Prepare For Some Brief Snow, Then Freezing Rain

Noon Wednesday:

Luckily the general sequence of weather events the next 2 days is still on track from yesterday’s post.  But of course as we get closer to these snow/ice events we can give you more detail.

First, it’s pretty obvious the cold air has arrived.  A very deep pool of cold-air has taken up residence east of the Cascades and is spilling through the Columbia River Gorge.  It’s deep enough that the air is spilling right over the Cascades too; that’s why all of us in the metro area are seeing the strong wind gusts.  That continues through Thursday, then backs off dramatically Friday.  Stay warm!

HIGHLIGHTS FOR WESTERN VALLEYS (INCLUDING METRO AREA)

  • This event will include far more freezing rain then snow, I doubt kids will be making snowmen this time around.
  • Cold and windy through Thursday, lots of clouds and even flurries are possible through midday Thursday.  This WILL NOT AFFECT ROADS.
  • Thursday AM should be dry for a clear commute.
  • A wave of snow showers or even steady light snow moves through our area 4-9pm tomorrow afternoon/evening, it’ll spread from south to north, arriving in Salem as early as noon or just beyond.
  •  A Trace to 1″ snow is likely for most of us in the western valleys before a transition to freezing rain tomorrow night.
  • Heavier precipitation (freezing rain) should be here for the Friday AM commute, with temps mainly below freezing for most areas west of the Cascades.
  • It’s possible that Friday afternoon many of us will see mainly wet roads south/west/north metro away from the Gorge.  This happened during the last two freezing rain events when we thought a large area would see freezing rain and instead it was confined to the central/east metro area.  In general conditions IMPROVE during the day Friday.
  • So an ice storm (with tree/powerline damage) is unlikely west of the Cascades or in most of the metro area.  Temperatures gradually warm above freezing most areas on Friday afternoon.
  • A warming southerly wind late Friday night or early Saturday ends the freezing rain threat outside of the Gorge at that time.

 

COMMUTERS

Tomorrow morning will be dry, or just flurries.  Tomorrow evening is a tough one.  You wouldn’t expect a trace to 1″ snow tomorrow evening to cause a commuting nightmare AGAIN right???

But 3 big issues…

1) A PBOT official mentioned on-air yesterday that they would “consider using salt in the future” which I assume means they have no plan to use it the next few days.  Translation: expect frozen/icy roads = if you don’t have 4×4 and/or chains you may have trouble.

2) ODOT will likely use some salt in spots again (remember how clear uphill/westbound 26 was at Sylvan after the snowstorm?).  If not, freeways could become a frozen hell again tomorrow evening since whatever chemical they sprayed on roads didn’t seem to have any effect during the last two evening traffic chaos events.  Roads froze anyway.

3) Our freeways are jammed in the evenings any typical day; I covered that in the summary of the December 14 freeway gridlock.

IF WE GET LUCKY IT’LL JUST BE LIGHT FLURRIES TOMORROW EVENING, BUT JUST ONE INCH OF SNOW = “FREEWAY GRIDLOCK EVENT” IS A POSSIBILITY

 

SCHOOL ADMINISTRATORS

For the metro area I wouldn’t cancel school, but keep a close eye on the radar in case precipitation is arriving hours ahead of time and kids need to get home before 4pm.  If our forecast is correct, buses should have no problem dropping kids off during that 2-4pm time period.  Friday will likely be a snow (ice) day since most areas will see icy roads to start.

COLUMBIA RIVER GORGE

Sorry, more snow!  4-8″ from Thursday evening through Friday night central/eastern Gorge (east of Multnomah Falls).  Freezing rain west of Multnomah Falls after tomorrow evening’s 1-2″ snowfall.

COAST

Too warm for snow or freezing rain, although maybe a valley near the Coast Range could see brief freezing rain Friday AM.

 

WEATHER DISCUSSION:

Models weren’t dramatically different either last night or this morning.  They are all quite light on precipitation tomorrow afternoon evening.  Check out the ECMWF total precip ending 10pm tomorrow

ecmwf_10pmpcp

That’s enough for a grand total of 1″ at most, the reason I’m thinking we’ll get very little snow out of this.  Also, there is plenty of above-freezing air moving in overhead tomorrow evening.  Check out the WRF sounding for 7pm tomorrow.

wrf_7pmthursday

That’s likely freezing rain not snow.  And the warming continues through the night.  While talking to Brian MacMillan this morning we noted that was the ONE THING that models have nailed in every weather event this winter, the profile of the atmosphere overhead.  In general, snow has transitioned to freezing rain when we expected it to in each storm.  It’s actually easier to forecast what’s going on at 3,000′ then here at the surface.  Due to all this I’m pretty confident this is more of a freezing rain event than snow.  No model right now is showing any significant snow west of the Cascades.  The WRF does have some decent precipitation over the mid-valley tomorrow midday/early afternoon, but thinks temperatures may be a little too warm for significant accumulation.

As mentioned yesterday this cold air mass at the surface isn’t as cold as what we saw during the last two events.  So it’ll be easier for temps to rise above freezing in much of the metro area Friday midday/afternoon.

Chief Meteorologist Mark Nelsen

 

32 Responses to Prepare For Some Brief Snow, Then Freezing Rain

  1. JJ78259 says:

    It looks like this will be just cold rain followed by lots warmer rain thru February which is normal winter weather. Portland has made the Salt decision though just in case. 55 degrees and more rain by the end of the month!

  2. Anonymous says:

    7PM Just left Vista House -a bit breezy, 60-70’s MPH gusts up there.

  3. marinersfan85 says:

    Whatever happens tomorrow, I’ll remain unbiased. This winter is already an A+ in my book.

    I just hope Oregonians have figured out how to drive in this after what might be event #6 tomorrow. I have no intention of sitting in place driving home tomorrow. So if you drive a Mercedes or bmw, just don’t drive.

    • Jake-(Gresham near Nadaka Nature Park) says:

      It’s been a A- for me too much ice! But I already know I need to move out to Hood River or something. 😛

      To give an example. The first ice event back in December downed a tree on a power line that ripped a steel streetlight right from its base (bolts and concrete went together). Still, haven’t replaced and it’s dangerous because the light covered the corner. I have to crawl with my car going around there. Can’t see a thing.

    • marinersfan85 says:

      I don’t base my grades on inconvenience.

    • Jake-(Gresham near Nadaka Nature Park) says:

      No man I’m just saying the ice does damage. It just got worse from there over here. (_)

  4. Donaleen Kohn says:

    We have to drive across the coast range tomorrow. Which route should we take to Portland from Yachats?

    • marinersfan85 says:

      Pay attention to the radar and temperatures. Its your best bet.

    • boydo3 N Albany says:

      You’ll be fine. Just head down I-5 and take hwy 34 through Corvallis.Take hwy 20 west to Newport and cruise south down the coast. For a slower, curvier and more nauseating drive take hwy 34 to Waldport then turn left at 101. The weather down here should be inconsequential.

  5. marinersfan85 says:

    I was starting to doubt the extent of the cold air today, while seeing mid 40’s throughout the valley. But my temp has dropped from 45 to 39 in a couple hours. 3 degrees of that drop happened in the last half hour.

  6. Jake-(Gresham near Nadaka Nature Park) says:

    Man, I was poo pooing everyone’s concern on the winds speeds. Just had a gust rip through my neighborhood of idk what speed (about 40+ or so?). Didn’t just shake the house. It roared through the street. Jeez. Fir trees would be down for sure if it wasn’t for the dry ground. Thank goodness for that!

  7. ZR in the forecast for me tomorrow night, which is unusual up this way (though it’s happened before). But… dome.

  8. Sapo says:

    Looking like a weak event but just enough to mess up the roads. That first band of precipitation/showers around 4 PM or so tomorrow looks pretty weak on the models, just enough for a trace or a half inch for most areas.

    The heavier precipitation arriving early Friday morning should be all ice for at least a few hours.

    I doubt much snow accumulation will occur, most totals probably near a trace or a half inch. But roads are going to be a mess Friday morning

  9. Anonymous says:

    Hi mark can you use the weather station hat we have odell Oregon .
    odellwwt plant

  10. Lurkyloo says:

    This wind is kind of freaking me out — seriously, it seems stronger than it has been so far this season. Wish I had an anemometer (or whatever that wind thingamajiggy is called) …

  11. GTS1K' says:

    Power out up here as of 1:30. Ahhh, the sweet sound of a 4KW generator in the afternoon – NOT!!!

  12. Jake-(Gresham near Nadaka Nature Park) says:

    Had a chance to look at the latest Euro. Not good. It has switched gears and consolidated with the GFS on taking the low pressure system on a South to North trajectory. So no coming ashore into Oregon.

    Lots of snow for British Columbia….
    http://www.pivotalweather.com/model.php?m=ecmwf&p=sfcmslp&rh=2017020112&fh=72&r=na&dpdt=

    • Scooter says:

      Huh? “Not good” what the heck does that mean, I don’t get it. Is it a poor forecast or just disappointment caused by unreal expectations?

  13. Alohabb says:

    Rod hill…..little to no snow, some freezing rain.

  14. MobileNick says:

    “2) ODOT will likely use some salt in spots again (remember how clear uphill/westbound 26 was at Sylvan after the snowstorm?). If not, freeways could become a frozen hell again tomorrow evening since whatever chemical they sprayed on roads didn’t seem to have any effect during the last two evening traffic chaos events. Roads froze anyway.”

    This is the part that frustrates me so much about the salt vs de-icer argument that ODOT/PBOT makes. They claim that de-icer solution works much better yet snow/ice sticks to the roads even with the slightest accumulation

    Then they wanted to test salt and subsequently claimed it was “unimpressive” and of “limited usefulness” – what are they saying? They know more about snow/ice handling than midwest states that have used salt for decades?? These states have to deal with it much more than us yet we know a lot more than them?!

    • Jake-(Gresham near Nadaka Nature Park) says:

      Thinking about this a little more…

      I’m confused why we use MgCl2, honestly? With a water content of around 46% it doesn’t take a science major (tongue in cheek as I am one) to note that with our mossy, damp, and often wet environment. That won’t do much of anything. It probably just gets diluted further.

      We also have storm drains in shaded areas with fur trees that often have moss growing right on our roads. It catches leaves and in a good rainstorm causes localized flooding. Not sure why the city is so hesitant to use salt. It’d kill off that growth!

      Not like we don’t have a water treatment system for our rivers and streams. Sheesh.

      Personally, these CONS don’t seem to match our climate (source: Wiki):

      1) A minimum humidity level is required to absorb moisture from the air (32%).

      2) It’s more suitable in drier climates.

      3) In concentrated solutions it is very corrosive (again we dilute to 46%).

      4) It attracts moisture thereby prolonging the active period for corrosion (a salt is a salt).

      5) Rainwater tends to leach out highly soluble chlorides, if there is a high fines content in treated material then the surface may become slippery when wet, when less than 20% solution it has performance effectiveness similar to water.

    • Scooter says:

      I think much ado about nothing, it will probably be many years before we would have another event like the one in early January. By then the salt stored for years will have turned to rock and you will probably be living in another state anyway.

    • marinersfan85 says:

      I don’t know scoots. You kept saying all winter that nothing would happen. We’re on the doorsteps of event #6. Even though I doubt it happens. 5 events is incredible as it is. At some point, you should just move along. Pick up your ball and go home.

  15. runrain says:

    Am guessing after this event, next week’s “event” is just low-ish snow levels at, say, 1,000 feet or so?

  16. Roland Derksen says:

    Clear skies and a fairly stiff easterly breeze here this afternoon. The forecast up here for the weekend is some combination of rain and snow, possibly changing to straight snow for Sunday. Looks like winter is coming back!

  17. Alohabb says:

    I’m gonna start a new protest downtown. #nomorewinter

  18. Lurkyloo says:

    Hate the ZR! Hope it goes away quickly, assuming it shows up. PPS has the day off on Friday already, so hopefully no more snow days to add into the mix.

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