No Snow In Sight For Lowlands

10:30am Wednesday…

The title pretty much sums it up, we’ve had no official snowfall in Portland or Salem this winter so far and I don’t see any in the next week or more.  A couple of days ago it was looking like we’d see our first snow dusting in weeks down below 1,000′ next Tuesday.  But now models have less moisture, slightly warmer atmosphere and the dreaded “split flow”. 

What is that?  In the case of next Monday-Tuesday, a cold system moves south out of the Bering Sea (between Alaska and Siberia) then dives SE towards the west coast of North America.  It’s looking increasingly likely that system will be headed mainly to our south, California and southern Oregon.  This is never good if you want decent precipitation here.  We just get the “leftovers” or light precipitation/showers.

Here is the 12z GFS ensemble 850mb chart, lots of lines!  (Click for a clear view)


An explanation for the newbies since I use these charts quite a bit…

Time runs from left to right.  Left side is this morning, far right side is the end of the model run, 16 days away or March 1st.  Note that all weather maps are in Universal Time, which means the new world “day” begins when midnight arrives in England.  The next calendar day begins at 4pm each afternoon here on the West Coast.  The “21 FEB” line is right at 4pm on the 20th, the 19 FEB line is 4pm on the 18th etc…

Temperature is plotted in celsius at the 850mb level, which is right around 4,000′ or so.  So you could think of the zero line going across the middle as roughly Government Camp

  • THICK BLUE LINE:  The actual high-resolution GFS run, also called the operational run
  • BLACK LINES: The 21 lower resolution “ensemble” runs, basically 21 other runs with slightly different initial starting conditions
  • THICK RED LINE:  The average of all the ensembles, or the “ensemble mean”
  • GREEN LINE:  The average for this time of year, that’s why it doesn’t move much

What can you learn from this chart today?  Quite a bit!

1. The average temp at 4,000′ in mid February over Portland is around 33 degrees

2. On the operational (blue) run, from Saturday afternoon the 16th onward about 10 days into the future the temperature is forecast to remain below normal…a cooler than average period ahead

3. We have high confidence in the trend through the next 7-8 days (through the 20th) since all the ensemble lines are clustered quite close together.

4. In the 12-16 day forecast timeframe, the operational run is quite a bit warmer than many ensemble members, you can see it way above many of them.  So confidence is quite low that the maps we are seeing (the operational run) will end up correct in that period.  This is common in the long-range, huge variability from model run to model run each day.

5. Wide variation beyond about day 8; low confidence beyond that period.

6. We need to see 850mb temps down around -7 in late February to even think about lowland snow.  That possibility is just about gone in the next 8-9 days.  Sure, one or two ensemble members are cold enough, but is it just cool and dry?  Could be. 

7.  There are still quite a few ensemble members wanting to bring those chilly temps back the last 4-5 days of February.  However, a week or so ago it was looking very cold for Valentine’s Day, snow levels down around or below 1,000′.  Then models backed off on the chilly air.

A few important caveats:

This model runs 4 times a day…that means a new chart comes out every 6 hours!

This is only one model, there are several others.

There is a huge amount of model forecast data out there nowadays, we really look for trends or grouping of good model data, not just one particular model.


Big Picture

I’m not putting a “Fork in Winter” yet, but it’s getting very close.  The chance of a big arctic blast, freezing rain, flooding, or significant snowstorm is fading away quickly. 

Will we get “sleddable snow” (1″ or more) in Portland the rest of the winter?  I’d put that chance at about 40% right now.  Yes, yes, I know last year we had our latest ever snowfall in Portland on March 21st, but there is a reason it was the latest ever, it’s very rare! 

Chief Meteorologist Mark Nelsen

92 Responses to No Snow In Sight For Lowlands

  1. germantownsummit1000' says:


  2. WEATHERDAN says:

    57 degrees and partly sunny here in Salem at 3:00 PM. What a really nice late winter day out there. It sure looks nice and mild the next two weeks. Spring training for baseball has begun and daylight savings time is only 24 days away. I really think we might hit 60 on Friday. So put away that snow shovel because you won’t be needing it until next winter.

  3. W7ENK says:

    Something strange, interesting, funny, what-have-you…

    A statement I made the day after Christmas:

    “I find it oddly coincidental that our cold weather switch got flipped to ‘ON’ on February 24th, both in 2011 and 2012. Both years led into cold and wet springs” … “It would not surprise me in the least to see that sudden switch to colder than normal temperatures somewhere around, oh… say, February 24th again this next year?”

    Guess what…?

    • Mark says:

      That is a very astute observation, and probably a decent assumption for the Spring. We’ve been locked into that nasty high pressure solution off the southern Oregon coast most of the winter.

      I wouldn’t be at all surprised to see a more western, if not northerly jet develop deep into the spring/early summer.

      Yet another year we wait for summer to begin the day after the 4th of July?!

    • Dave in SW PDX (235') says:

      Good call, Erik! This does seem like a “deja vu” February so far.

    • W7ENK says:

      I’m referring specifically to that February 24th date. 2/24/2013 is just 10 days away, and that cold anomaly looks to be taking shape again. Though it’s been there on and off all winter (as per usual), this time we may actually see it track inward. I know it’s just numerology, but it would still be interesting to watch what happens, see if anything unfolds.

    • Greg Carstens says:

      It is weird how February ever since 2000 or so has usually been dry. I sort of dread the month because of little weather action in it a lot of the time it seems in recent years.

      The NWS in both Portland and Seattle seem to be on the idea of a cold period right about the time that Erik mentions. Yes it would be really something to see the same type of thing happen three years in a row at the same time of the Fall-Winter season. Is it likely. The NWS has low confidence for now on the idea but it is being thrown out there for now.

      I don’t see stuff hitting the valley floors in the Willamette of Puyallup areas just yet because thicknesses appear that they will be still in the 530 range instead of a more acceptable 520 area for snow in a marine like environment. Snow down to 1,000 feet? A good bet. More for sure down below 2,000 feet some where, A cold mix above 500 feet and in pockets in the valley areas across the region might be doable in the colder early morning hours.

  4. Timmy_Supercell (Klamath Falls @ 4200') says:

    I understand Klamath Falls has 300+ days of sunshine per year, but not many February’s are this sunny.

    • Timmy_Supercell (Klamath Falls @ 4200') says:

      And my period of non-snow for over a month now.. this is typically an active part of Winter. Looks like spring already!

    • Timmy_Supercell (Klamath Falls @ 4200') says:

      The tops of the hills are green! They should still have some white coating on them….

    • germantownsummit1000' says:

      The hills are ALIVE!!!

  5. jimbo says:

    On this date in 95 snowed all day with east wind and temp in low 20s about 8 inches east portland. Next day was calm and clear and still cold. Absolutely gorgeous. Those were the days

  6. momof2kiddos says:

    Happy Valentine’s Day ❤

  7. vernonia1 says:

    is it really snowing up north? Langley and Wugrnd show blue even in Castle Rock. Wassup??

    • W7ENK says:

      Considering it’s almost universally above 40 degrees everywhere in the Western Valleys, and already pushing 50 in PDX Metro, I’m going to have to go with no. I see that blue blob on Wundermap too, not sure what’s up with that. Though I’m sure it is snowing, a few thousand feet up! 😆

    • vernonia1 says:

      thanks W7….my thoughts too but needed to check just the same 🙂

    • Wendy-Silverlake, Wa says:

      It was a little bit of a mix here this morning.

  8. Lol @ people still talking about snow this winter crying like a school girl coming out with just 8,9,10 days out posting their a chance of snow on the weather charts only to have it gets close to the time. Give it up snow not happening get ready for springtime winter is over for us.

  9. Timmy_Supercell (Klamath Falls @ 4200') says:

    So far, a spectacular February. Still no snow to speak of, ever since the second week of January. There was a brief 1″ on the 7th, but that melted quickly. Strong sunshine and mid 40’s last 2 weeks, with my first 50 on Monday! Even 52 just earlier this afternoon. Not that Klamath Falls has never had a 50 during this month, but what surprises me is the extended period of clear weather. I would normally still be receiving a decent snow pack off-and-on.

    • Timmy_Supercell (Klamath Falls @ 4200') says:

      On Tuesday, as our frontal activity comes back into the picture; snow appears to return to K-Falls. Forecast high of 37 that day. But after Tuesday, it supposedly quiets down again…. Overall not too active.

      I actually would prefer it to stay clear and sunny until the T’storm season kicks off 😀

    • pappoose in scappoose says:

      Let’s have that kick-off RIGHT NOW, thank you very much!

    • W7ENK says:

      300+ days a year, Klamath Falls isn’t called “Oregon’s City of Sunshine” for no reason. I wouldn’t be too surprised by it, you only get ~65 days a year without.

    • runrain says:

      Thunderstorms. Now we’re talkin’!

    • …just about anywhere east of the cascades gets that much sunshine a year…lived, worked and played around there for 20+ years….

  10. bgb41 says:

    2/13/2013 Oregon (All) Temperature Summary

    High:63 at AGNESS2( 247 ft) & Brookings (US 10(150 ft) & MEDFORD PORT #2(1858 ft)
    Low: 48 at Florence Municip(52 ft)

    High:29 at CW7477 Lostine(7002 ft)
    Low: 10 at CRAZYMAN FLAT (6100 ft )

    Largest Diurnal Change: 38 degrees
    CRAZYMAN FLAT (48/10 ) (6100 ft )

    Heaviest Rainfall:
    0.62″ at Government Camp(3600ft)

  11. Rae says:

    Maybe if they (the criminal geo-engineers) stopped spraying our sky with chemicals in order to keep the High pressure bubble over the Pacific and the Rain out, we may be able to stop this drought. Now that Wall Street is making money of weather events, we are seeing further corrosion of our country. People they are altering our weather on purpose. Look into this documentary, Why in the World Are They Spraying” . They are also causing us all a lot of respiratory problems. People have gone mad in this world.

  12. I’m not sure why I haven’t mentioned this before, but I haven’t had an above normal February precip wise since 2000!

    2009 skated by with just 1.03″ of precipitation, and this February could challenge that record low number for me.

    • EY (Oak Grove) says:

      2011 was the last time we had a “wet” February in Portland… And that’s only because, on the last day of the month, we got over 1.5″ of rain.

      Before then? It was 2000. The climatology of February has changed drastically… The average rainfall dropped from 4.18″ of rain to 3.80″ of rain… Insanely dry Februaries recently… Making me really angry.

  13. Sifton says:

    Godspeed for Thur. & Fri. after a slight tease today!!

  14. pappoose in scappoose says:

    “But for snow fans, it’s just a pep talk to not give up on winter just yet.”

  15. Jeff says:

    What we need is the arctic front to come down the NW passage ( classic recipe)..forget Frasier outflow although that would be an added bonus.
    That’s when weather forecasting can be a challenge ….it’s happened before…


  16. Joel in Albany says:

    Can someone please explain how things set up so perfectly for the South Valley last March. I had 5 inches and elevations around 400′-500′ had 9″. It was amazing but I really never paid attention to how things aligned so perfectly for this to happen. For 48 hours straight, snow was always coming down at different rates and didn’t accumulate much during the day but accumulated significantly at night. If it would have occurred in Dec – Feb, I can only imagine how much would have accumulated.

    • Ryan says:

      I would suggest looking at the archives from last March. Mark explains it well. Basically the cold front stalled right over the central/south coast and valley.

    • Kind of a deformation zone. With continuous heavy precip pulling down the freezing level. A very rare situation for sure. And we’re talking the end of March!

    • Mark Nelsen says:

      Both of those comments are correct, a stalled cold (stationary)front with steady and heavy precipitation for 24 hours or so…heaviest precipitation was over the central/south valley. Check out the blog postings from the 19th-21st last March. That WRF-GFS just nailed the heavy snow forecast in the south valley didn’t it?

  17. Mark says:

    Latest GFS runs throw a dash of hope into the long-range… Alaska into NW Territories appears to be trending towards having a healthy dose of cold in the extended…

    Let’s see if this is but one run only, a the beginning of a trend over the next few days.

  18. fishinpox02 says:

    The weather around here continues to bore, so I’ll just start dreaming of spring and tornado outbreaks across the plains. Nothing better then running live streams in the background at work.

    • Ron says:

      That’s what wet snow is–heavy, as compared to dry(er) snow with less moisture content? What was your point? Just wondering.

    • Ben T says:

      Ron, I assume that you are responding to me. What I mean is even though it is wet it can still accumulate pretty quickly. Wet snow is fun!

  19. TraciG says:

    Thank you Mark! That was the best explanation of how to read those that I have heard! Maybe every so often you could pick a topic to briefly explain? I know you are a busy guy, but this really helped. Being a teacher myself, I appreciated the simplicity.

  20. *BoringOregon* says:

    Dahhh darn split flow, I would not mind a mild spring but I would not mind a good snow storm to. This weather is so boring it makes me wan’t to move down to Oklahoma! I notice you guys where talking about weather Maps, this blog is really good she talks about a lot of weather maps like what you guys where talking about—

  21. Ben T says:

    Per NWS maybe Monday night-“However…an associated surface low is currently prognosticated to track toward the central or coast. If this track were to hold…a period of low level easterly flow could develop which might allow for a brief period of lower elevation snow. But confidence remains low this far out from the event…and model precipitation values are not all that significant. “

    • W7ENK says:

      “Prognosticated”? :facepalm:

      They’re running out of creative words…

      And how many times have they uttered the words “…confidence remains low…”?

    • gidrons says:

      “Confidence remains low” I’ll try that phrase at work and report back how well it works.

    • Alan says:

      Tomorrow they’ll say the track of the low has changed (no way!) so we won’t be seeing any low elevation snow event. An “event”? Like Nemo? Try Fail!

    • pappoose in scappoose says:

      Low confidence, is about as good as it ever gets for us. The usual snow in these parts isn’t forecast until it’s snowing, and then all you hear is how soon it’ll turn to rain!

    • Alan says:

      Or how the back edge of the moisture is showing up now. Shouldn’t last too much longer. Yah, we wouldn’t want it to stick or anything.

    • W7ENK says:

      Hahaha! 😆

      Too true!

  22. DCZ (Hillsboro) says:

    Did you really mean 40%? Reading your post I would have guessed you were leading up to say less than 10%.

    With only a couple weeks left, and models essentially saying no during most of that time, you still think almost a 50/50 chance of sticking snow this year?

  23. Lurkyloo says:

    What if we put a spork in it? Maybe confusion would lead to something other than blech, gloom, gray, boring, stupid, dumb, doo-doo head, funky, boogerish, lame, moldy weather. Let’s hope.

  24. WX Ninja says:

    If winter may be over then what season comes next? I’m almost sure it can’t be spring as we haven’t had one of those in quite some time….

    • Dave in South Salem (500') says:

      We will finally have a warm spring one can hope. I’d like to see 90 in May this year.

  25. Maybe next year……..

  26. Ben T says:

    The East has had their weather now it’s time for the West to have some fun, albeit less party-like. Come on ECMWF get colder!

    • W7ENK says:

      We’ve been saying that for what, three, four winters now? I’m losing track. At any rate, no such luck. Fact of the matter is, if you want 4 epic winter storms in 4 consecutive weeks for 4 winters in a row, you’ll have to move back East. Or, get North Korea to blast a hole in the Rockies somewhere about 50-55°N latitude, that might help.

  27. runrain says:

    Thank you, Mark!

  28. …sneaking in at lucky number 7….
    Mark, great basic chart reading primer!…

  29. Chris s says:

    Euro looks close to being good towards that feb 24th date….. Keep the fork on standby a little longer.😊

  30. W7ENK says:

    You could have gone with that headline in November, Mark.

  31. gidrons says:

    I could add one more tip on reading these. If its the GFS, don’t pay much attention past 7 days.

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