Freezing Rain Update: Looks A Bit Less Likely

9pm Wednesday…

I think it’s very unlikely we see anything other than a spot or two of ice in a valley out near the Coast Range late tomorrow morning.  The chance for a metro-wide glazing of ice?  About 10%

Look at the high temps for today; warmest in 8 days here in Portland:


You can see where the mild east wind cut through the middle of the metro area (at least above the surface) and helped to clear the fog out.  Anywhere north or south of us stayed near or below freezing.

This doesn’t affect tomorrow’s weather at all because now with the clear sky temps have dropped below freezing again; back to the usual freezing fog programming overnight and tomorrow morning.

I don’t have any new thoughts on tomorrow’s chance for freezing rain west of the Cascades, EXCEPT that this evening’s models are slightly slower with the rain tomorrow.  That’s very good news if you don’t want ice on roads.  Our RPM precip forecast at 11am shows the edge of rain just coming down off the Coast Range into the farthest western portions of the metro area:


and by 1pm it has spread to about Camas/Gresham.


The 00z WRF-GFS is even slower, holding off precip for most of us by 1pm.  I’ve never seen freezing rain start DURING THE DAY (after 9am) unless the temperature is real cold…like 25 or so.  Not happening this time around.

One more thing…

Air temperature doesn’t equal road surface temperature.  Even on a cloudy winter day the road surface is going to be warmer than the air temp, often significantly warmer.   Take a look at the Rocky Pt. ODOT sensor along Highway 30 in the fog and clouds today.

At 5am, air temp=27, road temp=28.

9am, air temp=28, road=33

11am, air temp=30, road=39

In this case cold rain might lower the road temp a notch or two, but today you wouldn’t have seen freezing rain glazing over the road after 8am or so.  At the Enchanted Way sensor south of Salem along I-5 it was 28 at 11am and the road temp was 37.   Same thing.

As a result, I don’t believe we’ll have anything other than a spot or two of ice in a valley out near the Coast Range tomorrow morning.

Chief Meteorologist Mark Nelsen


59 Responses to Freezing Rain Update: Looks A Bit Less Likely

  1. Ryan says:

    I hope Rob is OK! Seriously. I miss the anticipation of his model analysis. Would love to hear his outlook on next week.

    • Aloha Rainshadow says:

      Rob is fine, he’s been posting on his FB group this morning.

      • Ryan says:

        Damn I guess he gave up on this blog. Bummer. I despise facebook, so will not be joining that group unfortunately

    • Aloha Rainshadow says:

      He didn’t give up on the blog, I think he is just concentrating on building his facebook group. He’ll be back around.

    • Aloha Rainshadow says:

      Unfortunately not, I’m at work and don’t have access to FB on my work comp, it just pops up on my phone that Rob has posted in FB.

  2. Aloha Rainshadow says:

    Precip on the North coast is WAY WAY ahead of schedule, could get very very interesting on the westside.

  3. Sandi (Wilsonville) says:

    Lightly snowing in Wilsonville.

  4. Ryan says:

    Where’s this south wind everyone was talking about starting before the rain? Calm as can be out there and 24 degrees. Clouds covering the sun now as well, which will limit warming.

  5. Jesse-Stevenson says:

    “Mild east wind” kept us pretty cold out here yesterday. High of 36. 26 this morning with radar echoes already crossing the coast range. Ooops…

  6. paulbeugene says:

    Cold air in south valley, as cold as it is, is very shallow. Had a temp spike up almost 10 degrees in the hour prior to 6am before temp went down, now trending back up. This tells me that winds should have no problem mixing out the cold air this morning.

    Cold snap is over. It was nice having you visit us in the past two weeks. Thanks for the snow. Wish you would have given more to the neighbors up north.

    I hear your evil cousin, fakecold, will be paying a visit next week. Sounds like he has high temps in the 38-44 range in store for us with lows well into the 20s.

    Sounds like the debt collectors will come a-calling to Skibowl. Pattern evolution suggestive of prolonged dry spell, lasting through Christmas. Moodys has downgraded Skibowl to DD-. Timberline C+. Would upgrade to B and hold/buy if they reopen Palmer.

    Congratulations Eugene. You got the best of the cold snap, now you will be rewarded with all time driest year. Bravo.

  7. Andrew (Beaverton, OR) says:

    Looks like its still holding strong in the low-mid 20’s in the west metro and precip is approaching the coastline now…..

  8. Austin-East Vancouver says:

    Its snowing at Hillsboro, only thanks to the Intel affect tho lol

  9. alohabb says:

    Freezing fog is so dense im Hillsboro that it looks like light snow is falling. Crazy!

  10. chiefWright (Marquam) says:

    Interesting quip in today’s AFD at 0550:


    But since then there’s been no verification of any stations in the valley breaking out of the low 20’s.

    It got a lot colder last night than forecast. And there’s not much stratification in the KPTV tower temps this morning, though they’re all near or slightly above freezing.

    And radar is showing pretty decent echos just off the coast headed due east.

    But I notice the valley dewpoints are also quite a bit lower than forecast. If that carries into the mid atmosphere, I suspect it’s going to be a battle between incoming moisture and the dry sponge. But if moisture wins and if any low stratus hangs on to hold down the surface temp:


  11. Mark says:

    No time for detail at the moment, but suffice to say, the models giveth and taketh away. Cool rain looks to be our long term future with lots of much needed mountain snow.

  12. Kenny says:

    The new 06z GFS brings a arctic air plus moisture to a snowstorm at PDX starting overnight Thursday to Friday morning. 850 temps bottom out at -13C at KTTD.

  13. Muxpux (Castle Rock 175') says:

    Not foggy up here, 30 at the moment, but that wind is howling in the trees from the south.

  14. schmit44 says:

    12/11/2013 Oregon (All) Temperature Summary

    High:65 at QUAIL PRAIRIE LO(3183 ft)
    Low: 46 at FLYNN PRAIRIE(1543 ft) & RED MOUND(1753 ft)

    High:17 at HARL BUTTE(6071 ft) & MORGAN MOUNTAIN(4200 ft)
    Low: -11 at DIMLKE (4726 ft )

    Largest Diurnal Change: 44 degrees
    Horse Ridge (US (40/-4 ) (4160 ft )

  15. Model Rider says:

    Guess we can always hope for retrogression down the road. It happened in ’08 somewhat similar. Dry and no snow up in mountains then bam.

  16. Marcustheweathernut says:

    Mark, are the 00z runs outliners u think ??

  17. Model Rider says:

    Euro is not good. Sorry guys, maybe next time lol

  18. Marcustheweathernut says:

    Still hope?? Kind of …. Lots of uncertainty tho,…

  19. Darlene in Boring says:

    Down to 27 here, according to both thermometers. I think I just saw Mark’s graphic say it was 37 in Sandy. Could there really a 10 degree difference in 5 miles? Sandy is a bit higher in elevation but not that much.

  20. ive often wondered where and how they take these road temps.

    is it an infrared sensor? is it taken on the shoulder? does traffic affect it (like when it snows less traffic=snowier road), etc.

    btw, heres the WA road temp page for SW Washington. theres a sensor at Paradise

  21. Tim G says:

    Mark, can you elaborate on “near the coast range”. What are Yamhill/Carlton/Gastons chances for frz rain?

    • Mark Nelsen says:

      Yes, those are the spots where I think it’s POSSIBLE. That doesn’t mean it’s going to happen, just a better chance there. I would include Sheridan, F. Grove, and Banks in that listing too.

  22. David says:

    What about us down here in Abany where my weather station already has us at 18 at 9 pm? You think there is enough southerly wind and lack of rain to get us to escape the frz rn? It never got above 30 here today with the snow pack still around. 🙂

    • boydo3 N Albany says:

      My sense is that by the time any precip arrives, we’ll be warm enough to get just plain ol rain. I hope!

    • David says:

      I hope. I am done with this snow pack and frigid temps. I am at 16f and feel we will have pockets of ice regardless of the arrival of rain. This is a weak system. Unless it has southerly winds strong enough to scour, then I don’t believe we will totally break out during the day. The most likely scenario will be pockets of roadways protected by the sun that will be treacherous. until afternoon. We have 3 inches or better of ice and snow on the roads that are not traveled much here. This fore cast is spot on but I believe that it will be more dangerous for travelers to be confident in wet roads and then hit the areas that have been frozen for a week.

  23. Ryan says:

    Boo! Back to boring 40’s and rain I guess. Let me know when winter comes back.

  24. Marcustheweathernut says:


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