in metro area at some point Thursday or Thursday night. That means no freezing Wednesday night and we wake up to 40 degrees or so Thursday morning.
So at this point the first chance I see for travel-related issues in the Portland area would be later Thursday.
The ECMWF has been somewhat stable for about 4 runs now, showing a classic Gorge and Portland metro snow/ice storm Thursday evening through Saturday. An approaching (weak) surface low pulls the cold air out over us, but not very far south into the Willamette Valley. If this is the case, Salem to Eugene could be left with only rain or spotty freezing rain. And there could be part of the metro area that only gets freezing rain…no snow. This is not unusual in these situations. Look at the latest run for late Thursday night
Less than 1/2 of the 18z ECMWF ensembles produce snow for Salem Thursday-Saturday, making the point that significant snow south of Portland is less likely than anywhere farther north or east. Sticking snow is far more likely in Seattle than Salem.
One other way to tell this could be mainly a Gorge and metro event? Check out forecast snow levels from the ECMWF. This says beginning Wednesday the sticking snow level stays above 2,000′ through the weekend???
That’s because we base this chart off of 850mb temperatures over Portland which typically works in our mild maritime climate. This says that without cold/dry air coming from the east, and deep enough to “fill the gap” in the chart above, snow won’t make it down to sea level late this week. Hard to get cold air that deep in the Willamette Valley based on what I’m seeing on the ECMWF.
That’s it for this Monday evening. By tomorrow afternoon I should be able to make some significant calls for who will or will not get snow. Should be able to start looking at amounts too since we’ll be just two days out.
Chief Meteorologist Mark Nelsen
FOX 12 Weather Blog 
Okay so I did a summary a little below, I was once a forcaster a long time ago much in the position Peat Parsons is today, so I have a degree from way back, and I just look at everything for fun now and try to share a little with you all. I don’t know if I should bother, it just seemed like fun. I live in a place where there aren’t any forecasts, so I make my own for my own location for myself. Mountain Man does live on a mountain, foothills of Mount Rainier. So that’s just a reminder of where I’m coming from. I’ve loved this blog since Mark started it 16 years ago. Wish you all great things in the coming events, but realistically some of you will be disappointed.
Oh hey, any of you guys have an opinion, should I include my half inch of gropple yesterday evening in my snow total? I keep records, but I’m not sure if that counts. I’m either at a pathetic 4.0 inches for the season or an also pathetic 4.5 inches for the season. I’m having an internal debate about it as it really wasn’t true snow, but it survived on the ground until late morning here.
IMO Grauple doesn’t count. 4.0 inches
Officially, according to NWS, graupel DOES count as snow. Oddly enough, so does hail.
The GRAF 4km paints Salem north with 1-4” of snow through Friday am. Low would be way south of where other models are indicating. Below freezing temps from Thursday mid-morning on.
GFS 18z ensembles good as well so not just operational outlier.
18z on crack. Paints 30 inches for Portland.
So beautiful out today. Hard to believe in 48 hours…
The fork has been put back in the drawer for a few more days 🙂
More like a week. There’s another system arriving on the weekend that could bring more wintry weather. We’ll see though.
Ahhhh, the memories!
Doesn’t hurt to hope for this again, does it?
😂🤣😂
You should probably bury some of that hope, but 3 inches, if that makes you satisfied, you might get that this time maybe a little more or less…
OOPS… I forgot, there’s some language in those…
Watch at your own risk.
There’s a Part 4, it’s more family friendly…
Winter storm watch just issued
The NWS plastered that watch like its paint on a wall, but I’m sure they’ll start downgrading soon.
Unless they believe the 18Z GFS will verify 😳
18z looking promising
Can we get an epic swing to the south like Feb 2019? Western wash has seen enough snow the past couple of years….
All of these misses are rubbing me the wrong way.
Looking more realistic now that Olympia sees another 30″+ snowfall when all is said and done, third time for them since March 2012. If that happens and Milwaukie gets completely shafted, I’mma be furious! All I want is a solid 3 inches of snow in my yard that stays in place for a minimum 24 hours. That’s all it takes to scratch my itch. Why is that always so hard to achieve around here?!?
Because you live in Milwaukee!!!???
D-dome.
Move out of that S hole
‘ee…Wisconsin???
Yeah, no. ‘IE, Oregon.
It’s like the extended se Portland that turns into the biggest banana belt of northwest Oregon, yeah sell, move for your sanity!
Move to western washington.
Mass just posted saying Western Washington gets hammered
Yes I knew that was coming as well as what I just said below! Was just going to say what you said, but you beat me to it.
Afternoon summary:
ECMWF is being very consistent now for several runs albeit slight difference each run of about 10 to 30 miles on the winter precipitation line and how much just north of that line. Portland Metro area gets snow after starting with sleet or freezing rain, areas down the valley, get little or nothing unless you are in the coast range or Cascade foothills. North of Portland gets lots of snow increasing more and more further north into western Washington. The incredible consistency between runs and ensombles gives me a lot of confidence, this will be the way things play out, sorry snow lovers down in the valley. Portland and everything east, west and north get something. We still have some chance there’s a low to the SW and NW at the same time and there will undoubtedly be a few more twist and turn solutions to come. Last thing I keep seeing a little more with every run on the EC, it likes the idea to maybe 30-40% chance NW Oregon and 50-60% SW Washington to continue winter precipitation of the wet snow type into Monday and Tuesday. This would be a different situation, with Arctic air pushing out into the Pacific off the BC coast and then turning back inland over Washington and Oregon. It’s showing this possiblity several times now. Moving on…
The GFS is like getting whiplash. Colder and dryer and cool and wet back and fourth with every run. But credit where it’s due, it’s consistent with being a yoyo for a week. It’s also being somewhat in line with the EC as described above about the winter precipitation line, when it shows precipitation. It also in my opinion, as Eric pointed out the other day, wanting to push the cold out to quickly. So it’s almost hard to say when this event is over how it performed, when it can’t decide what’s going to happen.
The GEM, there’s not much point in going into it, first we were going into an epic deep-freeze, now we’re already in a warming trend.
Last and important, we’re moving into the time to start looking at soundings tomorrow, a profile of the atmosphere straight up overhead. This will give us a much better idea of the precipitation type that makes it through the column of air to the surface.
Like all of us, I’ll look forward to Mark’s next update this evening!
What do you know…GFS 18z low tracks a little more south. it ain’t over guys.
And then the 18z GFS happened. What the heck?! Outlier compared to all other models, but I love it!
We had a surprise snow shower here yesterday-for once an example of it snowing when it wasn’t expected. Maybe tomorrow we’ll actually see some snow cover the ground, as forecasted.
Those 12z Euro ensemble totals were nice for Portland (city). Daily 10-90% (H/L)
11th: 39-41/24-30
12th: 21-33/19-29
13th: 22-34/17-27
14th: 26-43/18-34
15th: 28-47/21-42
Peak Snow Depth: 1.92-10.9 inches
Mean
11th: 37/27
12th: 27/23
13th: 27/23
14th: 33/25
15th: 39/31
Peak Snow Depth: 5.09 inches
❄️❄️💖💖❄️❄️
cough 💥kale run 💥
LoL!
Glad you made it home relatively safely, Tanis! Thanks again for the posts.
And as I will always say…let’s do this!
This is looking more and more like a Washington event for the lowlands outside of the gorge. The 18z 3km NAM highlights demonstrates it well. The trend is brutally clear at this point. Heck, when it’s all said and done, maybe the low will come in around Forks.
I am starting to get very concerned about the freezing rain possibility for parts of the metro area westward to the coast range. Huge potential for disaster with abundant of precipitation, below freeing surface temps, and ”warm” air aloft.
Freezing rain – the Subaru killer – the only thing worse than a mild winter with no snow. I hope you’re wrong, but based on what I saw on the Euro, you might not be 😦
850mb temps near portland don’t climb much above freezing if at all and you typically look for freezing rain when there is a bigger disparity between upper and lower levels but some areas south metro could definitely see freezing rain. Something to watch for definitely.
Yeah, with onset of moisture we are still above freezing though temps crash shortly afterwards and the entire column is freezing or colder and pretty well stay that way until daytime Sunday.
I’m not seeing a ZR event here. Maybe some sleet or rain/snow mix. I’m just paying attention to the GFS though.
Long, long-time lurker. I get it. Snow is cool but ultimately, it’s a pain in the a&$. Most of us have to get to work and for myself it means chaining up a fire engine. It’s not fun.
It’s always interesting to see the emotional highs and lows in here.
Bring on spring and summer
Haha this comment section is more dramatic then it has ever been! Opinions are all over the place; whatever the GFS has must be contagious.
Once again South Metro looking to get sawdusted. Lame. What’s the deal with that? Why does Tualatin/Lake O/West Linn/Wilsonville typically get far less compared to say Forest Grove or Banks which are further away from the freezer door?
People get emotional when the weather doesn’t go their way.
The low sets up to far north, allowing southerly winds to prevail. Secondly. If that’s the case and Forest Grove gets “birdied” it is due to the fact they are A. A bit further north, this not a much of the southerly impact, and most importantly B. The east cold+dry air flows west and piles up against the coast range, acting as a dam. Thus they get the snow.
Hope that helps.
Really it’s point B that I’m curious about. I’d like to see some kind of topographical map with the typical air-flow marked from the Gorge towards the Western portion of the state. If anyone has a link handy, that would be cool. Otherwise i’ll just use my imagination
It’s especially frustrating because of the complete lack of winter weather we have had this year.
I wouldn’t be surprised to see most of the Willamette Valley stuck in the 40s with a south wind throughout this whole thing. At least the Portland metro area should get some cold temps with at least a decent chance at a bit of something frozen.
On the bright side, the mountains will receive copious snow and we will all get a a lot of precipitation. That is still very much needed.
Seems to me we still do get snow. Albeit isolated to the metro area north and maybe not a 3-day snowpocolypse that everyone is wanting.
Better than absolutely noting and we still have 36 hours for this to evolve.
I never knew the comments section of a weather blog could be so highly entertaining and filled with more drama, twists, and turns than a mountain road!
So much bickering, who will end up with egg on their face? LOL.
Good grief! Talk about disparity in peoples renditions! Doesn’t Mark teach ensemble means?!
For myself I’m going with the GOLU. 100% accurate. All the others are highly suspect—especially when linked with subjective bias—so very evident on this blog (I get it—partly driven by frustration,)
Anyway back to the GOLU. I’ll be checking it frequently today, Wed., Thurs., Fri., Sat., etc.
At the moment it’s showing hazy sun. And my thermometer reads 34.3’
Time to take a long hike and forget about everything!
GOLU RULES!!
12z euro indicates that it’s time to throw in the towel. ‘Twas a good run.
Not really sure where all this “bust” talk is coming from. The models have been fairly consistent, if marginally worse than a day or two ago. EURO operational and ensembles still indicate a fairly potent snow event Thursday-Sunday. They just have slightly less happening Thursday and smaller totals generally (but 6+ inches is still legit in my books). GFS and NAM continue to be very bullish. No sign of major letdown yet. I think it would help credibility of some commenters to wait until the models actually validate the bust narrative. I’m a massive skeptic and am dreading a turn for worse but models haven’t gone that direction yet thankfully.