More Action Ahead

Okay, we can move on from the big “ice storm” now.  Looks like in the end it was just a marginal event with almost no evaporational cooling effect in the lowest 2,000′ or so.  I would argue that mesoscale models did great with the mid-upper levels of the atmosphere (above 1,500′), but were horrible in the lowest layers.  Consider that we never did get a southerly wind or for that matter even a drift of south wind today.  Imagine if it would have been 5-8 degrees colder to start…Portland would have been an icy mess all day. 

Moving on…the front on Friday is sure looking less juicy on recent model runs.  Plenty of chilly air behind it Saturday, but snow levels only down around 1,000′ and minimal post-frontal showers.  The weather will just turn chilly, dry, and breezy later Sunday through early Tuesday.

The interesting action is Tuesday and beyond.  There appears to be an epic battle shaping up across the eastern Pacific and western North America.  A converging of the mild and moist westerly Pacific Jet and the very cold northerly jet on the back side of a very strong upper-level high over Alaska.  The interaction of these two will probably make a mess of models for days to come.  We could easily just stay in the mild westerly flow, or see the northerly flow take over…who knows 6 days ahead.  The 00z GFS was similar to the 12z ECMWF with several wet low pressure systems interacting with the cold air starting Tuesday.  BUT, the new 00z ECMWF totally swamps us with the milder southwest flow.  As I said…who knows?  I can remember a bunch of these situations in the 1990s with models flip-flopping around 3 days before the event.  Regardless, the weather action is going to really pick up again after Monday.

Chief Meteorologist Mark Nelsen

563 Responses to More Action Ahead

  1. PaulB/Eugene says:

    At 18Z Thurs Jan 13 Williams Lake BC -28.6C 850mb temps, with 20mb gradient between Williams Lake and Bellingham…that is strong…PDX getting rain however….BLI 850mb temps do not drop below -10C through day 7

    • Rob "Wrath" S.E. Portland says:

      I’m thinking due to east winds PDX sees snow/ZR.. but the dividing line is VERY close.

    • PaulB/Eugene says:

      PDX…with 850mb temps below freezing…it would be snow I guess…not ZR. It would be close. Looking at GEM model…looks like potential for really cold air to come past day7…

    • Rob "Wrath" S.E. Portland says:

      GEM is fantastic indeed. I’m still wondering if models are trying to move the block off too soon. Would be nice to see the ensemble variability spread narrow soon.

  2. Yevpolo1990 says:

    This upcoming wintry event is really making me kinda worried, because of the amount of freezing rain we can get….it is almost scary!
    Remember 0.25 of it is catastrophic.

    • Rob "Wrath" S.E. Portland says:

      .25″ is not catastrophic.. 1-2″ or so would.

    • Yevpolo1990 says:

      well it looks like 0.5 inches is what we are getting

    • Rob "Wrath" S.E. Portland says:

      Define catastrophic to me… that would help me understand.

      To me Catastrophic is = Severe tree damage, widespread power outages, impassible roads. It would take I believe at least .75″ ZR to do that.

    • Yevpolo1990 says:

      Well that is what i meant, i remember weather channel saying 0.5 inches is what makes trees fall down, structural damage, downed power lines and such.

    • I could be completely wrong, but it sounds like something may be lost in translation here – I think one of you is talking about straight up precipitation falling as freezing rain, and the other is talking about ice accumulation from said precipitation.

      Which leads to a question from me – how much ice accumulation could be expected from, say, 0.25 inches of precip falling as freezing rain? Generally speaking…I know several variables would affect this.

    • Yevpolo1990 says:

      I mean precip wise, 0.5 inches of it.

  3. Rob "Wrath" S.E. Portland says:

    00Z EURO early look time. I will post 500mb/850mb images if you’d like?

  4. Rob "Wrath" S.E. Portland says:

    Right now model trend is for us to be cold and snowy or cold and dry.. Base this off the past 00Z, 6Z, 12Z, 18Z GFS runs.. All excellent. Tonight was decent, but marginal. 12Z EURO trended heavily towards the GFS/NAM. Yet remember that was just 1 EURO run that has done so, so you can’t say the EURO is in agreement YET. The Canadian tonight is the coldest run yet, that makes 2 Canadian runs 12Z/00Z trending colder. We REALLY need tonight’s 00Z EURO to run similar to 12Z.

    • PaulO says:

      and it will but I will not be up for it.

      Looking for good news in the am.

    • Mountain Man says:

      Wow, I had a feeling the GEM would be good and I have a feeling the Euro will be decent or at least to close to call too. Also to your earlier point, will be fun to see the 4-6 day pattern evolve onto the higher resolution models over the next two days. My feeling is some snow is coming this week and I am still about 50% on the arctic air in the 8-10 day range. GRF did not change my thinking there.

    • Rob "Wrath" S.E. Portland says:

      To my untrained eyes 00Z EURO compared to 12Z run has Alaskan block same placement, 500mb pattern same.. Core of PV/arctic air moving into BC at day 5.. we’ll see how things progress day 6/7 it may move southwest right towards us.

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