Portland’s official snow total so far this season is a HUGE 0.2″. That’s just a skiff of snow twice. We’ve seen more freezing rain than snow so far…
If you are hoping for some “sleddable” snow in the metro area, or anywhere west of the Cascades, that’s looking increasingly unlikely this weekend. But cold air IS on the way.
Highlights for lowlands west of the Cascades
- Mild weather continues through Saturday. Weather likely won’t affect your life much through at least sunset Saturday.
- Cold air will arrive on a gusty east wind Saturday evening with temperatures dropping into the 30s, and eventually upper 20s by sunrise Sunday.
- As the cold air arrives, will there be enough moisture around for sticking snow Saturday evening? It appears increasingly unlikely the two will match up for a widespread coating of snow. Models are in great agreement that it’ll likely be dry for most of us by 10pm at the latest, especially in the metro area. Temperatures won’t drop below freezing until later in the evening. By the time temperatures are down to freezing or below, we’ll probably be mainly or all dry.
- Will it snow at my house Saturday night? West of the Cascades anyone could see snow in the air Saturday evening, or mixed in the rain showers. But for reasons mentioned above, it seems unlikely you get real snow at your home.
- Sunday and Monday should be totally sunny days! But high temperatures will only be in the mid-30s…Brrr! Still, that’s 10 degrees warmer than what we saw in December. Plus, a breezy east wind Sunday (not too strong) will go calm Monday = it’ll feel more reasonable that day.
- At this point this doesn’t appear to be a historic or record-setting cold airmass. Partly due to extreme cold we’ve seen in the past this time of year, but also the airmass just isn’t historically cold.
This graphic shows what we DON’T expect…yes, I referred to 1″ of snow as a “snowstorm” in Portland. My point is just that anything more than that is unlikely
What’s new this evening
It’s nice that once again, 3-4 days ahead of a cold weather event, models are in surprisingly good agreement. The bitterly cold upper-level polar vortex will remain anchored over Hudson’s Bay the next week, but several cold “waves” of energy will rotate southward down the western side of that low. Notice that greenish trough rotating down through PACNW Saturday night. It’s moving quickly south instead of lingering right off the coastline. THAT is why models are drying things out so quickly; we don’t have any significant time spent with moisture riding over the cold air. These quick-moving shortwaves rarely produce any significant snow for us.
That was the GEM model, but other models look almost exactly the same in the upper levels of the atmosphere. That’s both timing and intensity of the upper trough. Models are still in some disagreement over how cold the airmass will be. 850mb temps on the GFS model only dip to around -8 to -9…barely even “arctic air”. Yet both the GEM and Euro have been forecasting numbers down around -10 to -15…much colder. This is where ensemble forecasts are very helpful. Both GFS and Euro ensemble average bottoms out around -9 to -11. It’s hardly a major arctic blast, but plenty chilly. Under sunshine that would give us a high temperature around 35 in late January. The GEM ensembles are a bit colder, around -12. That’s a bit chillier. Regardless, we will not be seeing a repeat of the low-mid 20s we saw on Thursday the 22nd of December. That day was brutal with cloudy skies, a few afternoon ice pellets, and wind gusts 40-50 mph blowing across the metro area. This should be far more tolerable.
The reason I’m really downplaying the sticking snow chance? As mentioned above this upper-level shortwave is really trucking along heading south Saturday night. Look at the dramatic change from onshore mild flow to offshore cold flow. Timing is slightly different on each model, but they ALL look like this. Euro 5pm Saturday…sunset. Rain showers and temps near 40.
4 hours later? 9pm… Cold east wind has arrived, temperatures have dropped, rain showers change to snow showers…and then…it just stops
5 hours after that? 2am Sunday all precipitation is gone and skies have gone clear. It’s breezy and chilly across the region as we drop below freezing.
Again, because of this no model is showing any real snow west of the Cascades. Possibly some wet spots that freeze for Sunday morning, but with that much dry east wind it’s possible roads just dry out before freezing.
With all this in mind, we come up with a 7 day forecast like this for Portland. Notice no FIRST ALERT WEATHER DAYS in red this time around. That’s because it won’t be crazy cold, wind won’t be extreme, and widespread sticking snow is not in the forecast. Assuming we go calm Sunday night and Monday night (without clouds), I could see as low as 15 in coldest outlying areas and 20 in the city.
Keep in mind, with cold air banked up against the east side of the Cascades Sunday…it’s going to be COLD at the ski resorts. Around 10 degrees those days.
This is the same time of year some of our coldest low temperatures have been set. Check out the late January/early February cold spell in 1950. That was Portland’s coldest month on record; interesting because the rest of that winter was quite mild. Warmer than normal in December, February, and March.
That’s it for now. Make sure you have your outside faucets covered up again (if you uncovered them) by Saturday afternoon. And turn off any outside water lines, or lines in unheated buildings/garages too!
Who’s ready for El nino?, Bom.gov.aus is really bullish for El nino by this summer and they are the most accurate too. Brace for impact some like it hot.
Wonder how cold it got in Burns, OR during the Great Winter of 1950? Unbelievably impressive numbers region wide then!
I thought I would look at the HRRR. As everyone knows, HRRR only goes out 18 hours but on 00Z, 06Z, 12Z and 18Z, it goes out 48 hours. These pictures are the last frame for the 00Z run. There is a possibility we could see snow but it could change.
I forgot, most of that moisture is coming from the East/Northeast. As you can tell, there is a lot more moisture to the East/Northeast.
Well this is a bummer. How do ya’ll think the foothills(Welches/Zig Zag area) will fair in terms of snow chances Saturday/Sat Night? Might head up that way to see some action ❄️
Still seeing indications in long range of a stubborn blocking pattern with high pressure building and weakening in frequent, repetitive cycles over Alaska. Each one presents an opening for cold. I’m not terribly confident we have strong prospects for snow the rest of winter but do see some hope with the pattern we’re in.
Seeing that too last, run has a 500 Vort pattern much like what is now on the table later on. Mountain man may be on to something?
The way I see it is nobody’s getting hurt or killed by our weather and I consider that a plus. I hope we get some snow and cold because it would be nice to look at. If not then oh well maybe next year. And Spring is just around the corner, and Spring is a nice time of the year as well. So let’s hope for snow and prepare for Spring. Peace.
We had a big arctic blast and snow in December so let’s not get greedy, I’m reading for spring.
Much ado about nothing per usual.
Komo 4 news is calling this a arctic blast and saying extreme cold temps are on the way for western Wa, lots of hype too get ratings up.
We have a chance for snow here next week (on the 1st) so maybe the groundhogs will stay underground. It’s not going to compare to the Feb.1989 event, though.
Very much. Maybe one pretty cold morning on Monday and that’s about it.
I haven’t found any reason to get excited about the prospects of this little glancing blow yet and I still can’t find much which is why I’ve been pretty quiet about it. I do know sometime we get surprised by a last minute development and I’m searching the models for that, but it really just hasn’t been there all along, not yet anyway. I suppose I’ll get a skiff of snow and a few pretty chilly days here, but what’s that even mean? I had two inches Saturday and there’s still a few patches in the grass… I might not even get that from this more advertised event and some of you got “surprise snow” that morning anyway. I kept hoping,come on a little more development a little further east (moisture) and same with the air mass, a little further west. However, it just doesn’t want to be this time. Maybe mid or mid-late February, I have a feeling even if not exceptionally cold, there’s one more snow chance for lowlands coming. The guy you all watch from Seattle, his so called “making you an expert on NA oscillation”, he doesn’t explain it correctly or completely at all, I watched and I like him, but he’s leaving a lot out. I would explain if someone wants to know, wants a lesson, but let’s just say, I don’t feel the meaning of doing so unless asked. However, I see an embedded highlight down about February 15th to 22th that might in fact be a perfect spot for an event. I’m not saying it will be, just that it’s favorable in the overall condition. Hope you all get a little snow fun even if it’s very little, and hope I at least get a little bit too.
Sorry guys and gals always a few typos on this phone. I never read it again check it until after posted, I don’t know, I just don’t.
Looks like we come out of this pretty quickly too. On to longer and warmer days!
I forgot, first 😉🤗
Thank you for the update Mark 😊 we’ll just need to see how it plays out 🤗❄️