A Very Cold Night Tonight

We have a very cool air mass sitting over us.  Even under sunny skies we just barely made it to 40 at the lowest elevations today.  The top of the West Hills just scraped above freezing, and at the top of our TV tower (1800′), it stayed below freezing.

Drier air has been gradually working its way in from the north and also mixing down from above.  Dewpoints are in the 20s all across the metro area and we’ll probably see them even lower tomorrow, down around 20 or even upper teens.  Wind will be a non-factor tonight as well with only 1 millibar northerly gradient from Olympia to Eugene and a very light westerly gradient through the Gorge.

As a result, temps will be in a free fall the next few hours.  All of us should be below freezing by 9pm, even in the city.  Coldest spots may drop into the upper teens, with the main city areas into the mid 20s.  So far this season PDX has dropped to 23; I think we’ll just barely stay above that tonight, but tomorrow night could be a 20-23 degree night out at the airport with an even drier air mass.  Here are last night’s temps:


Watch out for freezing fog later tonight.  Tonight we’ll see more FROST on the roads (although some black ice is still possible) since roads will freeze first, then the moisture in the air will go straight to the solid state.  With some fog, clear ice is possible too as the water droplets freeze to those cold roads.

Not much happening otherwise through the foreseeable future.  The only forecast issue next week is whether we get stuck in fog at the lower elevations.  Common sense tells me we will, even though mesoscale models don’t show it.    I see one forecast sounding for 7am Wednesday shows 20s in the valley, but around 55 degrees at that time at 3,000′.  THAT is what we call an inversion.   With no significant pressure difference across the Cascades, or north to south for that matter, it’s extremely difficult to believe we won’t get locked into low-level moisture and muck.  MAYBE initially starting with this drier air will help…maybe.

Other than that, big ridge of high pressure remains over us through the next 10 days while very cold weather plunges out of Canada and into the eastern USA.

Here are the 12z ECMWF and 18z GFS ensemble charts for 850mb temps since Eric A. asked for them:






Have a nice weekend, it looks perfect for outdoor work with dry vegetation, partially frozen ground, and no cold east wind!  That’s a rare combination.  Can’t wait to get those chainsaw chaps on and cut something down…

Chief Meteorologist Mark Nelsen

161 Responses to A Very Cold Night Tonight

  1. SnowedIn - North Plains says:

    High of 32.9 here in North Plains today under partly cloudy skies.. Had some good fog this morning though, lots of frost. The ground totally never thawed either. Now down to 32.0.

  2. 18z GFS looks even stronger with the ridge. 850mb temps are at +8c or warmer for 9 consecutive days. That has to be some kind of a record? I’d like to find that out.

    • SnowedIn - North Plains says:

      So this whole “ridge” pattern we are talking about is what would translate into an inversion (like the present one, but stronger), correct? So while 850mb temps would be crazy warm, 950-1000mb temps would be still chilly/foggy, right?

    • Punxsutawney aka HIOPHIL in Hillsboro says:


      Not sure on the record. At least the 18z shows some precipitation returning, though at hour 312 so take that for what it worth.

      Not sure I’ve ever seen a 16 day run in January with 0 precip.like the 12z had.

  3. JJ97222 says:

    Just beautiful outside this is what the doctor ordered heading to the mountain tomorrow to get a ski tan. Great day outside everyone enjoy so much better than 40 degree rain

  4. A couple of day’s ago I posted some pretty wild temps measured on Mary’s Peak during an inversion on Dec 17th 2011.

    Boydo3 rightfully questioned the validity of the station readings. My wife would have too. She was a WX verification specialist in the USAF.

    Here are few other obs from that day courtesy of MesoWest. MP is the outlier but its also the highest elevation station in the Coast Range.

    Mary’s Peak 76
    Green Mountain 70
    Yellowstone Mt. 70
    Long Prarie 70
    Cedar 70
    Gold Beach 70
    Sea Side 69
    Goodwin Peak 69
    Cinnamon 68
    Wanderer’s Peak 67
    Cape Mears 64
    Mt. Hebo 62

  5. Ben T says:

    Come on Magical low pressure system form out of nowhere! To the weather experts, has that ever happened in our area? A storm showing up out of nowhere when it was supposed to be dry for a prolonged period.

  6. paulbeugene says:

    mid level clouds helped keep insolation to a relative minimum this morning…temps in Willamette Valley have been slow to recover…skies clearing tonight…recipe for colder temps…assuming we don’t get fogged in too early

  7. Forecast next 2 weeks: Sunny in mountains, gradually milder into 50’s ++, valleys frosty/foggy lows mid upper 20’s hi 30’s. Precip: zero. NWS personnel may as well put the office on autopilot, go to Hawaii, and get some R+R.

  8. JJ97222 says:

    This is setting up to be just as in years past nice January’s into February then most likely snow in March and rain till July!!!!!!!!

    • Mark says:

      Yeah, another cold, wet late spring into nearly summer – not what I am looking forward too..

    • WEATHERDAN says:

      What planet are you from. Last January we had massive floods in the Willamette Valley. Over 12 inches of rain fell in Salem last January. I’m sick and tired of the whiny bloggers who are always predicting the worst summer ever. You obviously no nothing of meteorology or climatology for that matter. Go back to Mark’s blogs Last January and people were complaing about the weather. And yes some were predicting a cold a rainy summer. When in fact May was warmer and drier than average. June was average with somewhat more rain than normal. Then July through October 11th was almost completely dry and warmer than normal. As Casey Stengel said “You could look it up”

    • dharmabum says:

      LOL! (;{)

    • Austin_east vancouver says:

      chill fool, your the one whining.

  9. Dave South Salem 500' says:

    20 here for our low.

  10. Sifton says:

    Here’s 1; these inversions we get, going from summer/fall & winter/spring, are indicators of changing seasons? Inquisitively discussed last night among slightly inebriated novices….

  11. Thomyee says:

    12z gfs alert

    Pulling same bag of tricks in lalalala land

  12. paulbeugene says:

    ?Andrew had posted on Western blog that EUG has gotten to 19 this morning, making this the 8th consecutive cold season here that it has gotten into teens or colder.

    I looked at the old EUG station data back to the early 20th century, in addition to EUG airport data…the 8 consecutive <20F extreme minimum for cold season streak is the longest ever…..

  13. 22.7 for a low at my house. With those high clouds coming in I think it’s gonna feel ugly cold today.

  14. runrain says:

    23.9° here in Happy Valley. Should be a bit warmer down by the river for my run.

  15. W7ENK says:

    Leveled out at 28F last night with freezing fog. 30F and fog right now with a thin layer of frost on everything. If I can’t get any snow this winter, I suppose that will have to do.

  16. Dave in SW PDX (235') says:

    Currently 28.4°, DP 27°, after an overnight low of 25.6°, my lowest temp this winter season. Unfortunately the only moisture available is freezing fog…

  17. paulbeugene says:

    Got down to 19 at EUG airport last night….betting on 38/18, 41/17, 42/20, 38/25, 37/26, 38/26 for the next 6 days

  18. ocpaul says:

    24.8 at 286′ in Oregon City. Cooler than all the tower temps. Heavy frost almost looks like a dusting of snow.

  19. runrain says:

    Wow. 22 below zero in Lakeview right now! Friend works in a lumber mill there. Says it’s tough to work in. Uh, yeah!

  20. Tyler Mode in Battle Ground says:

    Only got down to 24 last night. Just too many clouds.

  21. JJ97222 says:

    Sun no wind 10 days of dry weather beautiful we can come out of enclosures for awhile perfect

  22. Interesting facts that are fun on a “cold” night: the coldest temperature ever recorded at DLS in nearly 65 years of records was -25 on February 3, 1950. The second coldest season got to -17F, that was Jan. 26-27 in 1957. We dipped to -4F on Feb. 4, 1989 – and the most recent subzero event was Feb. 1-2, 1996. In spite of all this, we’ve NEVER seen temps of 0F or colder after February 4!

    I find it interesting that there’s a big drop-off in the severity of arctic blasts somewhere in early to mid-February, if you look at the daily record lows. Really sudden shift somewhere in the lead-up to Valentine’s Day. That means we really only have one month left to get arctic air, and the first 10-14 days of that month look completely shot!

    I’m going to speculate that tomorrow night is the coldest night of the season for many places including DLS….

  23. SNOW! says:

    What would you predict the chance of us getting any more snow this winter, that would give us at least 3 inches or so?

    • 1% chance Highly unlikely we see any more snow this winter.

    • David B. says:

      Well under 50% but better than 1%. The strong model agreement means most of January can be safely written off at this point, but there’s still the last week of January and most of February to go.

      PSCZ’s 1% is inverse wishcasting, in my opinion. Just because winter’s been a bust so far is not evidence that it will continue to be.

    • It”s a trend and no reason to think that trend will change this winter. Just sayin

    • dharmabum says:

      I agree, as they say the trend is your friend……22 last night at Barton.

  24. bgb41 says:

    1/11/2013 Oregon (All) Temperature Summary

    High:48 at CW5925 Coos Bay( 49 ft) & Port Orford (US(90 ft) & DW1265 Newport(164 ft)
    Low: 38 at Port Orford(0 ft)

    High:6 at HOWARD Mt Howard(8150 ft)
    Low: -17 at CRAZYMAN FLAT (6100 ft )

    Largest Diurnal Change: 41 degrees
    CRAZYMAN FLAT (24/-17 ) (6100 ft )

    Heaviest Rainfall:
    0.51″ at CHARLOTTE RIDGE(1220ft)

  25. 00z ECMWF shows no changes for at least the next 7-10 days, maybe longer…. Perhaps the end of the month or into February we’ll see a renewed chance of Snow/Cold. Winter is NOT over yet.

    • gratefulduck says:

      well.. since I am spending 3 out of the nxt 4 wks in Minneapolis for work I am gonna my taste of the arctic for sure.. of course it is looking bone dry as well there.. what a waste of cold air.. at least it means I should be able to make it home each weekend without much trouble… 🙂

  26. Ian says:

    So you’re saying you hate trees?

  27. JERAT416 says:

    Mark, better cut it down before they ban cutting down trees without a permit anywhere in the state! Anyone getting ready to walk to the edge yet…..?

  28. Marcus says:

    It’s snowing……………. Just Kidding, Sorry really bored!

  29. Tyler Mode in Battle Ground says:

    26 here

  30. DCZ (Hillsboro) says:

    So this morning in Hillsboro we had wet streets, some black ice and, of course, no snow. Except for one area. As I passed Intel there was white stuff on the ground. In the past the same thing has happened and someone referred to it as “the Intel effect.” Because whenever we are borderline for snow, you will see some/more within about 1/2 mile of Intel.
    Has anyone heard of this? Is it real? Does Intel in effect create it’s own clouds?

    • Tyler Mode in Battle Ground says:

      Yes it’s called iSnow. Some AMS members are looking into a presentation on it:)

    • jplayer1234 says:

      I don’t think it’s intel. But I know what you’re talking about. Most by the intersection of evergreen and brookwood. I think it’s a manufacturing plant there and not intel that is the cause. I think the plant puts out some steam that freezes. It’s not really snow, but a thick layer of frost.

    • DCZ (Hillsboro) says:

      Yeah, I think you’re right. I don’t know if I’ve ever seen anything actually “fall.” Seems like I have, but maybe not. Maybe it just “settles” to the ground over there. Neat, thanks for the reply!

  31. swift says:

    Imagine if the system that the NAM had two days ago verified, would have been a pretty good snowstorm for the valleys with it being so COLD. But you know how it goes right, its too warm when we have moisture but as soon as we get COLD, moisture is nowhere to be found. See you all next winter, this winter is OVER!

  32. Currently 26.1 at my place. My weather station:


    I bet I see 19 tonight, as long as the fog holds off.

  33. W7ENK says:

    So far this season PDX has dropped to 23;

    Literally as I read that, KATU Dave said the coldest temperature of the winter so far was 29 on December something-th. Just now as I was typing that out, he followed it up during his 7-day again saying “Tonight we’ll tie this winter’s low with 29…”

    Whooza whuuuh??? o_O

    My temperature here dropped like a rock last hour from 35F at 5pm to 28F at 6pm, DP 27F, and my grass is all crunchy! 🙂

    • Greg Carstens says:

      I still have some left over snow from last night in the shaded areas of the yard. Yes the ground feels like an iceberg to say the least. The high made it to 36 yesterday here and the low this morning was 23. There was a enough snow from the convergence zone remnants to whiten the grass really good but it didn’t cover it all surely. Some snow on the bark areas of the garden as well. Nothing more than a trace here in the log book. It will be interesting to see if I make it to the teens tonight.

    • JohnD says:

      ‘Not sure what to make of the current weather pattern. 28.0’ at the moment here in inner swpdx b-t-w. 14 ensuing days of zero precip inversionary cool/cold weather also translates to a 14 day erosion of the theoretical low elevation winter weather window. A rotten shame that the earlier low pressure system didn’t materialize. Otherwise we did, indeed, have a bonafide Portland “event” in the making. A real shame. I am a born/raised w. Oregonian so I do “get it”. My wife’s family is from Boston-where they believe God created weather-and they have a tough time understanding ours. Insult to injury. Anyway, here’s hoping for the quintessential retrograde (that may never come.) There is still time–but things better hurry up! Most of we w. Oregon geeks are realists and don’t demand much. But I’ll tell you what, even that 2″ snowfall that lasts but a day has been really, really tough to come by in recent years. ‘Hope the city’s 55 snow plows haven’t rusted out yet!

  34. Hal in Aims says:

    wonder what happened to my post about temp and melting around 2:50 this afternoon??

  35. Rusty (165th Beaverton 259') says:

    Temp reads 29 and the deck is frozen. Chilly night ahead.

  36. Greg Carstens says:

    WOW Mark, that is one BIG ridge on the ensemble charts. Hoh Hum, I would rather have the active weather back than a boring regime around here but at the same time it can be quite useful in the afternoons around here in Southeast Tacoma.

    This morning was sure interesting though dropping down to 23 degrees and getting a dusting of snow overnight. It made for a pretty icy morning for sure around here. I am glad I did not have to be in it driving early on.

  37. ocpaul says:

    “it looks perfect for outdoor work…” would mean I was moving snow out of the way to get my truck out of the pole barn.

  38. pappoose in scappoose says:

    I’m getting the chainsaw chaps on as well. Still have two blow down trees to cut up. And lotsa slash to burn…if a burn ban doesn’t start up (probably will).

    • Lurkyloo says:

      That’s very manly man stuff ‘poose! 😉

    • alohabb says:

      Wait until daylight..it would be easier. Unless you like wearing the chaps around?

    • pappoose in scappoose says:

      I really like a bonfire in the dark! (zombie danger though)

    • Lurkyloo says:

      Chainsaw chaps, wood-cuttin’, and bonfires … I don’t know if we should call you “‘Poose” anymore. Maybe Pa? Pappy? I’m just curious …
      do you morph into something else when the weather gets real cold?

  39. Longview - 400 ft says:

    Currently 31.3
    I am thinking upper teens here as well.

  40. Jordan (Raleigh Hills, 420') says:

    Already down to 31F here. Its going to get COLD… a few could later though, IR satellite is showing a good stack clouds coming in from the northwest

  41. alohabb says:

    30 now in Aloha. Bet we hit the teens here!

  42. bgb41 says:

    Already 29 degrees at 5pm here at Battle Ground Lake. Surely going to drop to around 20 tonight in parts of Clark County.

    • Greg Carstens says:

      28 in Southeast Tacoma at 6:28 PM. Almost forgot to thaw the rain gauge out so I could get a precip measurement for today. Out of the 0.07 inches of precip I measured I did manage a trace of snow. The snowboard near the gauge was not fully covered. Nothing more than scattered snowflakes on it so I could not even measure at least 0.1 inches of snow with the snow ruler I have…Kind of lame..lol

    • Greg Carstens says:

      I wonder if I might make it to the teens also tonight since my low this morning did make it down to 23.

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