Winter Storm Watch In Gorge & Flood Watch

9:30pm Tuesday…

A major ice storm is likely on the way for the Columbia River Gorge late Wednesday night and Thursday.  A dumping of snow is also likely in parts of the Gorge too.  This event could easily rival what we saw 2 weeks ago; mainly because we have so much precipitation on the way.  As a result, the NWS has issued a Winter Storm Watch for the Gorge.  Remember a watch means an event is possible, but not imminent.

The short break with quiet weather has been nice.  But it’s pretty clear our wild December weather is going to resume soon and continue through Christmas Week.  This month is beginning to remind me of those wild winters around 1995-1997.  Specifically it seems like December 1996 right now.

This is what I’m thinking for the Gorge on Thursday:

MarkFreezingRain_Gorge

This is a somewhat unusual situation where the cold air is not already in place, but will be sucked into the Gorge tomorrow night by an approaching front and low pressure.  Cold and dry air will be sliding south through Eastern Washington.  There is still a (getting smaller) chance that models are overdoing the amount of cold air headed south.  We should have a good handle on that by sunset tomorrow.  If it’s still in the mid 40s at Yakima and Pasco tomorrow afternoon? That sure won’t inspire confidence in a real cold Gorge.

What will be typical is the distribution of frozen precipitation with a deep cold layer producing mainly snow from Cascade Locks eastward and a much thinner layer producing only freezing rain (glaze ice) in the Corbett/Cape Horn areas in the western Gorge in the east wind zone.  In between from Bridal Veil to Bonneville we’ll see a mix.  It’s even possible that at freeway level temperatures won’t be cold enough to cause issues until you get closer to Bonneville.  Regardless, I think there will be lots of schools closing Thursday from Corbett to The Dalles.  I think it’s unlikely we see freezing rain creep into the east side of the metro area like two weeks ago.  Airmass coming in isn’t that cold.  Or at least that’s the plan for now.

Whatever falls, there’s going to be A LOT of it.  Take a look at the 24 precip total from 4pm Wednesday to 4pm Thursday…about 2″ liquid is likely.

or_pcp24.48.0000

That’s a crippling ice storm, or several inches of heavy sleet, or 15″ of snow ending with sleet/ice depending on the location as mentioned above.  Our RPM shows some huge ice accumulation in spots.

RPM_ICEACCUM_USA

DON’T READ IT TOO LITERALLY (FOR A SPECIFIC SPOT); the terrain on the model doesn’t allow it to see the Gorge well.  Just note the general picture shows there is going to be a lot of ice where the cold air is thinner (near Cascade crest and western Gorge)

I’ll post again tomorrow once we’re within 24 hours of the event.

Now let’s talk flooding.  We have a bunch of rain on the way Thursday and the NWS has issued a Flood Watch once again.  As of now they are thinking some rivers will see minor flooding once again; specifically the Tualatin, Pudding, Luckiamute, Nehalem, and Johnson Creek.

MarkWarnings_FloodWatch

This is another very wet system.  Although the totals don’t look too extreme compared to earlier in the month, it’ll only add to the waterlogged slopes/soils in our area.  We can expect more slumping land and mudslides.  The southern part of our viewing area is going to be hit harder once again like this past weekend.  Our RPM shows quite a bit more rain in the south Valley than up in western Washington.

RPM_12KM_Precip_NWOR

There will be plenty more “cold rain” beyond Friday morning through next week.  Most of the next 10 days we’ll see snow above 3-4.000′.  The Thursday storm is the only one with very high snow levels.  That’s great news for Christmas Break at the ski areas!

Take a look at the next 10 day’s worth of precipitation from the latest GFS model and ECMWF.  Both show 4-6″ rain in the valleys and 10-20″ precipitation in the mountains!

It appears that we may totally blow away our wettest month on record easily at this pace.  13.35″ is the record back in December 1996.  Wow…

Chief Meteorologist Mark Nelsen

 

 

 

53 Responses to Winter Storm Watch In Gorge & Flood Watch

  1. marinersfan85 says:

    Gonna call a bust for the Gorge. 39 degrees with a dew point of 31 in Yakima.

    If I’m wrong I’ll eat crow.

  2. paulbeugene says:

    Wed 1pm

    Still 46F in The Dalles. Dicey forecast for snow/freezing rain in east gorge. Stiff north winds, lowering dewpoints in upper 10s/low 20s in NE Washington.

    Looks good for good dump of snow at north Oregon Cascade passes with changeover to rain before back to snow again by 4pm Friday.

    Periods of snow through Monday in the mountains, certainly won’t be a high visibility day at the ski area.

    Next onslaught of moisture will be late Monday into Tuesday, with at least a half day of 850mb temps getting as high as 5C, so rain at pass elevation then back to cooler again afterward.

    850mb temps in -3 to -5C range forecast by computer models for the trough that arrives before Christmas. With onshore flow, best guess is snow levels down to 1500-2500′. Need -7 or -8C 850mb temps before I even hope to see snow on valley floor during onshore flow.

    Long range:
    Seems persistence is the best bet for the next 10-14 days with progressive pattern, with mean trough remaining west of the Rocky Mountains, more and more rain, more and more mountain snow.

    The GFS operational in the long range (12z) looks pretty splitty and el nino-ish but the ensemble mean is pretty bland appearing without clear signals in any direction beyond day 10.

    Portland likely to have 15-17″ of total precipitation for month of December. Would not be surprised to see some moving earth in the West Hills during the coming week (this was certainly a problem back in 1996 with all the rain).

    • High Desert Mat says:

      Paul, on Tuesday the ensemble mean barely gets above 0C for the 850 Mb temps. It shows that the 12z operational was an outlier for that particular timeframe. It spikes about late Monday til only about Tuesday afternoon and then crashes back down. I dont see a total washout at the pass level with those temps. Then the mean drops to about -5C on Xmas eve. I wish we could all get a white Xmas and New Years.

  3. Prune Hill Outpost says:

    Hi Mark we moved to Skamania County a couple miles north of Cape Horn. Same commute question that I saw earlier; are we going to be okay to go into Portland or are we in the freezing rain again?

    • marinersfan85 says:

      Watch the weather. Pick up a thermometer. It’s a 50/50. Right now. No one will actually know the answer until the event starts.

    • Dean Baker says:

      1200ft Cape Horn / Biddle Butte, we had 1.25″ ice with the last ice storm. Hoping to escape this time as the young apple orchard trees were not happy. Washougal river road was clear with most of the last system, so that may be a good route to travel if it is iced higher up in wind exposed areas. If mount pleasant school is closed it is hazardous near cape horn.

  4. Jesse-SW Portland Suburbs says:

    Definitely missing Stevenson during potential events like this!

  5. Jason Hougak says:

    Skiing some superb snow up at Tline. Snowing down to Silent Rock on 26.
    That 18Z GFS should be scrapped! It’s alway gets my hopes up for an arctic invasion only for the next run to destroy it.

  6. JohnK316 says:

    What do the prognosticators predict now regarding snow on the valley floor? Possibility for January or February?

  7. Pete says:

    AREA FORECAST DISCUSSION
    NATIONAL WEATHER SERVICE PORTLAND OR
    1021 AM PST WED DEC 16 2015

    … CONFIDENCE FALTERS IN THE WINTRY PRECIP FORECAST FOR THE GORGE…CASCADES…AND UPPER HOOD RIVER VALLEY AREAS. MODELS REMAIN INSISTENT THAT COLD AIR WILL ARRIVE TO AREAS EAST OF THE CASCADE CREST THIS EVENING AS COLD HIGH PRESSURE PUSHES SOUTH INTO THE ROCKIES AND DEVELOPING EAST WINDS WILL ADVECT THE COLD AIR INTO THE GORGE. DESPITE THAT…THERE ARE TWO SOURCES OF UNCERTAINTY.

    FIRST…THE COLD AIR IS NOT FORECAST TO BE VERY COLD. CURRENT TEMPERATURES AROUND HOOD RIVER ARE IN THE 40S AND MOS GUIDANCE SHOWS A LOW TEMPERATURE TONIGHT AT THE DALLES ONLY AROUND OR SLIGHTLY ABOVE FREEZING. AS TEMPERATURES WEST OF THERE IN THE CENTRAL AND WESTERN GORGE WOULD LIKELY BE A COUPLE OF DEGREES WARMER…AT LEAST NEAR THE RIVER…THE MAIN PRECIP TYPE IN THE GORGE COULD END UP BEING RAIN. HOWEVER IT MAY BE A SCENARIO IN WHICH PRECIP IS MOSTLY RAIN AT THE FLOOR BUT MOSTLY SNOW JUST A FEW HUNDRED FEET ABOVE WITH SIGNIFICANT SNOWFALL ACCUMULATIONS THERE. OR THE AIR COULD COME IN COLDER THAN FORECAST AND THERE COULD BE SIGNIFICANT SNOWFALL DOWN TO THE RIVER.

    THE SECOND ISSUE IS THE COLD AIR ITSELF. THERE HAVE BEEN PAST INSTANCES WHEN COLD AIR WAS FORECAST BUT SIMPLY FAILED TO SHOW UP. UNFORTUNATELY THAT IS NOT SOMETHING THAT CAN BE DETERMINED WITH MUCH CERTAINTY AT THIS POINT IN TIME AND THERE LIKELY WILL NOT BE A STRONG INDICATION ONE WAY OR THE OTHER BEFORE THIS EVENING. WITH ALL OF THAT BEING SAID…DUE TO CONTINUED LOW CONFIDENCE…WILL STICK WITH CURRENT WINTER STORM WATCHES FOR NOW AND MAKE A FINAL DECISION ON WHAT TO DO WITH THEM WITH THE AFTERNOON FORECAST PACKAGE.

  8. Ryan says:

    Mark,

    I am a weather geek looking to learn more about reading models and analyzing weather in general…something a little more than weather 101 I guess. Do you have any tips on classes I could take, either in person or online? Thanks.

  9. It’s not like December 1996 for me unless I get at least a foot of snow on the ground. (Actually, I’d be very happy to get 4-6″ even though it would fall short of 1996 standards for me.)

  10. Paul D says:

    GO FOR THE RECORD! Blow it away! YES!! 🙂

    • Dave in South Salem (500') says:

      Wasn’t too long ago on here that people were whining we would have another dry winter. So much for that idea!

    • “Wasn’t too long ago on here that people were whining we would have another dry winter.”

      Yes, many were, despite how the strongest El Niño events (of which this is one) do not tend to be dry for us. Oh well, at least I can gloat about being right in my prediction that this probably wasn’t going to be a dry winter.

  11. A cold rain here yesterday, but the rewards of having it, will be shown today: Sunny skies will reveal a snow laden view of the local mountains. My total amount of precipitation for this month so far is 7.69 inches. We MIGHT make this our wettest December on record, but I think it will just fall short of December 1972. (16.7 inches)

    • Some showers of lovely 34 degree rain at my place this morning. One of those days that makes me wish I lived in the foothills at about 1000 to 1500 feet elevation, just high enough to get some more snow events without being high enough to have a long, snowy winter.

    • One final post for the morning: Moisture does really seem to be heading more into Oregon than Washington or BC the past few weeks, but that merely makes up for the previous months (basically, everything from August on) when Oregon was getting shorted in the moisture department compared to points further north.

      For me it’s only a slight exaggeration to say the rainy season began in mid-August this year; I think it was the 15th when I had well over an inch. But then it returned to hot and dry for a couple weeks until I got another big dump of rain in early September, and from then on there never was much of a gap between days with precipitation, even though temperatures were generally above average until early November.

    • One forecaster in my locality(Vancouver BC) is giving the possibility of some initial freezing rain or sleet here tomorrow. I’ll watch for that.

  12. JJ78259 says:

    Precipitation records were made to be broken, December 96 is going down hard. Never thought it would happen. That was a bad month I remember the dry well drainage on Wake Crt in Milwaukie couldn’t keep up and almost flooded my garage.

  13. alohabb says:

    This is going to be an interesting week or so. 2 websites and iPhone showing snow of 1″or less on the 25th. Wouldn’t that be crazy fun. But that could all change so quickly. Stay dry!

  14. […] local amateur forecaster Cap agrees, and so does my colleague Mark Nelsen of Fox-12. He posted a dire Gorge forecast on his […]

  15. Jason Hougak says:

    http://tinypic.com/view.php?pic=mwe1dx&s=9
    That’s a nicely colored state

  16. pappoose in scappoose says:

    Hahaah! Beware the slumping land!
    How about some mass movement, Mark!

  17. 6z GFS no real improvements. Ridge builds over Aleutians, amplifies some, but as with 00z it is shoved southeast too quickly. Onto 12z!

    12z GFS in 4 hours 43 minutes

  18. Destiny says:

    Do you think we will get any snow out near Salem?

  19. Wow action packed post full of goodies and details, Mark. Thanks

    We absolutely have trend now with the GFS/EURO to build the Aleutian ridge stronger, more amplified, and positive anomaly a bit further north-northwest on each subsequent run(I have done model comparison from both models past 3 or 4 runs HR 168-192 and it is very apparent.) Nothing arctic YET, but the improvement is a great sign. I also notice the cold/bitter air is moving into Alaska/Yukon a bit more progressively sooner each run too. By day 8 it’s moving into northern BC. By day 10 it’s approaching southern BC. Looks promising. It sure is looking like the -PNA my be taking hold and models are just now beginning to reflect this. Colder runs ahead?

  20. schmit44 says:

    12/15/2015 Oregon (All) Temperature Summary

    Warmest:
    High:55 at Gold Beach (US 1( 60 ft)
    Low: 46 at Port Orford(0 ft) & CW9654 Canby(158 ft)

    Coldest:
    High:17 at HOWARD Mt Howard(8150 ft)
    Low: -6 at DIMLKE (4726 ft )

    Largest Diurnal Change: 42 degrees
    DIMLKE (36/-6 ) (4726 ft )

    Heaviest Rainfall:
    0.75″ at SIGNAL TREE(3294ft)
    0.57″ at HOYT CREEK(5445ft)
    0.57″ at GREEN MOUNTAIN(3064ft)

  21. paulbeugene says:

    Euro shifting precip max to north valley for the next 5 days (4.5″ PDX). Hopefully no coffins floatin’ down Johnson Creek

  22. Mark bergal says:

    Exciting stuff. Any possibility of snow in the lowlands next two weeks?

  23. Jerry says:

    Mark, I live in Carson. Am I gonna get hit bad? I commute to Portland daily.

  24. Boring Oregon says:

    This may be a dumb question but why isn’t the Palmer snowfield open for skiing?

    • Mark Nelsen says:

      It’s in the high winds, rime, and fog during all the storms. Only good in winter when it’s calm and sunny

    • sds says:

      Mark is right–TL doesn’t even run the Mile in bad weather. Trust me (I’ve been patrolling there since ’67) it’s no fun skiing if you can’t see your hand in front of your face in a howling blizzard white out!

    • Dave in South Salem (500') says:

      At this rate there will be plenty of snow to ski on there this summer.

  25. Joshua Downtown PDX says:

    The streak of days with precipitation continues! .04″ at PDX. As things look now, we might go the entire month of December without a dry day. Awesome!

  26. Jason Hougak says:

    For those who missed it on the previous blog post

  27. Jason Hougak says:

    WINTER ROCKS!!!!

  28. Boring Oregon says:

    1.

%d bloggers like this: