Crazy Weather Week Ahead

Fall 2014 has been the warmest ever so far…but that’s about to change in a big way.  We’re less than 2 days away from wind and temperatures we would typically see in mid-winter.

Models haven’t backed off a bit in the past two days.  The Pacific Northwest will get a chunk of the unusually cold (for November) arctic air mass diving into the USA this week.  We’ll be on the “left” (no surprise?) or west side of a truly massive surface high pressure area sliding down into Montana. MarkColdThisWeek_ThePlan With a huge area of high pressure to our east, the wind will be rushing out to the west, over the Cascades, through the Gorge, and down into the western lowlands of Oregon and Washington.

SUN

Enjoy the next 3 days of bright sunshine!  It’ll be a very dry air mass coming in from the northeast…the driest we’ve seen since last winter.

WIND

The strong wind arrives overnight Monday night and into Tuesday morning.  For most of the metro area, the peak wind will be during the day Tuesday.  In the Gorge the wind will likely be strongest Wednesday night as a weather system approaches and the wind zone gets scrunched down into a smaller area close in to the Gorge.

MarkEastWind_DownslopeToo MarkEastWind_DownslopeToo2

Those speeds will be strong enough to cause scattered power outages and down some trees.  The air mass will be incredibly dry since it came out of the arctic, so leaves will blow around quite easily.  Models have been unusually strong with the low-level wind field, showing 50-60kt wind just a short distance above the surface in the Portland metro area. kpdx.th There is an outside chance we get a mountain wave developing in the lee of the Cascades over Clark County, but generally that has occurred in a slightly different setup in the past…different wind direction higher up in the atmosphere.  I actually found the maps from Dec 4, 2003 and Dec 12, 2004 when 60 mph gusts hit Hockinson and Battle Ground areas, plus some damage around Mt. Tabor too.  Those maps were sitting in a file folder, old style!  A nice dinner break perusing 11 year old cross-sections!

FREEZING WEATHER

– Prepare for mild freezing west of the Cascades (25-30 degrees), but not cold enough to freeze pipes.  Lows in the windy parts of the metro area will hardly get below freezing.  I could see PDX not even dropping to freezing the next 4 nights.  Any spot that goes calm Tuesday night could drop well down into the 20s, but I think those will be very isolated areas.  This is not a major freeze west of the Cascades, but it will be the first frost for many of us…we’re overdue for that this fall.

WHAT ABOUT SNOW OR FREEZING RAIN?

– Just about everyone west of the Cascades (maybe everyone) can FORGET about snow when moisture returns Wednesday night.  The air mass won’t be cold enough through a deep enough layer to support that.  There is a slight chance it starts as snow up against the east slopes of the Coast Range…we’ll take a closer look at that over the next few days.

– Freezing rain and snow is looking very likely east of Troutdale/Washougal in the Gorge beginning Wednesday night.  Where the cold air is thinner (Corbett, east of Washougal etc…) freezing rain is a good bet.  I already told my kids there’s a good chance they have an “ice day” Thursday out there.  Here is the latest WRF-GFS precipitation forecast ending Thursday morning; enough for 2-6″ snow in the Gorge if this is the case.  or_pcp72.84.0000

– It should be slightly too warm for freezing rain in the metro area, but as of tonight it’s still a close call.  Hopefully we can rule that out by Wednesday morning when the air mass is in place.  That “no frz rain” forecast is based on past events and on the assumption that models are bringing too much cold air over the Rockies and through the Gorge.  The latest 00z GFS agrees with this; you can see it’s forecast of each precipitation type.  gfs_ptype_accum_portland_17 Freezing rain or snow is not shown here in the valleys.

Chief Meteorologist Mark Nelsen

47 Responses to Crazy Weather Week Ahead

  1. paulbeugene says:

    46F in Hope, BC, 50F in Omak, WA at this hour. Arctic front still ways away. Still time to put the garbage cans etc away in Gresham, Troutdale, etc.

    Euro backing off on the idea of reload of arctic air into the Rockies etc for this weekend, sending it toward the Upper Midwest, Great Lakes. Instead, more precipitation, with systems headed to south Oregon, north California in split flow.

    • runrain says:

      Looks like NWS has backed off a bit on the winds, too. It sounds like they are going to issue a wind advisory with the afternoon package, however.

  2. Ron Keil says:

    Got the picnic basket filled: Bottle of wine, my camera and anemometer. Crown Point wind party time Wednesday! Only if it’s 100mph or higher, though.

  3. goducks09 says:

    Any liklihood of moisture creating some evaporational cooling to help our snow chances?

    • W7ENK says:

      With sub-zero dewpoints at the surface, of course. But 850mb temps are forecast to be +1C at the onset of moisture, so the chances of snow making it to the surface in Portland are greatly diminished, depending entirely on the thickness of that warm layer above. ZR or sleet are a good bet for areas close to mouth of the Gorge, but it’ll be a close call here in PDX Metro.

    • Mark Nelsen says:

      A pile of sleet would be so much better than freezing rain for driving on. That’s what I’m hoping for at home.

    • High Desert Mat says:

      Oh Mark, you know your like a kid in a candy store with this weather. I think you’ll take zr any day over plain old rain. Now stop whining and rub some dirt on it lol.

    • High Desert Mat says:

      Hence why you moved to where you did.

  4. Scott says:

    I have to drive to Hood River Friday morning, for the weekend. Looks like a potentially snowy drive out 84?

    • Tyler Mode says:

      Snowy and icy…I would postpone or do it early if possible.

      I drove out there a couple years back with the freezing rain and wind, I’ve never been so scared driving before, it was nuts!

    • Scott says:

      Thanks Tyler. Snow I can deal with. Ice is not so fun…Not sure I have the ability to travel sooner. We will see…painful.

  5. Question: Sometimes when we get a huge gulp of cold air to the East, it comes pouring through the gorge (and maybe down the valley). But other times, we seem to have so much cold air and pressure gradient that the cold air just pours over the Cascades, down the sloops of the foothills, and inundates the whole valley. Does anyone know what condition result in the latter? Is that a possibility with this next surge?

    • Tyler Mode says:

      Generally, if the cold air isn’t any deeper than the Cascades are tall in most areas (4-5000′) than the winds just pour through the gaps and gorge. If it’s deeper than that, then it flows over the Cascades.

      At this point it looks deep enough for a while to pour over the mountains the next two days. Then it turns to more of a gap wind by Wednesday.

  6. Joe says:

    So, the strongest wind in the Gorge will be on Wednesday then? Crown Point?

  7. alohabb says:

    The leaves are starting to move around a bit. Gonna be a COLD week, windchill wise for sure!!

  8. Jason Hougak says:

    Plants are going to go into shock with temps going from 40’s to mid 30’s down into the 20’s.
    Overall pattern brings cold to the Midwest and east again. Might end up with the same locked up pattern again. The high over Alaska is shoving everything east or we will get under cut by the flow out of the southwest.

    • David B. says:

      Or if the ridges continue to retrograde like this one is forecast to, we’ll have another multiple-arctic-blast winter.

      We shall see. It is way to early to jump off the cliff.

    • vernonia1 says:

      if nothing else…my neighbor covers his plants ….some with black plastic…some with towels. One year he put towels over one precious plant…then a bucket…it stayed happy all winter 🙂

  9. W7ENK says:

    Yeah, I like the wind map. It clearly shows a stretch of wind maxing out at 25kts at the surface. A cold, stiff 30 mph wind should be quite refreshing. Should also keep the temperatures up for us, so I don’t see a hard freeze. I also don’t see frozen precip, except for maybe a little ZR at the mouth of the Gorge, of course snow stays East of Cascade Locks, per the usual.

  10. The Bad Forecaster says:

    And as usual when the Portland area gets it all. The Tacoma and Seattle areas will get NOTHING and LIKE IT. 🙂

  11. schmit44 says:

    11/9/2014 Oregon (All) Temperature Summary

    Warmest:
    High:71 at Rome(4049 ft)
    Low: 51 at Brookings (US 10(150 ft) & RED MOUND(1753 ft) & Port Orford(0 ft)

    Coldest:
    High:43 at NORTH FORK(3120 ft) & MCKENZIE(4800 ft) & HARL BUTTE(6071 ft)
    Low: 21 at CROW FLAT (5172 ft )

    Largest Diurnal Change: 39 degrees
    Lakeview, Lake C (66/27 ) (4734 ft )

    Heaviest Rainfall:
    1.18″ at Mount Hood Meado(5249ft)
    0.90″ at MILK SHAKES(5600ft)
    0.85″ at DW6879 Union(2792ft)
    0.75″ at LOG CREEK(2800ft)

  12. Brian Leroy says:

    Meanwhile here in boring seattle well get our typical run of the mill 10 mph “wind storm” while u guys down south get The Nothing from the never ending story, lol

    • David B. says:

      Bellingham gets it good during these sort of events, too. If you want the strong east wind, you need to be near a gap in the mountains.

      Though it’s going to be stronger than just 10 mph in Seattle. More like 15 to 20. The cold air is forecast to be really thick with this one, so we’ll get gap winds through the lower Cascade passes like Snoqualmie, too.

  13. I think another driving factor for the possible high winds and not just the strong PDX-DLS/OTH-GEG gradient is the higher than normal 1000-500mb thickness/height values observed over PDX. Typically(but not always) when we get shots of cold/arctic air these are much lower in the 520s-530s, and now they are forecast to be 540s-560s. Due to this I wonder if the warmer temps/layer aloft compressing the cold layer leads to good mixing potential and a big event. I guess we’ll find out.

  14. Jake-(Gresham) says:

    Just watch the East get a massive nor’easter out of this cold.

    Bahumbug!

  15. I have no idea where Mark gets his 2-6″ snow forecast for the Gorge. That precip map only goes through early Thursday morning – and quite a bit will fall AFTER 5am that day. Last time I looked it was closer to 6″ near The Dalles and a foot in the central corridor

  16. alohabb says:

    So you’re saying there’s a chance

  17. Nice, update…. I like the fancy wind graphics.

    NWS is contemplating pulling the trigger on a High Wind Watch now for Portland/Vancouver Metro. Hmmm….

  18. pappoose in scappoose says:

    “Batten down the hatches – quick, men.”

  19. Already one of the chillier nights this fall…If things stay clear I could probably get down near freezing. My first frost this fall wasn’t until November 1st.

  20. Appears to be shaping up to be like a Dec 2003 or Dec 2004 type east wind event here in CC. Lost a 90′ fir during the Dec 4th 2003 one. Don’t want a repeat of the Dec 1983 event though.

  21. BoringOregon says:

    Watch it will Snow!!

  22. No snow says:

    Oh course it’s not going to snow. It’s November in Portland.

    🙂

    Nice wish casting everyone. Keep up the good work. I’ll be busy boarding up my windows for the “hurricane force” winds.

  23. Tyler Mode says:

    Nice update. Agreed on the no snow…no model shows cold air through the entire column.

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

    First! Bring it on!

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