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10pm Wednesday...

It’s been awhile! I took a few days off last weekend (Happy New Year!) and then things got REAL busy weather-wise. Lots of extra work…

Of course 2021 ended very cold. New Year’s Day and last Monday were both the coldest of winter so far…only 34 degrees. And New Year’s Day included a lot of sunshine too! That was a very cold airmass pouring through the Gorge.

We ended up with 0.3″ on December 30th, which made for the snowiest December since 2008 at PDX

As always, some of you saw significantly more, some less. I ended up with 9″ at my home (1,050′) for the month. We never did get a big arctic blast across the entire Pacific Northwest, but the shallow edge of the really cold airmass punched down into northern Oregon a few times last week. PDX dropped to 25 on New Year’s morning Saturday. It was amazingly cold that morning north and east of Portland. The -22 appears to have been an all-time record cold temperature in La Grande.A surface low pressure system passing by to the north warmed us quickly Sunday night into Monday and we avoided a “transition snowstorm” in the metro area. But that storm also brought a HUGE dump of snow to the Cascades, Gorge, and blowing snow in northeast Oregon. Snowfall on Mt. Hood from Sunday evening to last night when things died down. 3+ feet is a big snow total for just two days on the mountain! At one point US26, OR-35, & I-84 (the entire Mt. Hood Loop) was closed to traffic.

With that cold airmass still locked in over north-central Oregon & the Gorge, big snowfall showed up there too. This was the biggest snowfall in several years.  Take a look at some viewer pics, this from Temira Lital in Hood River

Stevenson - Jodeen Lowrie

Stevenson - Kevin Waters

Looks like somewhere between 20-35″ fell in most areas from Bonneville Dam to Hood River. There are very few official observation sites in the Gorge. Hood River had a long term site all through the 1900s but those observations stopped around 2012. Bonneville Dam officially recorded 18.0″ & Cascade Locks 21.5″. When the January stats come in next month, we’ll see how much Parkdale officially picked up.

Lighter amounts fell both east & west of there. BTW, the all-time daily record at Bonneville Dam is 39″, Hood River is 47″, and Parkdale 37″…all in early January 1980. That Hood River number is also the record for the entire state! The TWO DAY record for Bonneville is 53″ during that 1980 event, so this week’s snowfall was the 3rd highest on record during any 2 day period. This WAS a historic event out there.

The very last thin layer of cold air is still in the Gorge this evening. I see 3″ new snow at The Dalles this evening, so it’s safe to assume 3-6″ has fallen deep into the Gorge around Hood River. That changes to freezing rain overnight as much warmer air is arriving overhead.

 

We are under a flood watch this evening, and it’s been raining all day. Tomorrow an atmospheric river will be aimed just north of us. Latest GRAF numbers look like this…

That’s a lot of rain, but nothing really dramatic in the valleys south of Longview. We should get some flooding north of Portland, especially on streams/rivers draining the Coast & Cascade ranges.

We’re headed into a much calmer weather pattern beginning this weekend. After 3+ weeks of cool and wet systems, upper-level high pressure wants to linger around the West Coast this weekend and all through next week. There’s no sign of low elevation snow for the next 10-15 days…the first half of January, and possibly through the 20th, will be mild. At this point it sure doesn’t look like a cold/wet January is in the works. But a lot can happen the last 10 days of the month…you never know!

I’m watching Friday morning closely too. Models want to develop a surface low offshore and have it race across the region, possibly just north of Portland = strong south wind? We will see. More tomorrow if that’s the case. We haven’t seen a windstorm in the western valleys yet this season!

That’s it for now, the 10pm show beckons… Chief Meteorologist Mark Nelsen

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It’s been a fun ride, if you don’t mind driving in a little snow and/or didn’t need to go anywhere the past week. We’ve seen several little (or big depending on location) snow events. Of course the largest and most widespread was Monday night through Tuesday morning. Officially PDX picked up 2.5″  Last chance is tomorrow...(click for more)

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9pm Monday...

We ended up with 0.7″ snow officially in Portland on Sunday. That was a mix of Sunday morning and again Sunday evening. That brings our winter total to 1.1″

Luckily no freezing rain so far and none in sight!

Today the southern edge of that cold arctic airmass moved through the metro area. That was right around sunrise. A northwest breeze kicked in, bringing the 25-28 degree air south. The high at PDX was right after midnight…34 degrees. It bottomed out at 26, now has risen back to just under freezing for most of us as the thin layer of arctic air mixes in with surrounding air. There’s no fresh supply of cold air coming from the north or east until Wednesday morning. So it’s plenty cold, in fact the 850mb temp of -9.9 degrees at Salem means it’s about 18 degrees at 4,000′ overhead! That’s also the coldest measured over Salem since the arctic outbreak of December 2013.

It’s snowing again tonight! I see a dusting all across the metro area and the boss says he’s got 1/2″ (fresh) in Lake Oswego. Most of the lower elevations west of the Cascades are under a Winter Weather Advisory. Anything over 1″ triggers that advisory. I remember in the 1990s when the criteria was either 2″ or 3″, but then after a few events it became obvious Portland can come to a standstill with 1-2″ snow, so an advisory typically means at least 1″ snow is expected. I think a Trace to 2″ covers it for tonight, although gut feeling says the majority of us get an inch.

I think roads will be mainly fine midday and tomorrow afternoon, assuming we really only do get less than 2″. Side roads in neighborhoods of course could remain snow covered all day

A “BC Slider” (a weak surface low that moves quickly down the Pacific Northwest coastline) is providing lifting, clouds, & light snowfall. The low is well west of Astoria right now

By 4pm tomorrow, the low has weakened and spread out a bit on the southern Oregon coastline. We won’t see much wind from any direction these next 24 hours because it’s so weak.

This light snowfall continues through tomorrow morning with flurries following the rest of the day. Temperatures remain below/near freezing most of the time. All models produce between 1/2″-2″ snowfall, most around 1″. The contour here is the HRRR. The GFS is much wetter/whiter…producing 3-5″ in the Salem/Albany areas by tomorrow evening! That’s due to another weak wave coming down south in the upper atmosphere later tomorrow, prolonging the precipitation. There is a decent “bust potential” in the lowlands with this event…

After the low dies to our south tomorrow evening, a fresh surge of that modified arctic air pours through the Columbia River Gorge. That should bring drier air, sunshine, and high temps only around freezing or so Wednesday. That will be our third day around the freezing mark. A chilly 12 days of Christmas indeed!

I’m watching the next system for Wednesday night & Thursday closely. All models agree that one more little “slider” comes down the coastline, but moves inland across the central part of Washington this time. That gives us a gusty southerly wind for at least a few hours that day. We’ll probably climb into the mid-upper 30s at some point Thursday with the warming onshore wind, but not before somewhere between 1-3″ snow falls.

That’s it for this evening…enjoy the snow! Chief Meteorologist Mark Nelsen

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9pm Sunday...

It’s tough to get “sleddable” snow when not much of ANYTHING falls out of the sky. That happened in much of the Portland metro area today. Lots of sunshine, sparse shower action, and very little precipitation. In fact PDX only recorded .05″ yesterday AND today combined! Officially we squeezed out 0.5″ of snow last night and early this morning. The daily total continues through midnight so that could change since we’re seeing plenty of snow showers right now.

I don’t think I saw a report of more than 2″ anywhere in the metro area (so far!) except out in the Hillsboro, Banks, Forest Grove areas. That includes Clark county and the western Gorge too. Most of the showers didn’t do much once they passed over the Coast Range. Of course with some sunbreaks and temperatures above freezing, that little bit of snow melted by early afternoon.

Remember I forecast Trace-3″ in the last few blog posts. Yet there was MORE snow than expected in a few places. Salem, McMinnville, Forest Grove, Longview, Lebanon, Albany. Models had hinted there would be some “training” of those snow showers bands and it did happen. But just in a few spots.

Someone was harassing me on Twitter about the forecast (always wrong, etc…) earlier. How would YOU handle a situation like this when some random spots will get a lot of precip and others will not? On a normal showery weather day hardly anyone would notice if we get 0.45″ vs. 0.15″ rain. The only difference now is that temps are near freezing = snow. Then everyone suddenly cares (for good reason) NWS decided to forecast for those highest numbers and issued a Winter Storm Warning to cover it. I chose to miss those high numbers and focused on what I thought most would get (Trace-3″), hardly mentioning the warning.

This evening the very cold arctic has made it to just north of Longview and east of the Cascades to Arlington.

That “arctic front” is now falling apart and we’ll just see a little filtering of that arctic air down into our area. We won’t be 23 degrees like what Seattle is seeing right now! The surface low and nearly dead arctic front is just south of us tomorrow morning

Snow showers have picked up a bit the last 2 hours and that means we still have a chance for a widespread dusting (likely) or even up to 2″ in the metro area (less likely). Roads are going to be very icy for the Monday morning commute!

The rest of the daylight hours Monday will be uneventful and most frozen roads slowly thaw. Main roads should be fine for the evening commute, just leftover slick spots where more than 2″ snow has fallen.

A “B.C. Slider” will be coming down the coastline tomorrow evening through Tuesday morning. That’s a little wiggle in the cold northerly jet that spins up a surface low pressure system and clouds/snow. A situation like this will be much different than what we are going through right now. This is a general/widespread light snow event. Temperatures will hover near freezing tomorrow night through the morning commute Tuesday. Most likely we pick up 1″ or so snowfall during that time. It’s unlikely we have a frozen mess Tuesday morning, but lots of slushy snow. Still, that’s not fun to drive on either! Then it warms above freezing again Tuesday afternoon for reasonable driving conditions many areas.

After another dry day Wednesday, another “slider” comes down the coastline. But that one is more likely to move inland NORTH of us. That’s important because a southerly breeze warms the lowest levels of the atmosphere quickly in this situation. We may go from snow to rain during that little precip event.

I sure don’t see a “snowstorm” with either of these two systems Tuesday and Thursday, but will be keeping an eye on things…

Enjoy the white start to your Monday!

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There are no “storms” headed for the lowlands west of the Cascades through Sunday (the 26th).  But the airmass will be cooling each day.  By Christmas Day, it’ll be cold enough for sticking snow at night even at the lowest elevations as showers continue to come and go.

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Mark Nelsen

Yes, for now (and probably for a long time into the future) I'm just copying the WordPress blog post into this KPTV-Friendly web site. Just keep commenting over on the old blog postings

Mark Nelsen

Mark Nelsen commented on Saturday Snow Update

Test. Anyone out there?