Monday Evening Update

9:30pm…

Get ready for strong wind tomorrow!  The National Weather Service issued a High Wind Warning this afternoon for the metro area and Cascade foothills, forecasting gusts as high as 60 mph from the east as cold & dry air out of Canada surges south and over the Cascades.

Most locations will see gusts in the 35-50 mph range, but the favored spots (Battle Ground/Hockinson) could see winds a bit stronger in gusts.  We’ll see how that works out.  Either way a beautiful day with the air turning very dry and blowing all the leaves off the trees.  Sunshine from sunrise to sunset.

Pretty much the same thing for Wednesday as my thinking from last night’s post hasn’t changed much.  Models are waffling on the cold air a bit.  For example the WRF-GFS says The Dalles will be 35 tomorrow and PDX’s high will be 40.  It’s running too cold.  I think it’ll be more like 38 and 45.  Or PDX could be even warmer.

I still don’t see snow west of the Cascades Thursday unless we get a spot up against the east slopes of the Coast Range or the Scappoose/St. Helens area.  Our RPM and the soundings from the WRF-GFS say no snow for the metro area since there will be a warm layer up around 3,000′.

Freezing rain west of the Cascades?  Looks unlikely, but there may be isolated spots of icing since it appears the precipitation will be holding off until close to sunrise Thursday.  This will be determined by how cold the airmass ends up over us by Wednesday.  We’re really not sure how well models are handling that airmass yet.  Here are the graphics I used this evening:

MarkSnow_TextPanel MarkSnow_TextPanel2

As for the Gorge…wow!  Evening models have a LOT of moisture for heavy snow/freezing rain.  We don’t lose the easterly flow, so the cold air is going to last awhile.  This COULD be a historic November snow/ice storm out there.  Take a look at the WRF-GFS snow forecast below…a solid foot or more in the central/eastern Gorge during the 24 hours from Thursday to Friday morning.  The thick ice (freezing rain) at the west end of the Gorge (Corbett and hills above Washougal) would be devastating with .50″ to 1.50″ rain equivalent.

or_snow72.84.0000

That forecast is ever so slowly backing off on snow here in the western lowlands.

So that’s it for now…batten down the hatches for wind tomorrow.

Chief Meteorologist Mark Nelsen

40 Responses to Monday Evening Update

  1. runrain says:

    Interesting that the Portland airport winds are almost as strong as those occurring at the Vista House. That will change, obviously, when the winds are more gap oriented tomorrow. Just a little bit beyond breezy here in Happy Valley today. That’s unusual in that we usually get strong east winds here in these conditions.

  2. Josh Gardner says:

    Comparing 12z NAM and WRF…

    Low placement/timing
    3-4AM.
    Agreement on timing, not on placement.
    Both bring the low in at or just south of Newport, NAM is slightly further south.

    Precip timing
    3-5AM.
    Agreement.
    South metro just after 3, PDX by 4, Clark County by 5

    925mb temps at 4am Thursday
    WRF shows <0c temp border right around Gresham, and into BG, as well as an area banked up against the coast range out towards Forest Grove.
    NAM is MUCH colder, likely due to to southerly low placement. Entire metro area <0c if not closer to at least <2c. Border is around Wilsonville, indicative of strong gorge influence

  3. alohabb says:

    Are the strongest winds yet to arrive? Or we have several more hours of the same??

  4. alohabb says:

    Transformer blew up and sounded like a dang plane crash in Aloha! Never heard anything like that before

  5. BigBank Hank says:

    Looks like another forecast bust by the talking tv bobbleheads.

  6. schmit44 says:

    Looks like gradient is peaking very soon. Starting to level off. Here is the 24 hour evolution of the east wind (Cross-cascade) highlighted.

    http://www.directpaintsaleswa.com/upload/gradient his.png

  7. Andrew (Beaverton) says:

    NWS has put a chance of snow into the forecast for the Portland area now…interesting.

    Also, i know the point and click forecast is a total joke, but interesting to see they have 1-3 inches listed for the 500 foot level of the West Hills.

    As a side note, many times in the past we have seen these scanrios play out longer than expected as the gorge winds are never properly portrayed by the models. Any thoughts on this?

  8. pappoose in scappoose says:

    Bring on the WET-BULB EFFECTS!

    NATIONAL WEATHER SERVICE PORTLAND OR
    909 AM PST TUE NOV 11 2014

    IF THIS WERE DECEMBER OR JANUARY…THIS OVERALL PATTERN WOULD BE NEARLY PERFECT FOR LOWLAND SNOW…WITH LOW PRESSURE APPROACHING FROM
    THE SOUTHWEST AND A ROBUST COLD AIR MASS IN PLACE ACROSS THE PAC NW. FOR SNOW TO OCCUR IN THE WILLAMETTE VALLEY THERE WILL NEED TO BE
    SIGNIFICANT WET-BULB EFFECTS…WHICH WOULD REQUIRE A FAIRLY HEAVY BATCH OF PRECIPITATION TO MOVE INLAND WED NIGHT/EARLY THU. LATEST NAM
    BRINGS PRECIP INTO THE FAR SW PART OF THE FORECAST AREA BETWEEN 06Z AND 09Z THU…AND NOT TO KPDX AND THE COLUMBIA GORGE UNTIL AT LEAST
    15Z. SLOWER MAY BE BETTER NEAR THE GORGE AS THE INCOMING MOISTURE WILL BE FIGHTING SUCH A STRONG EAST WIND AND VERY DRY LOWER PART OF
    THE AIR MASS. IF THE NAM MODEL SOUNDINGS WERE TAKEN AT TOTAL FACE VALUE…KPDX WOULD SEE SEVERAL HOURS OF SNOW THU BEFORE TURNING TO
    -FZRA. EVEN THE KSLE NAM MODEL SOUNDING PROVIDES A 3-6 HR PERIOD OF -FZRA BEFORE CHANGING TO RAIN. THE COLUMBIA GORGE IS LIKELY TO GET
    SUBSTANTIAL SNOWFALL. THE 00Z WRF-GFS SHOWS AT LEAST 5-10 INCHES OF SNOWFALL 12Z THU TO 00Z FRI FOR THE GORGE. THE OFFSHORE LOW-LEVEL
    FLOW IN THE COLUMBIA GORGE NEVER COMPLETELY ENDS…BUT DOES WEAKEN CONSIDERABLY FRI. LOTS OF THINGS TO MULL OVER…BUT EXPECT WINTER
    STORM WATCHES TO BE ISSUED FOR THE AFTERNOON FORECAST. WEISHAAR

  9. vernonia1 says:

    I know most newer cars have a outside temp display. Anyone know if you can “after market” these?

  10. W7ENK says:

    Sunrise over the Hawthorne Bridge from Downtown.

    90 minutes compressed to 90 seconds.

    Thank you Veterans!

  11. schmit44 says:

    738am: Cross-Cascade gradient now nearing -21 millibars

  12. Jason Hougak says:

    The winds gonna get crazy as it’s going pour off the Cascade and foothills. Another flirt/ tease west side, but boy the gorge looks like it will be a good one. Too bad it wasn’t deep winter or we’d all have some fun. It’s still early who knows what this winter will bring. Love all the weather action though. Went to bed at 33F, woke up and temps going up and down like a yo-yo between 37-39F, winds must be blowing, yet to find out.

  13. alohabb says:

    Holy bitter Cold East Wind Batman!!!!

  14. Tyler Mode says:

    45 degrees with a persistent east wind here. Did get down to 43 briefly. Meanwhile Brush Prairie dropped to 30.

  15. Longview 400 ft says:

    Currently 32.7

  16. schmit44 says:

    Cross-cascade gradient now at -13.3mb as of 12:51am

  17. runrain says:

    Gusting to 52 at Vista House now.

  18. Ben T says:

    I’m in!

  19. schmit44 says:

    11/10/2014 Oregon (All) Temperature Summary

    Warmest:
    High:69 at Brookings (US 10( 150 ft) & Gold Beach (US 1(60 ft) & BROOKINGS(79 ft)
    Low: 52 at Brookings Airpor(459 ft)

    Coldest:
    High:23 at HOWARD Mt Howard(8150 ft)
    Low: 11 at CROW FLAT (5172 ft ) & HOWARD Mt Howard (8150 ft )

    Largest Diurnal Change: 34 degrees
    Lorella (54/20 ) (4160 ft )

  20. vernonia1 says:

    wow….down to 34 here already! brrrr………….

  21. I like the NWS reference to the Dec 2003 downslope event. One of the biggest east wind events we’ve had here in east CC since 1990.

    WE HAVE HAD DAMAGING DOWNSLOPE WINDS IN EASTERN CLARK AND CLACKAMAS COUNTIES WITH A SPOKANE TO NORTH BEND GRADIENT PEAKING OUT BETWEEN 20 TO 21
    MB IN EARLY DECEMBER 2003. SO EVEN IF THE GRADIENT ENDS UP A LITTLE LESS THAN CURRENTLY FORECAST…OTHER FACTORS DISCUSSED BELOW WILL
    LIKELY END UP DRIVING WHETHER OR NOT DAMAGING WINDS WILL SURFACE IN EASTERN CLARK AND CLACKAMAS COUNTIES.

  22. orwxguy says:

    Sounds like it may be a fun day at Vista House…

  23. Jesse-Stevenson says:

    I’m liking the forecast Mark. 😀

  24. Tyler Mode says:

    No matter what happens, at least there is some weather excitement!

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