Much Drier Forecast

Elongated surface low appears to be just about right over the Coastline at 7:30pm…kind of hard to find on the satellite picture, but the buoy just off of Astoria has gusty north wind now, so it’s on the land side of that.

As the low moves inland we should all (Coast to Central Oregon) see a good burst of west or northwest wind by daylight at the latest, more likely around midnight in the metro area.  Then temps drop quickly with a much cooler airmass filling in behind.  Showers last until just after daybreak and then that should be it.  Most likely the metro area will be mainly dry after 8am according to our model here and the UW-MM5.  Just leftover showers over the west slopes of the Cascades after that.  Cross-sections and other model info seem to keep sticking snow above 1,500′ late tonight and in the morning, so I doubt anyone in the metro area will see snow.

GFS & ECMWF are definitely heading towards splitting/ridging in the 7-10 day period.  Models (especially GFS) tend to try and send weak systems through the ridge too easily, so I’ve taken rain out of the forecast.  Looks like late Friday/Saturday morning and New Year’s Day may be close, but I’m betting we’ll stay dry.  Lots of east wind and cool temperatures the next week as well, especially since we lock in cool air at the surface that moves in tomorrow east of the Cascades…Mark

168 Responses to Much Drier Forecast

  1. Andrew---Ellensburg, Wa and Portrland, Or says:

    heh rob, i like the new name.

  2. AtmosphericWrath -Southeast Portland- says:

    Derek, I feel that you did a pretty good job. I was closely mirroring your thoughts, but was not quite as confident. Appears to me that as the backside of the low and accompanying deformation band weakened to the point the air not only didn’t get cold enough, but not enough heavy precip to do much with it anyhow.
    It figures that up north they yet again got the maximum effect of this situation.
    My next thought….
    Appears we are in for a fairly prolonged period of E winds blasting through the Gorge (Again, especially E of I-205).
    As times goes on the air will become much drier/cooler as the high pressure settles firmly into the Columbia Basin.
    After 3-4 days of this the Gorge begins to slightly cool down. Dewpoints should be in the upper 10’s to low 20’s.
    This sets us up for a potential transition event IMO.
    Any thoughts?

  3. Derek-West Gresham- says:

    Well I do see that Jacob, but I dont want another disappointment. Even if there was some snow last night I was asleep, my Dad saw it. lol

  4. jacob BPA says:

    Meeting today
    Weather pattern seems to be trying to change we have seen this a couple of times this year where there seems be the want of a Ridgy or Splitting of systems the last few times it has been weak then its back to Stormy weather
    so have gone with a lull in the weather the next 3-5 days then back to the norm
    Cold air and I mean Very cold air is Going to Be in place in parts of N Alaska and The yukon VERY COLD
    will try to Push South Between Days 5-10 and Take a hold in the North of the yukon and Alaska will have to watch
    this closely as this

  5. Derek-West Gresham- says:

    The only chance this week would be some ZR, definitly not enough cold air in the basin for that though so I would say just cool and windy for a long time. January doesn’t look good right now, signs are getting worse I think.

  6. Derek-West Gresham- says:

    Well I was born and raised here. I have only intently read models for a little over a year so I am still learning things. So thats why I mess up sometimes.
    My strengths
    Snow, wind, thunderstorms
    ZR, lingering showers, fog

  7. jacob BPA says:

    Derrick Has plenty of knowledge and is Gaining He has done a Stint with Mark
    and is now a intern at Katu
    Ive Been around weather alot and Work with the weather alot and Been to College for Weather related topics LOL
    and Derrick For being in High School has a great start on what
    could be a very nice Future in the Met Dept
    I sometimes compare some of our Forecasts with derricks and our peeps have almost 40years Experience as Mets and Derrick Does a good job

  8. Andrew---Ellensburg, Wa and Portrland, Or says:

    Maybe the 1st? But thats just wishful thinking on my part. Some models do want to bring in a little something, although it would be a small event. Most likely going to get taken off the models in the next few runs.

  9. Jerry says:

    no where in sight as of this time Kristen

  10. Kristan - Tigard says:

    Well, since nothing came of this event….when is our next “chance” for snow?

  11. Promet says:

    Derek…fair enough. If I may ask…what is your background? I read quite a few posts from you and Rob but don’t have a feel for your background.

  12. Derek-West Gresham- says:

    Thanks for the support. I don’t want to give the perception that I am really mean or anything but I get tired of being treated like I know nothing and am wrong all the time. Well, I will leave that opinion to the readers. Thanks again

  13. Andrew---Ellensburg, Wa and Portrland, Or says:

    In my opinion, Derek forcasted this storm better than most of the people who posted on this blog. The NWS never once mentioned snow for portland to seattle. But areas around seattle got several inches of “surprise” snow. There was accumulating snow here in Oregon lower than most the mets forcasted. And Derek forcasted this out several days ago, before any met even had snow levels below 2500 feet. And for the record i did get snow last night and i am in the metro area. And yes it stuck, even though it was very short lived.

  14. tracy (yamhill county) says:

    I love reading this blog and learning new things about how the weather works. Derek as far as I can see you have been close to correct most of the time and I have to say, since snow DID fall you were closer than those saying it wasn’t going to at all. I follow you and Robs forcasts as close as I do Mark Nelsons. Please don’t let the critics and pot stirr’s discourage you! I look forward to more forcasts.

  15. Derek-West Gresham- says:


  16. Derek-West Gresham- says:

    Ben it snowed are briefly stuck at my house, snow fell and didnt stick in a lot of other places. You were WRONG ben. Promet, this is who I am talking about…later guys.

  17. Derek-West Gresham- says:

    1. If there is no cold air in place/through gorge SEA needs to be 32 or lower before we can get any significant snow to fall.
    By this I mean at that temp PDX would fall to 34 or so and would see straight snow. For accumulating snow in the city SEA probably would have to be 28-30 or lower. Anything else I missed? I am willing to learn anything else. You dont seem quite like some of the others so I will cool it.

  18. Ben says:

    Oh my. Are you guys serious?? HA HA HA! Derek c’mon, admit your forecast was once again, BUSTED!!!!

  19. Derek-West Gresham- says:

    If you want to know what I will remember for next time it was…
    1. If there is no cold air in place/through gorge SEA needs to be 32 or lower before we can get any significant snow to fall.
    2. Even with very cold upper levels with strong onshore flow we will stay warm without precip. With precip we will easily fall and recieve snow.
    3. Cold air easily moves into NW washington, not as easily NW oregon
    . (inland regions)

  20. Derek-West Gresham- says:

    It was snowy at times, during the night, had some snow this morning..etc. Promet I have not seen enough of your posts to know if your any good or not but I know what I need to remember for next time, you should too. Thats the end of it, if you have read this blog for any amount of time you will know why I strongly defend myself regardless of who it is but enough..leave it be and I will too.

  21. Derek-West Gresham- says:

    Oh, I know I wasn’t totally right. The reason I “freak out” is because I am tired of getting told I am wrong by people who HAVE NO IDEA WHAT THEY ARE TALKING ABOUT!! Now, I know some of these people have valid reasoning but some people just do it to make me mad. And after listening to it for a couple months a person can’t take it any longer. So if I have to defend my statements I cut out any niceness and just tell it like it is. People dont have to undercut my forecasts, and if they do I am not going to be any nicer. Normally I would but like I told you everybody is saying no snow at all when in fact I did get some, and we were close to getting a lot more.

  22. Promet says:

    Derek…Calm down…no one is picking on you. All you have to say is “I expected more”…”here is what didn’t work out.” Your words yesterday were “snowy at times”. Like I said before, your reasoning was fine. However…your forecast was unrepresentative. You saw the potential that alot of people didn’t see. However…being fair in your assesment of your own forecast leads to credibility.

  23. AKB-tigard says:

    well derek i didnt even get a mix. i only got down to 39.8. i dont think you were wrong but you werent totally right. i just think you freak out to much. dont worry about what other people say. dont comment back to them

  24. Derek-West Gresham- says:

    Not really a nice thing to do but I get hounded all the time for my forecasts. Here is what YOU said. “That being said…we will probably see some wet snowflakes tomorrow morning especially from Vancouver north and in the west hills.”
    Here is yours, you were wrong. Learn from it because I had light snow accumulations, I will learn my mistakes and you should learn yours.

  25. Derek-West Gresham- says:

    I don’t really care if your telling me I am wrong. If you want to hear me say, yes I expected more, but all I was willing to forecast was flakes for everyone and some accumulation for me. Well as far as what I forecasted was correct and neither you or any of the others have any grounds to tell me otherwise because you all said no snow at all.

  26. Promet says:

    Derek…there is a difference between a forecast being correct and being representative. The best forecasters admit when things don’t work out. They own it and learn from it.

  27. salemphil says:

    Looks like most of the showers…or what is left anyway, is being eaten up over the coast range.

  28. Jerry says:

    Tacoma!!! Gosh Seattle/Tacoma has a a GREAT Fall/Winter compared to portland… When shall we get our break!

  29. jacob BPA says:

    tacoma has 3 inches of snow

  30. Andrew---Ellensburg, Wa and Portrland, Or says:

    This morning at 4:00am i had a heavy rain/snow mix band come through up here in the hills. Turned to all snow for about 15 minutes and accumulated very lightly on my back porch and cars. All melted this morning, no sign it had even snowed last night lol.

  31. Kristan - Tigard says:

    It was raining about 10 minutes ago here in Tigard….light rain, and kind of sunny.

  32. Cherie_in_Vernonia says:

    sure is windy here which is unusual

  33. N3EG says:

    >…everybody had some snow fall.
    >Even if you didn’t see it.
    The previous weather statement was brought to you by Invisiweather.

  34. Derek-West Gresham- says:

    Sleet/snow/rain here right now. And everything I guaranteed did happen. I said I would have some sticking, and it was light but occured, and everybody had some snow fall. Even if you didn’t see it. So that was fulfilled. I guess I didnt post my most updated thoughts on here last night.

  35. Promet says:

    Be honest Derek…your forecast wasn’t perfect. Your reasoning was fine but the wraparound fell apart as it moved overhead. The meteorologist on TV weren’t perfect either. The setup had to be perfect to get snow in that pattern. It didn’t work out this time.

  36. salemphil says:

    Hey everyone, just went to get the mail and thought it was sunny outside….well it is but it is also a rain/snow mix outside right now and it isn’t even coming down that hard!

  37. Derek-West Gresham- says:

    Stupid radar died again. ahh! Well there are a few showers around, if we can get even one of those in the metro area watch out for snow. By the way my dad says there was some slush this morning at my house at 5am so my forecast was perfect!

  38. AKB-tigard says:

    o nvm. it looks like the radar sint working at the moment. thats too bad. it looks like it will be a chilly night. its getting windier here. my temp is about 43

  39. AKB-tigard says:

    ya the only problem is most of the heavy showers are to our south west. jsut think if all of thoe showers wre pointed towards us it would bring down alot of cold air. it looks like a light shower will hit the metro area. that will cool us down a few degrees but after that it looks like the moisture will be all gone. o well!

  40. jake says:

    some pretty dry air over us now, evryones dewpoint is down around 32 or so. All we need is 1 HEAVY shower to last about 20 minutes and i bet we’d see soem flakes

  41. Cherie_in_Vernonia says:

    For whatever reason the NWS is saying I might get snow today?? They have flakes on the pic…

  42. Promet says:

    According to the KPTV tower temps some wet flakes may have mixed in at the valley floor at around 3am when the precip was hardest…for what it’s worth.

  43. Derek-West Gresham- says:

    I wonder why we are all in the lower fourties though. Strong onshore flow I know but why colder, and then much warmer. Seems like there are lots of showers around, even one over the metro. If we are lucky, may bring down a little snow.

  44. IceKeeg - Close in SE says:

    Did we actually get much in the way of long lasting heavy precipitation at any point like Seattle did? Judging from a rain gauge at a weather station nearby, the precip really didn’t come down like people (including professional forecasters) seemed to have expected. Given that it *does* seem to be a situation where the heavier precip would drag down the snow level, it may have just been a matter of lack of moisture, as per usual…

  45. Derek-West Gresham- says:

    Nothing now but I am pretty sure there were flakes coming down here at night. From what I hear it snowed down to 500ft and stuck in spots, not a good, nor terribly bad forecast for me. My guess is if you guys were up at 3:30 you might have seen some too lol. I find it odd that Seattle had real snow though.

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