Last Night’s Storm; An Analysis

A strange thing happened today…my coworkers kept saying “good job!”, or “you guys really nailed that storm!”.

Hmmm, now I’ve mentioned in the past that I feel I get a bit to emotionally wrapped up into these events, and this time I felt like in the end I really missed it.  So why the disparity between how I felt I did and what others thought?

1. In my mind, and alluded to in this blog yesterday, I really thought we’d only get very brief light accumulations for the bulk of the metro area.  Of course I had 1-3″ in the forecast during the 6pm show yesterday (so did Steph).  So technically the actual forecast (that 50,000 tv viewers and online viewers at that time saw) was far more than I really thought we would get.  A large part of the metro area DID get a total in that range.  I updated the totals up above.  At least all of the west metro, south, and much of inner east/southeast metro.  And it did not snow south of Wilsonville which was a perfect forecast for all of you in Salem/Woodburn etc…

2. This is the main point:   I, and probably many of you, focused on “how much snow was coming”.  That’s what weather geeks do.  And if it was a snowstorm that was coming for the day (to play in) most other people do as well.  Apparently most of our viewers, and just about everyone I work with seemed to focus on “snow overnight, then a quick warmup with no major issues for the morning commute“.  That’s exactly what happened, most areas transitioned to rain quickly after 1-2am, and the heavy rain melted enough of the snow to avoid a mess.  I didn’t realize that many of my co-workers were thinking we might be totally wrong and it would be 30 degrees and heavy snow at 8am. 

So what went right?  The Winners:

  1. Timing in general, it happened a little faster than I expected, rain to snow, then back to rain.  But models did very well.
  2. Mesoscale models clearly showed a changeover to snow as a distinct possibility, they are getting better and better!
  3. Heaviest totals to the north and west of the metro area.  Lots of 12-15″ totals above Scappoose, Vernonia, Amboy etc…
  4. No snow south of southern metro area.  1/2″ at Sherwood is the farthest south I saw.  None in Wilsonville/Canby.
  5. Quick warmup with south wind today.  I remember seeing a comment on here a day or two ago thinking that 50 was way too warm of a forecast for today.  It hit at least 53 at PDX.
  6. Positioning of the surface low…great job most models!  Came inland between Astoria and Hoquiam.  The NAM was a little far south, and several days out the GFS/ECMWF/GEM were better than the much farther south NAM.
  7. Heavy snow (10″+) in the right places as mentioned before, plus the 12-18″ in the Hood River Valley was a nice verification to see.
  8. This blog…no drama or major issues as we’ve often see in the past.

What went wrong?

  1. More snow than expected eastern metro and Clark County.  3-5″ east of I-205 was more than expected.  I didn’t expect the 3-5″ totals in east Vancouver, Camas, and Hazel Dell areas.  As mentioned earlier though, maybe much of the public didn’t care since it was late at night and melting quickly by daybreak.
  2. Me saying “my gut feeling is we get very little snow” on the evening broadcast.  Should have just kept my mouth closed and the forecast would have basically been okay.

So I’d rank it a 30% bust, but 70% fine forecast.  Feel free to disagree in the comments, you know I’m not easily offended.

By the way, has anyone noticed the very cold arctic air creeping farther south than any model shows into north central and northeast Oregon this evening???  More on that and how it affects the Gorge forecast on a post later this evening.

Chief Meteorologist Mark Nelsen

149 Responses to Last Night’s Storm; An Analysis

  1. W7ENK says:


    Glad I’ve got a front row seat along the Downtown Portland waterfront! The river looks normal at the moment, FWIW.

    I may gave to take my camera around and get some B-roll shots of Johnson Creek after work!

  2. Jeremy KF7NGT says:

    North Salem High School Flooding.

    • Jeremy KF7NGT says:

      Locker rooms flooded with sewage, restroom facilities closed, 2000 kids and the school is still open!?

  3. WEATHERDAN says:

    Many roads are flooded here in Salem. Mill creek is in flood stage now. The NWS Hydrological Center is now forecasting the Willamette river in Salem to hit at least 31 feet. 28 feet is flood stage, 32 is major flood stage. So many roads are flooded here right night now you have to take a lot of detours to get around. We have had 7-8 inches of rain in Salem since Tuesday. The problem is that they are forecasting many inches of rain over the next week or so. If this comes to pass the flood down here will be the worst since at least 1964.. Right now based just on river levels this is the 4th worst flood since 1964. This is getting serious folks.

    • you are absolutely correct weatherdan! very serious situation.

    • After tomorrow’s storm we can expect the Willamette to crest over the weekend. Doubt it will get nearly as high as ’96 for a couple reasons.
      1. In 96 we started with higher river flows before the rains began.
      2. The freezing levels went up more dramatically and up to around 8K.
      3. The snowpack was deeper.
      4. It rained non-stop for four days. We will get a break later today.
      5. The rainfall seems to be more concentrated this time (the central part of the state).
      But this time the smaller streams seem to have reacted more quickly (in our area). And it ain’t over yet! Also there is more wind this time, which could have a greater impact on travel.

  4. Jeremy KF7NGT says:

    Salem Flood! Like 1996!

  5. Jethro (Canby ~187') says:

    Waits for Mark’s “flood” post now… wow, what a week!

  6. Roman~Snow-Zone-Monmouth, Elv. 223' says:

    The rain has finally ceased. Lots of flooding… Just imagine if this all fell as snow. We would have like 6+ feet!

  7. I am hearing so much about Salem/Turner….anyone know about Vernonia? They got a lot of snow up there.

  8. PDX Weather Nut says:

    We really needed the rain but this is too much too fast, lots of local flooding and melting mountain snow.

    I wish in the future that the NWS would focus less on “erring on the side of caution” and more on making an accurate forecast.

  9. Rob in Aloha says:

    Wow it’s kinda wet out today!

  10. muxpux (Castle Rock, WA 175') says:

    33.5 and pouring rain here. 😦

  11. W7ENK says:

    Oops, bot caught by the filter… too many links, I forgot.




  12. W7ENK says:






  13. El Donut says:

    A spring has just appeared in my NE PDX basement. First time for that. Water table must be way, way up.

  14. Jory (Sandy) says:

    Looks like TWC’s Jim Cantore presence is bad luck. Large parts of the NW are getting slammed with weather woes. Tons of ice in Seattle, further North it is COLD. Further South it is warmer, but absolutely soaking wet.

    But look on the bright side… Lala land is trying to give us some real winter lovin’.

  15. Kyle says:

    Salem is gusting into the 30s even though the forecast said S winds 5-10 mph. It’s more then twice the forecast now.

    Any chance of a strong burst of south winds?

  16. jakeinthevalley says:

    Well, just talked to my wife at home and our creek is only about one foot from finding a new route through my back yard.

    Looks like we may be seeing a back edge of the heaviest, steady rainfall.

    Over 6.5″ now.

    • Jory (Sandy) says:

      Where are you at Jake?

    • I saw that too…gosh, I hope it is a back edge and we get a break soon. Water is starting to come across the road towards my front yard. The pumps are ready to go but I sure hope I don’t have to use them.

    • jakeinthevalley says:

      West Salem

    • I hear it is really bad down there. Hubby works for ODOT in pdx and said that they evacuating one of their own buildings due to flooding. Hope your property will be ok.

    • jakeinthevalley says:

      The ODOT complex is down off of State St/Airport Rd. It is right on Mill Creek. Historically, that can be a bad place. The only saving grace right now is that the Willamette is not that high yet and Mill creek is draining at a much faster rate than if the Willamette were at 25 feet. It will get there soon enough and cause a back up of the system.

  17. gidrons says:

    Mixed reviews on your Columbia County forecast. From what I hear, St. Helens got a foot. At 1000′ elevation above Scappoose, I got 26 inches.

  18. W7ENK says:

    I’ll bump this up:

    Apparently, the trend has been established, and it is progressing, now inside 6 days? According to the chatter I’m hearing over the 12z, anyway. 😯

    • W7ENK says:

      Gaah! Copy paste brings with it typos…

      inside *8 days.

    • gidrons says:

      yes, 12z looks wet. If I lived in Vernonia, I’d start filling sandbags.

    • David B says:

      And it looks like Deluge will be followed by Arctic Blast, if the model pans out. Hope you guys to the south get something precip-wise if the latter materializes. We’ve had more than our quota of wintry precip in the Puget Sound region this week. Time to let someone else have a chance at it.

  19. PaulB/Eugene says:

    GFS Ensembles showing strong signal for arctic outbreak, this time with negative anomalies digging farther S than with most recent (ongoing in Seattle unfortunately for them) episode.

    Canadian ensembles and Euro Ensembles trending toward ridge farther W, favoring instead a deep trough in NE G of AK with wet pattern/snowy in mts (looking out to 240h).

    Michelob model not running yet.

    Have to wait and see..was worth at least a comment this morning. Atmospheric river events sometimes are precursors to arctic events in PacNW.

    • PaulB/Eugene says:

      This is in day 11-15 period.

    • Thanks Paul. What is the flooding situation down there like. Really getting ugly up here. What a tragedy in Albany last night.

    • Jory (Sandy) says:

      Alright, I’ll show my ignorance… which model is the Michelob model?

    • Dave in South Salem (500') says:

      The model is obviously nuts it shows record cold hitting then.

    • David B says:

      @Dave: The models often seem to overdo the cold when they forecast an arctic blast. Even if the blast materializes, no way is it going to get as cold as that chart says at the surface.

    • Brian in Bellingham says:

      The 12Z Euro has the high pressure east of where it did last night, right about 150W, which is the sweet spot. I think a big improvement from last nights run.

    • Sandman - Aloha 300' says:

      Paul I concurr the tropical jet stirrs things up and does seem to be a precursor to an arctic outbreak in Oregon. I also don’t discount record low temps. They have to happen sometime. 😀

  20. pappoose in scappoose says:

    Cliff Mass on the Ice Storm to our North:

  21. jakeinthevalley says:

    Well….just broke the 6″ mark for rainfall in west Salem over the last 60 hours. The creek is threatening my lower deck this morning. Never thought it could get this high. I am just a plugged culvert away from something not so enjoyable.

    • Our rainfall rates are on par with the 96 flood. I’ve had 4.2 inches in the last 30 hours.

    • W7ENK says:

      I was just thinking the same thing, boydo.

      We’ve had an ungodly amount of rain over the past 3 days. This is shaping up a repeat of February 1996. Some areas South of Portland have seen upwards of 5-6 inches of rain since Tuesday. All the low elevation snow up to ~5000 ft is melting rapidly. If this doesn’t let up, seeing the Willamette jump the seawall along the downtown waterfront in Portland is not outside the realm of possibilities.

      Let’s hope this rain lets up soon!

    • W7ENK says:

      That, and once all that snow starts to melt up North, I’d imagine I-5 will be going under 14 feet of water in the Centralia valley again. That’s three times in 5 years? So much for 100-year floods, seems they’re becoming the norm.

  22. Ryan (Walnut Grove) says:

    I think the most important lesson from this little snowstorm is that the NAM is a little too extreme with these events. The GFS & EURO as usual ruled the day with the forecasting.

  23. David B says:

    It’s still going… It keeps going and going and going…

    Our winter storm in Seattle, that is. After a pause in the action late last night, I awoke to sleet clattering against the window. More freezing precipitation is falling, and we’re now under an ice storm warning for up to .4 inches of freezing rain. SeaTac Airport has been struggling to stay open and was shut down entirely for a few hours this morning.

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