12z GFS Ensemble Chart


For regular folks, read the previous post below, this is just to talk about a chart with a whole bunch of lines.

The 12z GFS is in and it looks exactly like last night’s 00z ECMWF showing a cold trough dropping over us next Monday night & Tuesday.  Possibly cold enough for a dusting of snow all the way to sea level if everything works out right, but it’s a real marginal setup with most energy/precip heading farther south from Eugene into N. California.  Tuesday could be a snowy drive down I-5 in SW Oregon and into the Siskiyous.

Then there are still hints that we’ll be close to snow again around Mon-Tues the 25th/26th (I know, 13 days away).  Although the 12z GFS appears to be one of the coldest members of the ensemble, there are others cold too.  Interesting feature to watch…since there is nothing else to do during 3 days of gloom and mild temps anyway:


1:30pm…here is the 12z ECMWF ensemble chart:


2pm…and this is interesting, the 360 hour ensemble maps (about Day 15) from the GFS, 00z GEM, and ECMWF models.  All very similar at the very end of the month with the average ridge position slightly farther offshore.  That allows colder troughs to come much closer to the west coast.  How close remains to be seen, but you can see why there would be such variation in the ensembles above depending on the ridge position.


58 Responses to 12z GFS Ensemble Chart

  1. W7ENK says:

    00z Euro at Hr 168 (Day 7): Close, but no cigar.

    500mb heights

    Down to 522dm, we need sub-520, especially this time of year.

    850mb temperature

    –5C, maybe –6C at best, we need solid below –8C, especially this time of year.

    Per this, no snow, but…

    Look at all that cold air in Alaska at Hr 216 (Day 9)

    Might it move this way?

    2/24. Book it.

    I think the new 12z Euro suite comes out in an hour or so?

    • W7ENK says:

      But look at that dump of winter into the Upper Midwest and headed for the East Coast again! What is that, winter blast number 4 for them in the last month? Lucky bastages…

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

    The last few runs of the GFS have trended slightly warmer for the Monday night/Tuesday system, and show the low staying further offshore as it drops down the coast. Not the best setup for snow in the lowlands, unfortunately.

    • Mark says:

      Indeed, the GFS runs are trending warmer, albeit with some crazy cold la-la-land ensembles towards the end of the run… Let’s hope those outliers drag reality their direction.

    • Mark Nelsen says:

      Yeah, a bit too warm over the next week for low elevation snow. 850mb temps stay warmer than -6 later Monday and Tuesday and now quite a bit of splitting showing up with that Tuesday trough. That’s why we’ve kept a snowflake out of the 7 Day Forecast for now.

    • Ben T says:

      What about the ECMWF?

    • W7ENK says:


      February 24th. If it’s going to happen, it’ll happen then.

      Just watch.

  3. Ben T says:

    Any interesting updates?

  4. bgb41 says:

    2/12/2013 Oregon (All) Temperature Summary

    High:62 at BROOKINGS( 79 ft)
    Low: 48 at Florence Municip(52 ft) & Tillamook Airpor(36 ft) & NEWPRT Cape Foul(1024 ft) & PACCTY-2 Pacific(28 ft)

    High:29 at HOWARD Mt Howard(8150 ft) & CW7477 Lostine(7002 ft)
    Low: 10 at CRAZYMAN FLAT (6100 ft )

    Largest Diurnal Change: 35 degrees
    CRAZYMAN FLAT (45/10 ) (6100 ft )

    Heaviest Rainfall:
    0.96″ at CEDAR(2220ft)
    0.80″ at MEARES Cape Mear(1421ft)

  5. karlbonner1982 says:

    Let’s hear Mark’s opinion on the new 00z GFS’s two most interesting ensemble members:

    1. What kind of high temps do you think would come from a sunny 850mb temp of +10 the last couple days of February? (Assume light easterly flow.)

    2. What kind of high/low temps from a mostly sunny 850mb temp of -12 in the first couple days of March?

  6. Sifton says:

    Mark if your a betting man should I go all in with that beautiful 1 day Friday coming up, or is it more of a moral boosting forecast for us sun starved pale skinned people?

  7. Sifton says:

    This will at least be good for a Portland snow panic, ALWAYS a good laugh!! ‘Trace’ amounts to nothing IMHO……..

    • germantownsummit1000' says:

      Drivers in Portland could see the words: “trace of snow expected…” on a bill board and it would cause them to lose control…

      …of their cars, that is…

      …many of them have already chained themselves up…

      … those folks are mostly in the Pearl…

    • Mark Nelsen says:

      No, only the newspeople freak out, not regular people.

    • dothgrin says:

      Bread…and milk! Bread…and milk!

    • germantownsummit1000' says:

      Mark, I’m not sure to which “regular people” you refer, but not many of them live around me. It’s odd that folks who seem least able to cope with a little frozen precip seem to live in the areas most prone (“prone” is such a strong word around these parts) to getting it.

      (see: Forest Heights)

      …and, for the record, I’ve lived up here since before there WAS a Forest Heights.

      Bring it on…

  8. germantownsummit1000' says:

    I predict 2+” up here Tuesday AM.

    At least I hope for that…

    Maybe I’ll see some…

    I could happen…

    …couldn’t it?

  9. Amy Raulerson says:

    Please let it snow on Monday! I want a white birthday!! I’ll even settle for snow in the air!!

  10. SNOW! says:

    Mark, how likely is it do you think for us to get at least 3 inches of snow on the ground before march 21st? How likely is it looking we will get snow next week?

  11. oldwxwatcher says:

    This will probably bring on some more snow envy. It’s a timelapse taken by a photographer in Hartfort CT. Watch the hands on the clock spin and note that the marks on the yardstick are at one-foot intervals.

    [video src="http://wfsb.videodownload.worldnow.com/WFSB_20130209125023800AA.mp4" /]

  12. pappoose in scappoose says:

    National Weather Service Portland or
    234 PM PST Tuesday Feb 12 2013

    As the upper trough dives south and east late Sat…a period of
    upper ridging may dry things out for Sunday and early Monday.
    However…another more significant system looks likely to approach
    the Pacific northwest late Monday into Tuesday. The current model track of this system brings a surface low onshore near the or/Washington border…with a very cold airmass moving into the region. Based on model 1000 to 500 mb thicknesses and 850 mb temperatures…it appears that snow levels will drop
    well down into the Cascade foothills and Coast Range. Model
    agreement is actually quite good on this system given how far out it
    in the extended it is. Will need to monitor closely over the next
    few days due to lower elevation snow potential. Pyle

  13. Brian Delaurenti says:

    I know everyone on here tends to error on the side of caution in regards to low-elevation winter precipitation, however, I have a good feeling about these maps. If nothing else, a little hope can’t hurt!

  14. Mark Nelsen says:

    I just added the 12z ECMWF chart onto the post, hit REFRESH

  15. Still cloudy up here, but it’s not drizzling or raining which is nice.

    The clouds are brighter though.

    Somewhat balmy too, 48 degrees.

  16. germantownsummit1000' says:

    Mostly sunny?!? up here for the last hour or so – pretty nice surprise considering the NWS forecast this AM.

    49.3 – almost balmy in the sun.

  17. W7ENK says:

    Thanks again, Mark! 🙂

  18. Mark says:

    At this point, the best straws we can grasp at – for those metro area folk – are snowflakes in the air, bark-dust getting covered events. Unfortunately, these troughs forecast are coming out of the Gulf of Alaska, with no easterly arctic air supporting.

    It is very difficult to reach even 30 degrees or less near the valley floor during these events.

    But if this is all we’ve got left, let’s take it and hope for a late-February miracle!

    • pappoose in scappoose says:

      Nah, all we need is enough of a ridge behind the low, cold enough air pouring in from the Great White North, short over water trajectory = Winter Wonderland! Hahaah! (heading out for some dark bark-dust)

    • Marcus says:

      I agree and with the troughs coming down from Alaska we get that dreaded southerly flow on the surface:/

    • pappoose in scappoose says:

      If the low’s dropping down the coast, the south wind will shut off about the time it gets off our coast. The bigger potential problem, is too much over water travel, and all the moisture heading south/offshore of us (as per Mark’s post).

    • Lurkyloo says:

      ‘Poose, does snow not stick to gravelly plains?

    • pappoose in scappoose says:

      It does stick quite well to my rock garden (constructed with rocks off the Gravelly Plains). Dark bark-dust is better though! Hahaah!

    • Sapo says:

      Yes, hope for the miracle indeed. But if you remember last march, I got about an inch or two for snow then, so I wouldn’t go so far as to say “grasping at straws” for a dusting, but yes, winter does seem to be coming to a close.

  19. Ben T says:

    We are going to get snow.

  20. gidrons says:

    You in

  21. pappoose in scappoose says:

    Who’s on first?

%d bloggers like this: