Challenging Snow Forecasts

Quite a tough forecast the next 7 days!  First we have to figure out how low the snow level goes the next 2-3 days and how much falls where, then it’s on to the possibility of more significant snowfall early next week.

You’ve seen my thoughts in the previous post.  Lots of onshore flow and brisk south/southwest wind continues at the lowest elevations through Thursday night.  My gut forecast instinct is that means nothing other than a dusting possible in isolated low elevation spots.  I think our RPM model (and probably the UW NAM model again…it’s a real pain) are too agressive with overnight cooling both tomorrow night and Thursday night.  They both show temps down around freezing even at the lowest elevations both nights.  Sure, that’ll happen in isolated spots (Forest Grove?) if the south wind dies down, but I find that really hard to believe for most of us in the Valleys.  That’s where those models both combine the overnight temps and continuing showers into several inches of snowfall.  So I’m discounting that in my forecast (the previous post).

Drying commences on Friday (especially the GFS, it takes all the moisture south), and that continues through Saturday night.

It seems to me the GFS is trending a bit more towards the ECMWF on the Sunday-Monday system, swinging far more energy offshore before bringing it inland on Monday.  At least that’s the GFS trend the last 3 model runs.  But as we’ve seen in the recent past, (November and again in early January), those small details on the global models have huge effects down here near sea level in the Pacific Northwest where we live in such a borderline snow climate.    The ECMWF (Sun-Mon) is another borderline snow situation, in fact I don’t see any sticking snow in the Valleys Sunday or Sunday evening on that model.  The GFS (as of 00z) is slightly colder and looks a bit better for SOME snow Sunday night or Monday morning, but this could easily just be a “dusting” event again.  Still too far away to know.  I see both models are drier after that time.  Regardless, as of now I don’t see a great setup for a major snowstorm (3″+).  But even that could still change.

Chief Meteorologist Mark Nelsen

419 Responses to Challenging Snow Forecasts

  1. EmzinTigard says:

    new post

  2. Josh "The Snowman" From Everett, WA says:

    From beginning to end the 12z was beautiful all the way through!! Amazing run guys!

    Let’s not get all too worried about a couple models showing low pressure going too far west. These patterns always throw curveballs at us, mainly in the form of surface lows right off the coast.

    Going to be fun!

  3. Jake-(Gresham) says:

    I’m so happy the weather has turned colder. The sunny mild weather was bringing on my Spring allergies really bad, they’re subsiding now. 🙂

    • jackfrost (beaverton) says:

      While I kinda enjoyed the mild weather I gotta second ya on the allergy thing. I’ve had BAD allergies from the end of December till now. I have never had allergies like this in the winter just in early summer and fall.

    • Jake-(Gresham) says:

      Oh yea don’t get me wrong I loved the sun / warmth (helps getting up in the morning) but I just wish we could skip Spring misery and go straight to summer…..when everything gets toasted brown lol!

  4. Bishoy says:

    Well, the Euro is persistent in sending everything too far west. Unfortunately, the GFS seems to be playing catch-up with the Euro, as it followed in the trend of sending the Friday system too far west. Hopefully the 00Z Euro is improved. Even within 3-5 days, I don’t put much stock in the GFS for Sunday/Monday right now.

    • Bob says:

      Wasn’t the GFS that first one to send the epic January snowstorm to far north, then the Euro? This was Mark’s post back then:

      “The ECMWF and GFS diverge slightly after Wednesday. The GFS is slightly farther north with the stronger wave on Thursday, while the new ECMWF brings that one right across northern Oregon too…GFS would change us to freezing rain or maybe just rain, but a second tremendous wave of snow/ice in the Gorge and SW Washington. The ECMWF would give us a massive ice storm and and 2nd wave of snow or ice in the Gorge. What happens beyond Thursday I don’t care about as much since it’s beyond the 7 Day forecast.”

      Seems to me the Euro was playing catch up to the GFS then and this time it will too.

    • Bishoy says:

      Bob, you could be right. And, by the way, I really appreciate your input on this blog. Although you have a very optimistic outlook to things sometimes, you know your stuff pretty well, and make valuable contributions to this blog.

    • Bob says:

      Thanks Bishoy, I have learned alot since coming on this blog.

  5. bgb41 says:

    This was quite localized, look at the KM Mountain Cam on Hwy 4 west of Longview. They normally get hammered in this situation and there is nothing there. Unusual for sure.

  6. RobWaltemate says:

    Getting a few snow flakes mixed into the rain here NE of Long Beach WA. Temp 38.3 and the wind hasn’t switched yet. Looks like the cold front to the North is about 1/2 down Victoria Island?

  7. Bob says:

    12z GEM looks incredible, so far GFS and GEM both trending to the system being more east.

    • Bob says:

      I’m throwing the Euro out of the door, it’s completely wrong because it doesn’t even have the President’s Day system. GFS, GEM and NAM are predicting a snowstorm while EURO does not. 3 out of 4 makes me think Euro is wrong, any thoughts?

    • Mike near Clackamas Town Center says:

      Euro=outlier

  8. Yevpolo1990 says:

    http://wxweb.meteostar.com/meteogram/link_pdiff.shtml?choice=kpdx+KDLS
    Easterly flow is really on the rise…southerly flow is at 1.2mb, easterly flow is about to get to 1.0mb if not higher.

  9. Yevpolo1990 says:

    A lot of organized showers coming from SW, could get interesting…

  10. Tyler Mode in Battle Ground says:

    On another note…even at my Vancouver station, it is the first time I’ve recorded ANY snow on February 16th. Probably 1.5-2″ there says my mom…they are on top of the measuring!

    • Bob says:

      I wish the local mets would include areas north of Vancouver more when making their forecast. They always include areas west, south and east of PDX but why not north of PDX?

    • W7ENK says:

      Because that’s Seattle’s territory.

  11. bgb41 says:

    10:15am picture in my front yard 2.5″ of snow

    • Bob says:

      Nice, just imagine this could of been Portland is the bulk of the precip hit us instead, congrats on your “unexpected” snow for today that no one forecasted even the wishcasters HAHA.

    • bgb41 says:

      This happened like this half a dozen times in Feb 2008. I got like 6″ of wet snow spread out over a weeks time while Portland got nothing.

      Still snow hard now. 33

    • Tyler Mode in Battle Ground says:

      Your front yard is far more scenic than mine lol

      Up to 33.9 here.

    • bgb41 says:

      Tyler, its so weird out here. You can drive three miles into Downtown BG where its 280ft and its almost nothing.

  12. Yevpolo1990 says:

    From UW weather page: “The WRF-GFS runs for this morning, 2011021612, are delayed due to problems in acquiring the initialization grids from NCEP. Sorry for the inconvenience. D. Ovens 10:30 am PST 2/16/2011.”

  13. Andrew Johnson says:

    My first take on the system shown from hours 108-120 is that it would start initially as rain or wet snow and then transition quickly to snow from N to S. At face value I’d say even the south valley would have a chance of some accumulating snow with this system. Of course who knows what the 18z will show.

    • Bob says:

      It will depend on what time of day the moisture starts. If it starts during overnight or morning hours then I think it will start off as all snow. We will have colder 850 temps to work with and offshore flow. You are correct however that as the system passes to our south, it will be all sticking snow down to the floor, Corvallis and Eugene might even get in on the action.

    • Andrew Johnson says:

      I would feel better if the Euro showed a remotely similar situation.

    • EA_TTD says:

      Which it doesn’t. 12z Euro keeps us bone dry Sunday.

  14. Bob says:

    Out to hr168, which isn’t that far out, and Seattle has the -12 line to them and it’s right on our doorsteps!

  15. ROFLMAO – Typical ALBANY. Now for weather geeks like us I KNOW this is infuriating. But for a 10, 11, OR 12 YEAR OLD WEATHER GEEK (like I was) it is DEVASTATING LOL

    TO MARK: here’s a good “on air” question:

    Why does the NWS allow forecasts to look like this?

    Point Forecast: 2 Miles S Millersburg OR
    44.64°N 123.06°W (Elev. 220 ft) Mobile Weather

    Today
    Showers
    Likely
    Hi 44 °F

    This one is ok

    Tonight
    Rain/Snow
    Likely
    Lo 30 °F

    I’ll let this one go

    Thursday
    Rain/Snow
    Likely
    Hi 46 °F

    My interpretation: Rain here/Snow THERE. Note: There means ANYWHERE ELSE BUT HERE
    LOL

    Thursday Night
    Chance
    Rain/Snow
    Lo 31 °F

    Friday
    Chance
    Rain/Snow
    Hi 46 °F

    Gettin’ a little REDUNDANT wouldn’t you say?

    Friday Night
    Chance
    Rain
    Lo 31 °F

    Now considering the pattern we’re under THIS one is just LAZY

    Saturday
    Slight Chc
    Snow
    Hi 48 °F

    Yep. I would put that chance at about 0.000013445%

    Saturday Night
    Chance
    Rain
    Lo 35 °F

    Sunday
    Chance
    Snow
    Hi 47 °F

    SAY WHAT? Oh I see. We see 46 degrees. The snow will still be flying!………IN ANCHORAGE!!!
    This is so silly LOL

    My only other question is:
    DOUBLEYOO TEE EFF ?

    Actually this silly but true rant is my official sign off rant from Albany. The Weather Station comes down in about an hour as we prepare for the big move to Salem on Saturday.

    LOL

    Watch Albany and Corvallis get just hammered after we move lol

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