A Little Snow and a Lot of Cold This Morning

8:45am Wednesday…

Well that was fun; if you were out driving in the metro area around midnight it was a brief snowstorm with the east wind blowing/drifting the snow on the freeways.  That was the “snowiest” I had seen since last February.  The rest of the night was relatively quiet and accumulations have “behaved” according to the forecast so far.  That means a bunch of snow south of Portland metro again, but not much here.  It was a good night to be in Salem, Albany, & Eugene if you want snow.  The TRACE TO 1″ forecast in the metro area was good.

It appears little/no snow fell in Vancouver so far

and less than 1″ in the rest of the metro area up to this point.  The big difference this time is the frozen roads; a dry snow due to that cold east wind.  OFFICIALLY 0.1″ FELL AT THE PORTLAND NWS OFFICE (SO FAR).  That makes this the 4th measurable snowfall of the season, all in the past few weeks of course.

Farther south, several inches have fallen in the Willamette Valley.  I see an official 2″ measurement in Albany, then 5″ in Eugene followed by freezing rain (ice glazing) during the night.  Yuck.

WHAT HAPPENS THE REST OF TODAY?

• Snow showers should taper off, but they will continue off/on the rest of the day.  In the next hour or two anyone could still see some additional accumulation.  But after 10am it sure won’t be sticking to roads as temps gradually warm
• Expect a few sunbreaks later this afternoon with a cold high around 37 degrees.  That annoying & cold east wind will continue to back off as well
• EVENING COMMUTE WILL BE CLEAR

TONIGHT & TOMORROW

Light showers will continue to rotate inland through the area with breaks between.  The cold airmass will gradually modify the next two days.  That means IF temperatures drop below freezing tonight and IF showers show up between 11pm and 9am, anyone could get a skiff of snow on the ground again.  But don’t count on another snow or delay-day for the kids Thursday.

How much snow did YOU get?

Let us know in the comments.  Just location and snow depth.  If you are new, you have to be approved.  I’m looking for some totals around Salem, Woodburn, Newberg etc…

Chief Meteorologist Mark Nelsen

 

Light Snow Likely For Wednesday A.M. Commute

4:30pm Tuesday…

It’s been a bright and beautiful day, but very cold (for late February) and very windy.  Widespread wind gusts around 40 mph coming in from the east will continue tonight then die down quickly around sunrise.

We’ve been expecting a round of flurries for Wednesday morning, but models are just a bit “wetter” now which means we’ll get more than that.  It’s a very busy afternoon so I’ll make this brief

You see a variety of model snow forecasts here, but the basic idea is that we have less than 0.20″ of precipitation to work with.  If we were talking just rain, you wouldn’t even notice the difference between 0.05″ and 0.20″ rain.  But in “snow” that’s the difference between a slight dusting and 2″!  You see the forecast conundrum in this case; and why snow forecasting is so tough.

AM COMMUTE:  Winter Weather Advisory is up for Portland metro area down to Eugene.  Expect light snow showers, with little/no accumulation in some areas but up to 1” in others.  There’s the outside chance someone in the west/south metro could see 2”.

There will be some snowy roads here and there in the metro area but many areas where just flurries fall could be snow-free.  I wouldn’t cancel anything for now, wait and see how it looks in the morning, just like Monday

REST OF WEDNESDAY:  Snow showers and sunbreaks.  Roads will be fine after 10am since strong late February sun energy warms pavement quickly.  High around 37 as east wind goes away.

IN THE WILLAMETTE VALLEY:  South of Wilsonville to Eugene any of you could see somewhere between 2-4″.  This could be a better snow-producer for Salem than the last event yesterday.

Thursday through Friday we’ll continue to see mixed showers at times.  During the overnight hours it MIGHT be cold enough for sticking snow, or it may just be dry.  High temps remain around 40 with lows around freezing.

I’ll be on air at 5pm, 6pm, 8pm, 9pm, 10pm, and 11pm tonight.  See you there!

Chief Meteorologist Mark Nelsen

 

Historic Snowstorm Central and West-Central Oregon

9pm Monday…

Whew, what a storm!  I’ll get to the numbers in a minute.

First, the snow showers have been VERY SLOW to dissipate the 2nd half of today.  It appears they are finally finishing up according to radar.  That means about 1/2 of the metro area has wet roads, and about 1/4 has snowy roads (east metro).  Skies should at least partially clear tonight = Lots of ice around for the morning commute!

Tomorrow we’ll see brief morning clouds then afternoon sunshine.  Expect a very chilly day for late February; highs only in the upper 30s.  That’s due to a much stronger easterly Gorge wind spreading out across the metro area.  Gusts will likely reach 60 mph in the west end of the Gorge.  Brrrr!

Now lets talk snow numbers.  Here are the numbers, a reversal from the system exactly two weeks ago.  Eastside got a trace or nothing (until the dusting this evening), but west of the West Hills finally saw a decent snowfall

Our final forecast yesterday evening was Trace to 2″, so I consider that a pretty good forecast.  But the HUGE forecast achievement was models consistently showing a historic snowstorm in the southern Willamette Valley and into Central Oregon.  Remember yesterday morning’s WRF-GFS?  Not only did it do well in the metro area, but it forecast 12″+ in large parts of Lane and Douglas counties.

The actual numbers…

Trees and powerlines are down all over the place down there due to the heavy/wet 32-33 degree snowfall.  Lots of firewood in Lane County for NEXT winter!

CENTRAL OREGON

The numbers this evening are amazing.  Remember there was one wave of snowfall Saturday night and Sunday morning, then the rest last night through this afternoon.  It was really one long snowstorm.  I remember Madras once getting about 2 feet of snow during the January 1998 storm.  Some big snowfall during the 1992-1993 winter as well.  To see 20-30″ in some of the driest parts of Oregon is a big deal.

What a February!

Chief Meteorologist Mark Nelsen

9am Monday: West Metro Wins This Time! Mainly Dry Central, East, & North Metro

Looks like we just had a reversal of the snowstorm (or no snowstorm) from two weeks ago.  Checking ODOT cams and snow reports I see a snowy west metro

with lots of 1-2″ totals so far.  Also a 3″ report from the top of Cooper Mountain (Beaverton).  Good for all of you, that’s a nice snowy morning after getting hosed with the last system.

But east metro has been mainly dry or just a dusting with that dry east wind blowing.  Officially a TRACE has fallen as of 9am both at the downtown observing site and the NWS office in Parkrose.

Same thing in Clark county, although I see some snow filling in up there on radar

You can see it in the temperature map at 9am.  Where little/no snow fell, there was no evaporative cooling to drop temps to freezing.  Between 34-38 central/east/north metro, but it dropped to 32/33 where snow fell

You have to hand it to long-range modeling, forecasting SOMEONE getting nailed west of the Cascades.  Eugene has 10″ of snow sitting at the airport and there are reports of 10-15″ south of there around Cottage Grove and Lorane.    Pretty amazing that they could forecast a general location (somewhere in Western Oregon or SW Washington) getting a historic snowfall 5 days ahead of time.

Every highway west, east, and south out of Eugene/Springfield is closed due to falling trees, power lines, and heavy snowfall.  Both Willamette Pass and Santiam Pass are closed.  I also see 12″ at Redmond and one other report of 20″ in 24 hours just northwest of Redmond.  Whew!  Now that’s a snow day…

If you received more than 1/2″ snow let us know in the comments with depth and location.

If you are new to the blog, comments won’t appear until I approve them.  Just put it in once.

REST OF TODAY IN PORTLAND METRO

• Snow showers taper off as we go through the day.
• I expect less than 1″ additional accumulation and none of that will be on roads from this point forward.  I see ODOT road temperature sensors show temps have risen above freezing even at Sylvan and US26/OR217.
• A few sunbreaks this afternoon melt much of the snow that fell westside
• YOUR AFTERNOON COMMUTE WILL BE NORMAL WITH BARE ROADS

Chief Meteorologist Mark Nelsen

 

10pm Sunday Update: All Models Drier = Less Snow Metro Area

All evening models are in at 10pm.  They are all drier, which of course means less snow for the Portland metro area.  I’ve lowered the forecast a bit because of this

What does this mean?

1. I think Portland will pretty much operate “as normal” tomorrow after a light morning dusting.
2. If we only get 1″ of snow, roads will be just plain wet most of the time, and for sure by noon
3. Afternoon commute will be fine

All the other forecasts remain unchanged, a snowstorm just about everywhere south and east of the metro area.  Click on each for a closer view.

The final holdout (ECMWF) model came in just before 10pm and looks like this.  Seems pretty reasonable to me.

See you on the other side!  That would be the other side of the snow event, I’ll post sometime tomorrow morning

Chief Meteorologist Mark Nelsen

Snowstorm Monday Morning in Willamette Valley; Some In Portland Metro Too

11:30am Sunday…

Good news!  With less than 24 hours to go, models have come into very good agreement this morning.  They agree a 2nd winter storm will track through Oregon late tonight and Monday.  They also agree the storm center (lowest pressure) comes onshore around Cape Blanco Monday morning and moves northeast to around Baker City by evening.  Heavy snow will develop on the north side (within 100-150 miles) of this low center as it tracks through the state.  All models agree on this now so the only questions are: how far north do we get heavy snow (4″+), and how far north will ANY snow make it?

Here are my forecasts; reasoning follows after

PORTLAND/VANCOUVER METRO AREA FORECAST

(This includes all areas from St. Helens/Woodland down to a Newberg/Wilsonville/Mollala line)

• Rain showers late tonight turn to steady snow between 4-7am Monday and it sticks
• Expect a Trace to 2″ on the ground for the morning commute.
• Temps barely drop to freezing, so freeways/highways may not turn completely icy
• Light snow continues through the day, a total of 1-3″ heavy/wet/slushy snow by the time it ends late in day.
• Late February sun angle means roads warm well above freezing by 10am; I DO NOT EXPECT THE METRO AREA TO BE LOCKED IN FROZEN ROADS ALL DAY
• MAIN ROADS/FREEWAYS WILL LIKELY BE WET MIDDAY & AFTERNOON

I wouldn’t cancel ANYTHING until we see exactly what happens in the morning.  If we only get 1″ of sloppy/wet snow (low-end forecast), driving will be okay all day long.

COASTAL TOWNS & LONGVIEW/KELSO

• Either dry or just showers/flurries from Pacific City north and Longview/Kelso
• Little or no impact on your life there
• Trace-2″ Lincoln City to Florence.  Very wet/slushy, not too much impact on roads

WOODBURN/SALEM/SILVERTON (CENTRAL VALLEY)

• Heavy, wet snow 4am-Midday
• Snowy roads, especially morning
• 3-5″ total by afternoon, a snowstorm!

ALBANY/CORVALLIS/EUGENE (SOUTH VALLEY)

• A snowstorm!
• 4-8″ by afternoon, same starting time
• Snowy roads much of the day

COLUMBIA RIVER GORGE

• A snowy day
• 3-8″, heaviest middle/east end, lightest west end
• Gusty east wind blowing/drifting snow at west end

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TECHNICAL WEATHER GEEK DISCUSSION

It was great to see models fall into line the past two runs with that low pressure center.  It’s also nice that the WRF-GFS and ECMWF are much closer together with the snow totals.   Just looking at the precipitation forecast from the ECMWF you get the picture and see why there’s a much better chance for a big snow event central valley southward.  2″ of precipitation at Eugene but pretty much dry Astoria to Chehalis.  What could go wrong???  Praying that this precip shield isn’t 100 miles farther north = biggest February snowstorm on record, a foot of heavy/wet snow in the metro area!  Or that it’s 50 miles farther south in the end and we have a regular Monday with flurries/showers at times with NO snow.

This converts to a snowfall map like this, Eugene to Roseburg gets BURIED by a major snowstorm tomorrow, over a foot!  This would shut down I-5 and bring lots of power lines down in the south valley.  Remember I said SOMEONE between Olympia and Roseburg was going to get a big snowstorm?  At this point Eugene/Roseburg are ground zero.

Meanwhile the GFS/WRF-GFS had us dry (no snow) on last night’s run, but now has decided to turn things a bit wetter (more white).    That’s ZERO to 2″ metro area, and 8-14″ Eugene to Roseburg!

Here are a few more models…the GEM, GFS, HRRR, & RPM.  All produce very little snow in metro area.  Which actually means the ECMWF is the only model giving us significant snow in Portland.  So once again I’m trusting the “King Euro”.  Here are snow totals through 9am tomorrow, when all models except Euro say we’re pretty much done with snowfall

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Notice I’m hitting the “roads won’t be that bad with 1-3″ of snow” in the metro area tomorrow pretty hard?

That’s because the last few days of February we get a lot of energy from the sun even through thick cloud cover.  A good example is this morning.  Snow fell in many hilly parts of the metro area.  The pavement surface temperature at Division/I-205 and Sylvan/US26 both dropped to right around 32 degrees at sunrise with snow showers.  Yet at 11am they are both already up to 40-42 degrees.  The result is that less than 2″ snow, or snow that doesn’t fall very heavily during the day won’t be able to accumulate on pavement after about 9am all the way through about 7pm.  Now if it just DUMPS snow, (central/southern valley) it can still stick.  But at this point I don’t see that in the Portland metro area.

BEYOND TOMORROW AFTERNOON

Cold east wind continues to blow tomorrow night through Wednesday, so with any clearing, those wet roads freeze for the Tuesday morning commute.  Some models bring a little more precipitation over us Tuesday night or Wednesday AM.  We’ll see if that’s the frozen variety or not.  Clearly the northern part of the jet stream wants to hang on into early March.  We still have another week of cold weather ahead…

Chief Meteorologist Mark Nelsen

 

 

Winter Storm Watch: Snowstorm Likely Some Parts of Oregon & S.W. Washington

11:30am Saturday…

The coldest February in 30 years wants to go out with a bang!  A Winter Storm WATCH is up for much of the FOX12 viewing area, including north Oregon Coast, I-5 corridor, Gorge, Cascades, and north-central Oregon.

Why?

For the next two-three days, a boundary will be setup across the state of Oregon between cold/dry arctic air flowing south out of Canada (the chilly colors on the map), and TONS of moisture streaming in from the Pacific to the south.

Wherever the moisture rides over the cold air, heavy snow will likely be the result.  TWO separate systems travel along that boundary; one tonight and early Sunday, then another one late Sunday night and Monday.  Most snowfall tends to fall close to and north of the red line, within about 150 miles or so (highlighted).

ALL numerical weather prediction models (THE MODELS) are showing this setup and have been since at least Wednesday.  As always the exact positioning is critical to whether it snows at YOUR house or not.  If the whole zone is south of you, most likely you just stay chilly and mainly dry through the period (Seattle).  If it shifts north of you (maybe Eugene or Roseburg?), then no snow for you!

West of the Cascades, the first system coming through tonight and Sunday morning is a bit too far south to produce snow in most of Northwest Oregon, plus we don’t have an atmosphere quite cold enough either.  So snow level hovers around 1,000′-1,500′ through Sunday afternoon here.

The 2nd system for Sunday night/Monday is why we have a Winter Storm Watch up west of the Cascades.  That one tracks a bit farther north, sends far more moisture overhead, and pulls in a cold east wind through the Gorge as it approaches.  Take a look at the WRF-GFS forecast for 7am Monday morning.  Low pressure passing over Willamette Pass headed east and cold air pulled down from the north.  This setup is perfect for producing a snowstorm many areas west of the Cascades (and north-central Oregon)

If I were to look only at this model for Sunday night and Monday? I’d say no snow up at Longview and on the north coastline, just a Trace to 3″ in the metro area, but MANY inches Salem southward to Roseburg.  The GFS model is similar.

How about my favorite ECMWF?  It (along with the GEM model) buries the Willamette Valley in a major snowstorm by midday/PM Monday.  Many inches of snow from Portland to Eugene, a bullseye directly over Salem on that one.  GEM has even bigger totals as it brings the low from Florence right up to Salem.  By the way, the last 6 runs of that Euro have pushed a foot of snow into some location west of the Cascades.  It has been as far north as Olympia and as far south as Roseburg.  That’s some great model consistency showing that someone is going to get nailed westside.  The morning ECMWF shows the precipitation from late Sunday through late Monday.  Wow, that’s juicy (and white) south of the metro area.  You could get a foot of snow out of that much precip in the southern Willamette Valley, and only flurries at Longview and Astoria (with this model run).  This could be a historic February snowstorm somewhere in the Willamette Valley.

WHAT DO I THINK IS GOING TO HAPPEN?

We still have three more model runs before this event, so plenty of time to figure it out

• SOME OF US west of the Cascades between Longview and Roseburg are likely going to get buried by a beautiful, heavy, coat of wet snow between late Sunday night and sunset Monday; extra amazing that it’s happening on February 25th.  VERY late in the season!
• I don’t have a good feel yet for exactly where that’s going to happen, but it’s time to assume your life could get messed up by weather at least Monday morning, maybe for the following 24 hours.
• SOME OF US will get hosed by little or no snow, depending on where the low tracks
• We’re still two days away, but the NWS is thinking 2-8″ is the possible range right now in the metro area.  It could be below or above that number for the reasons mentioned above.  Seems like a good starting number though.  Just like the last event, we’ll narrow it down as we get closer.
• The Columbia River Gorge and north-central Oregon have the best chance at getting buried by two snow events, the weaker one late tonight and Sunday, then bigger Sunday night and Monday.  I can see 12-24″ falling out there.

IMPORTANT POINT

It’s late February folks!  Even if your town west of the Cascades gets 10″ of snow Monday morning, we’re not going to be in a snowy & frozen hell for the next week.  A few sunbreaks and snow starts melting off streets.  You are not going to be trapped in your home for several days.  Leave that kale alone… (west of the Cascades).

I’ll post again midday tomorrow as the drama continues to unfold…

Chief Meteorologist Mark Nelsen