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 
Hi Mark,
I go to your blog before anyplace else.
Thanks,
Eileen Hickey
Latest Euro holds snow off until Thursday evening.
NAM 3k is showing snow starting Thursday am and going all day in Portland
This event is on life support, let’s see if 12z euro can revive it….
Bust in progress as models trend away from the goodies. Not surprised. At least the SWE in the mountains should recover to near normal. Possible the models completely flip and go back to where they were 3 days ago but that will need to happen by tomorrow evening. Fingers crossed.
It’s not really a bust though. We knew someone from Eugene to Seattle was going to get slammed. Just so happened that it is likely not Portland.
I still think Portland has a good chance due to its location near the Gorge but it may end up being an East side event. I hope everyone gets in on it though.
LOL
Yeah, but when has that ever happened??
I would speculate that there is a better chance of that happening in such uncertain events such as these Artic air scenarios. I’m not going to take anything to the bank until Thursday morning and maybe not even then. These events are uncommon and very difficult for the models to be accurate any more than 1 or 2 days out. All the changes happening even now should tell you that. LOL
It’s Arctic, most people spell it wrong because they pronounce it wrong.
Yes Grizz, I know how to spell Arctic. Just not good at typing fast and relying on spell check way too often but thanks for noticing.
Late Feb 19. It was originally in Eugene 5 days out, Olympia 3.5 days out, then back to Eugene 1.5 days before
While 12z GFS was a little disappointing (though tropical tidbits still gives Portland about 6 inches of snow), WRF GFS 4 km shows Portland is still getting 5 inches of accumulating snowfall. Take that as you will.
Yea, but that quickly drops off as you get south of roughly a line from Oak Grove to Aloha. Wilsonville would get less than 1”. In SW Lake Oswego, I might get 2”. The whole NE metro area would score.
This is the most likely scenario to me. 8” in some spots in the NE metro and close to 0 in the far SW and SE.
I never said metro as a whole, just Portland. I’d agree with the assessment that Wilsonville would get less, probably about an inch, but otherwise it seems like the cutoff is right at Chehalem Mountain. This would make sense since Chehalem Mountain blocks any further east wind from going westward. Also, all the gaps are N/S orientation, rather than the W/E orientation of the west hills. The West Hills also has more gaps. This may trap the cold air more. However, if the east wind isn’t that strong or deep, then only east of the West Hills would receive anything. Wilsonville is south of the Chehalem mountain (Parrot Mountain geologically is part of Chehalem mountain), and to make it worse, Pete’s Mountain is also north.
We are supposed to get to 46 today? Still 30 here on my hill in Camas.
Teens now in Spokane with O’dp; NNE wind. A regional trend.
12z gfs insane. Will see what/if the euro delivers
Insane for you, hot garbage for most of the people on this blog (Portland metro).
Plenty of time the models to back off entirely… seen that happen many a time. The usual sequence…. Models bury PDX, then axis shifts N to Olympia, then Seattle, then poof gone like a fart in the wind
No big plans Thur/Fri so I’ll take the freezing rain as a “warm up” to perhaps some snow on Saturday. Just hope the power doesn’t go out. Otherwise interesting to watch the glaze build up.
No thanks! ZR is taboo. It’s the only type of weather I simply DO NOT want, ever. It’s so dangerous, destructive and downright deadly.
Pass on ZR. Tornadoes, floods, and mudslides too.
Unfortunately so, every model is showing quite a bit of freezing rain anywhere from Portland to Eugene. It all depends on where the snow/ice border is. That will move a lot throughout this event so I bet most of us wake up to at least a little fzr.
Ok. I take it back!
So we’ve literally had 3 years in a row where we’ve had a near miss with a blockbuster snowstorm(s). Bruh.
Nobody is talking about the freezing rain potential. Looks downright nasty for the southern metro area down into Marion and Yamhill counties.
Exactly! I’m shocked by that too. Hopefully, Mark and the NWS gang aren’t like us and totally miss the fzr aspect of this event.
Maaaan, the I-5 corridor from the interstate bridge to the Canadian border is going to get pummeled. Yes, the second shot on Saturday looks good for the Portland metro area, but I will always take a bird in the hand (Thursday into Friday) over two in the bush (Saturday and beyond). Not going to be fun watching all of our neighbors to the north enjoying epic snow while we sulk in cold rain or freezing rain.
These latest model runs will likely curtail Mark’s snow projections coming later today. Still not a total disaster and GFS and EURO give us a nice second shot over weekend. Not great but i’d hardly call this heading for bust zone just yet.
Waaayyy too early to make any definitive call—even for those who like to propagate the negative slant!
Keep dreaming…. King euro has been consistently putting the low too far north. No stopping that now unless there is a dramatic change ala Jan 2017 (although that had to do with moisture/duration as opposed to low placement). I mean I guess we only need a 50-100 mile shift south?
The Euro has trended just slightly south the past day or so. Also go look at the GEFS for the average low positioning. On the 12Z it is around Tillamook, which is a huge difference from the OP run. It is too early to call this dude.
Yep. Mark even said pay attention to ensembles over operational.
King Euro Operational is too far north, until last run. Ensemble median is still around Florence, which would equate to Corvallis North gets a snowstorm.
48 hours is “Waaayyy too early” now?
12z GFS…
12z takes the low even further north. Ball game.
A crisp and frosty 26 here in upper N. Milwaukie this morning.
Models are still sea-sawing. The Thursday event looking even more marginal with the low tracking North, by Hour 0 we may see snow as close as Longview, but that’s it. The following storms are in the window of where the first storm was at a day or so ago (in the models), so keep that in mind. See what that day+ did to the first storm? Still plenty of time for those following systems to shift and go anywhere but here.
I still think that with the first system coming in too far to our North, it will keep the cold air bottled up around Chehalis/Centralia, and by failing to reach PDX metro, that breaks the camel’s back, so to speak. Everything going through the weekend is contingent on that cold air getting here.
12z GFS running now…
The 12z GFS would agree with you. Brutal. The central metro area gets a dusting while the whole I-5 corridor from the state border to Tacoma gets pounded. All models shifting north now. So close yet so far.
To my untrained eye, the lows are too far north for anything more than an eastside snow/ice storm.
Are the high temps Friday and Saturday dependant on us having snow on the ground? Seems a bit on the cold side without having an arctic air mass over us, especially in mid February.
Morning models staying on track. I’m feeling better and better about getting something decent out of this one. I think we’re now within window that Jan ‘20 fell apart.
Likewise. Notice Bellingham is 27’ with NE breeze commencing now. A good index. Like all of us, just hoping that precipitation performs, once colder air arrives here. Hopefully within 48 hours of so.
The 12z NAM and 6z ECMWF are further north with the snow. I’m starting to feel like areas like mine in the S/SW metro are going to be really left out. Wilsonville south might get skunked. This is going to be a game of a few miles or a few hundred feet in elevation (or strong gorge influence). Latitude will be hugely important. NE Portland on a hill is definitely the place to be in the metro area.
GEM going further north now too.
I am referring only to the Thursday into Friday event with these past two comments.
The Euro and GFS are starting to align much better. Downtown Portland to Tacoma is the sweet spot. South of Wilsonville looks pretty meager. Huge gradient. I presume due to the east wind influence. North of Seattle, the totals drop off, but everybody not directly in the Olympics rainshadow still gets sledable snow in Washington by the time Monday is over.
I can tell the models are becoming realistic now. Yesterday the GFS wanted to dump, literally dump a foot and a-half on us. Now it is saying just shy of a foot on the 00Z. A more reasonable reality if you ask me. Not to say it couldn’t go bananas on us again.
The mountains went from 2~3ft of snow to 5~6ft of snow. This now seems again, like a more realistic scenario overall. And I’m so curious what the next couple runs say. The NAM 06Z is running right now.
The GFS went right back to crazy totals in the 6z. When the model flip flopping starts alternating between like 10 inches of snow and a foot and a half of snow, you know something good is likely. Also noticing all models seem to bring decent snow totals over weekend and not just Thursday-Friday, which is exciting.
I’m not waiting for 0z Euro ensembles to come out on the Euro since I need to go to bed at 12 for class.
3 days out so totals are now legal for me to post. Since details are not ironed out, I will put it with the disclaimer that things are highly volatile and by no means final. Also, the totals will be wide range, trying to encompass the entire reasonable range of possibilities, before narrowing it down tomorrow evening and Wednesday. Daily totals won’t come out until Wednesday.
I’m thinking somethings up Thursday thru Sunday. I’m not going the bullish 24 and snowy all day as some ensembles are showing, but I do think below freezing highs have a 60% likelihood of happening. Total snow range: 1-16″. Historic lows possible since the low high on the 12th (Friday) is 35°F.
I’m tired and fed up right now, so this did not have a lot of effort. Not from weather. Yes I did make it back to Sherwood, but barely. 5 miles from home, steering wheel started to shake uncontrollably, likely from the spare. Don’t recommend going 30 in a 55 with 70 being the flow of traffic (was on 99W between Newberg and Sherwood). Because of this, I had to cut my analysis short. Of course mercury is also in retrograde right now. Figures.
They came out when I writing this, I realize that. However weather.us hasn’t updated yet, so I don’t know the full details
ECMWF is looking better tonight especially for Oregon and more ensombles keep it cool and at least interesting into next week. Here we go, everything is looking better again tonight! Do I dare look at the GEM? I haven’t yet…
The 00Z EURO has the center of the low way south, near Florence. Big difference from just 12 hours ago.
Two things I noticed, either the models are running a little slower trying to process the complexity of the situation or WeatherBell is slower uploading the maps and data. Everything is coming in a half hour or even an hour sometimes behind normal. The other thing I noticed is the GFS is consolidating itself much better in the ensombles and looks pretty darn good tonight. I’m still waiting to see all the ECMWF but I’m hoping it’s good too.
Have almost a half inch of gropple on the ground by the way from a shower a little earlier by the way.
32F in the foothills already. I work outside everyday, today felt like a weather transition is underway.
Okay, except no. The transition you speak of is still at least 48 hours out. Tonight’s weather and overnight low temperature has – and will have – absolutely no bearing over the upcoming pattern. Were looking at a complete atmospheric replacement in 48-60 hours. The air here now will be hundreds, if not thousands of miles away by then, and the air hundreds, if not a thousand miles North of us will be replacing it, eventually, in that time.
Don’t jump the gun, son…
28F here this morning. Animals have a sense of upcoming weather as did people before computers. Unfortunately most seem to have lost that connection. And yes a transition is underway. It gets old seeing most of the people’s negative comments. This is the most exciting part of our weather in the PNW. Sit back and enjoy.
Nothing negative about my comment, in fact it was based in solid, sound science, nothing more.
I don’t doubt peoples’ or animals’ ability to sense changes in the weather, when it’s like 2 to 6 hours out. It usually has something to do with sudden changes in atmospheric pressure triggering some kind of arthritic sensation in one’s joints. There’s actually some scientific basis for that. But I do question when the claim takes place more than 2 days in advance. That’s just voodoo magic. But whatever floats your boat, man. Don’t let my skepticism stand in your way.
From reading this blog over the years I think Jason has very good insight into the weather and reading the current weather conditions that he directly experiences to see pattern changes.
Don’t you think this blog should be fun and light hearted…really no need for someone to try and be “King of the Throne” (it really does kind of get boring after awhile).
Be kind…have fun!
And I’m definitely not trying to be “King” of anything. Just keeping my head in reality.
The 00z UKMET is a fun one. Through Sunday morning…
Salem – 1’’
Portland (airport) – 24’’
This won’t happen, but some pretty gnarly gradients within a short distance certainly might occur.
Wow! Remember they’re just a bunch of frozen water crystals…in a blink of an eye everyone will have love on their minds…this also will soon pass!
A lot of you guys with negative frivolous commentary—it is just…well…negative frivolous commentary. (I know, all part of the game.😊❄️)
And if anyone is actually interested in “The Present”?!, temps are dropping nicely here this evening in inner SWPDX—now 38.8’ @ 200’ elevation. Precursor of coming days!
Gonna’ take a nice long hike tomorrow and think about it all!
Noticed that. Temps really dropping tonight and some east wind drift. Going to also enjoy an outing tomorrow in Happy Valley. Absolutely going nuts out here with all the new home construction, retail, new high school. Where are all these people coming from???
Honestly kind of “feelin it” about this one! ‘Will be so cool if we get a heavy hitter. Even if it only lasts a few days it will be great! And a reminder that: “It can—and does—snow in Western/Portland, Oregon! (Just not very often.)”
A few more inches Sunday overnight. Very solid 6-9’’ overall. Temps start moderating Monday afternoon.
Didn’t’ the mean to reply to Andrew with this comment…
The 00z GFS is looking much better. Brings the precipitation back. Transition from light sleet to light snow in the early afternoon on Thursday. All over by Friday mid-morning. 4-7’’ for the metro area by the time it wraps up. Stays well below freezing all day and gets really cold overnight. Beauty.
Second low goes into northern Cali, keeps valley cold….
Cold, but moisture?
Too far South.
It’s better than warm rain… and keeps valley primed.
It won’t even be as cold as late Feb 2011, I’m ready to mow my lawn now.
No one’s stopping you. 🤷🏼♂️
I would honestly be surprised if those 12z ECMWF snow levels end up being correct. Seems like too many ensemble members for both the GEFS & EPS that are much colder than that.
How cold will it get? Hoping for teens at least. Should be easily doable here in Bellingham.
Gonna be a garden-variety blast, not an epic, historic one. So it goes. If only top-tier blasts count, then you’re going to end up very disappointed most years.
If only “top tier” blasts count, we may never get one again, this far South. It’s been a hot minute since the last time we were graced by an actual Arctic front.
I was taken a bit aback at Mark’s comment about waking up to 40 Thursday morning. Most forecasts don’t even have us getting much beyond mid 30s for the whole day!
“Strong to severe disappointment.”
It takes some getting used to, but eventually you’ll get there.
It maybe when you get up, it’s around 40 but during the day, the temps fall into the 30’s. That’s what I’m thinking.
The 00z GFS is looking much better. Brings the precipitation back. Transition from light sleet to light snow in the early afternoon on Thursday. All over by Friday mid-morning. 4-7’’ for the metro area by the time it wraps up. Stays well below freezing all day and gets really cold overnight. Beauty.
I personally gathered Mark’s latest post in a positive vein—even amid his alleged “warm/benign” bias—at least for those of us in PDX. E.g. “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.”
We’ll see—right! A LOT going on!!!!!!
Yeah I certainly didn’t mean to mischaracterize his post and the very useful info therein. I think Mark makes a special point to counter the sensationalism that surrounds these events by emphasizing the other side of coin. It’s just a very different approach to someone like Cliff Mass who will actually discuss and show the more aggressive model runs that favor snow. Mark seems much more inclined to talk about the ones that don’t show snow. He leaves the more bullish forecasts to the people who are wrong more often. One additional note, these “gorge” events can still be incredibly profound. I’ll never forget in December 2008 driving up from Eugene to Portland. It was an historical snow event for Portland as we all remember and there wasn’t any snow on the ground until we’ll north of Salem! Eugene was in 40s by time Portland got nailed. Portland also stayed cold for more than a week.
That was the one time I actually thought the snow was never going to stop. Missed my flight to Phoenix for Christmas that year.
Unless king euro shifts south, W7 is right: Olympia and Chehalis score big time.
Repost from previous:
Welp, it appears that our snow is melting even before it falls…
18z GFS gives PDX metro and N. Willamette Valley just 1 inch of snow through end of run.
And it looks like that all comes from the first system on Thursday night. System 2 arrives as sleet/ZR, transitions to rain.
System 3 is rain only with a temp spike back into the upper 40s.
But then again, it’s the 18z. The reeree model that eats the boogers it picks out of the 06z’s nose… so take all that with a grain of salt.
…the drunk uncle will be asleep in the mashed potatos soon 😉
For what it’s worth, I believe GFS 18z ensembles are much more favorable for snow than the operational, as Mark notes, which feels like more of an outlier right now.
Yeah, funny thing about those outliers.
Most of the time, in retrospect…
It’s almost like I predicted the damn future… again.
🤔
Hmm, maybe because it’s the same thing every time?
Well, don’t spoil my secret!!
Western Washington scores again….
Too early to call. The Euro isn’t the word of god.
Most everyone else seems to think it is tho.
Hence the term “King EURO!”
😂🤣😂
Bring on the fork, so it can snow!
Thanks, Mark.
The 00z NAM and hi-res GEM look solid through early Friday morning. The NAM brings sticking snow all the way down to the southern Linn County as the low moves inland. The GEM is further north with the low, but south enough for all of Portland metro to get at least a few inches. The 18z ECMWF is a bummer. Only the far northern parts of the metro area would get even 1’’. On to the GFS.
18z GFS is a disaster.
00z gfs coming in now…. moment of truth
Cross your fingers, but don’t hold your breath…
Thank you so much for the update, Mark. I really appreciate you keeping us informed.
Bummer
As always, appreciate the update. But man, that was not a particularly positive discussion for snow. About 90% of that post was why we won’t see anything big. Hope that’s just the “conservative” approach coming out. Otherwise, my confidence in this thing materializing just went off a cliff.
Bbq at the bottom of the cliff! Don’t forget your mask.
…i’ve got the cliff bottom bbq well stocked for this one! 🙂