The Weekend Is Here!

Yuck!  Check out this X-Section from the UW WRF-GFS.  Time goes from right to left…from this evening to Monday evening.

The green areas indicated a saturated atmosphere (generally fog or cloud cover).  Note that from later tonight to at least Monday evening the airmass overhead is saturated from the surface to 10,000′?  That says November gloom ahead.  Get out the anti-SAD lamps folks!  It’s a warm front coming through tomorrow with the freezing level jumping well above 10,000′.

Okay, let’s talk about that previous post.  Wasn’t that a fun forecasting exercise?  It’s tough to actually write down a forecast, then have to stick with it through various model runs…I see a few of you even tweaked it a bit after the 00z GFS came out.    My only mistake is that we should have done it 24 hours ago when long range models were colder.

Here’s my forecast:

THURSDAY:  40/45  Light rain
FRIDAY: 35/45  Showers (that low is probably too low, but that’s on the 7 Day.
SATURDAY: 35/43 Turning partly cloudy, a shower?

The GFS is a bit warmer than this…it would be in the mid-upper 40s Saturday.

So there were rumors floating around MediaLand this afternoon of a possible arctic blast or snow to sea level coming up next week.    It’s pretty obvious that it isn’t cold enough for either through at least 8 days from now (next Saturday/Sunday).  The new 00z ECMWF just came in and is almost exactly like the 12z run.  We just turn cool and dry later Saturday and Sunday.  The 00z GFS was similar, except notably warmer.

To sum it up…as of now I still don’t see a decent chance for lowland snow or an arctic blast in the next 7-10 days.  But definitely colder with some good mountain snow.  With northerly flow forecast in the ECMWF (not GFS now), we have to keep a close eye on things though.

Chief Meteorologist Mark Nelsen

157 Responses to The Weekend Is Here!

  1. Danny inn Troutdale says:

    KPTV should have a forcast on the website or something where the bloggers come up with there own. I think that would be kind of cool :).

  2. Anthony Bertolo - Gresham 500' says:

    No snow flake in the forecast? Dang.

  3. W7ENK says:

    Mark, you’re flirting with the danger zone, showing that big purple trough dropping out of the North… 😆

    Saw your photo, too Antipex! The graphics intern mis-spelled your first name, tho. 😳

  4. PDX Weather Nut says:

    It’s only 48 degrees outside the house here but feels at least 10 degrees colder with the rain and damp weather.

  5. wendy-silverlake,WA says:

    LOWER COLUMBIA-WILLAPA HILLS-I-5 CORRIDOR IN COWLITZ COUNTY-
    INCLUDING THE CITIES OF…ST. HELENS…CLATSKANIE…CATHLAMET…
    WILLAPA…FRANCES…ELK MOUNTAIN…LONGVIEW…KELSO…CASTLE ROCK
    238 PM PST SAT NOV 13 2010

    .THURSDAY NIGHT…MOSTLY CLOUDY WITH A CHANCE OF SHOWERS. SNOW LEVEL 2000 FEET. LOWS 35 TO 40.
    .FRIDAY…MOSTLY CLOUDY WITH A CHANCE OF SHOWERS. SNOW LEVEL 2000 FEET. HIGHS 45 TO 50.
    .FRIDAY NIGHT…MOSTLY CLOUDY WITH A CHANCE OF SHOWERS. SNOW LEVEL 1500 FEET. LOWS 35 TO 40.
    .SATURDAY…MOSTLY CLOUDY WITH A CHANCE OF SHOWERS. SNOW LEVEL 1000 FEET. HIGHS 45 TO 50.

    So if I get busy and get the studs on, all chances of snow are off. But….if I’m not prepared it will probably snow….hmmmm….what to do!!!

  6. W7ENK says:

    There seems to be an awful lot of water coming out of the sky for the radar being so blank… o_O

  7. Yevpolo1990 says:

    I would not be surprised at all if 00z shows -15 850 temps over PDX..

  8. Max in Fairview says:

    Nice to see our first real chance of the cold stuff ( freezing temps/snow) could be coming before Thanksgiving! I foresee many changes to forecasts very soon.

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

    Get ready for the 7 days to change by tonight’s telecasts.

    I’ll check it once I get back home tonight. First I’m watching the Ducks game then heading out to see A Perfect Circle at the Showbox here in Seattle.

  10. Rob "Wrath" S.E. Portland says:

    It seems like momentum is building for a cold snap of some type. Modified? just through the Gorge? or a true arctic blast such as 18z suggests. We need 1-2 more days. I will say do not be surprised if some future model runs are absurdly cold.

    • Rob "Wrath" S.E. Portland says:

      If the 500mb pattern shapes up this way it is very possible we see something as the 18z advertises, or even colder.

    • Boydo3 500' North Albany says:

      Or revert back to milder. Hopefully this projected pattern turns out right!

  11. salivation time
    models continue snow flirt
    batten down hatches

  12. Danny in Troutdale says:

    Fewwww….. Meteostar didnt refresh when I looked at Troutdale. So I thought it was still showing warm since last. Glad!!!! Starting to get real interesting!!! 🙂

  13. stevied (North Portland) says:

    The Spokane NWS discussion this afternoon does talk about next weekend some…

    FRIDAY INTO THE WEEKEND…THE LONGWAVE PATTERN WILL HAVE SHIFTED FAR ENOUGH SOUTH…PLACING THE JET INTO OREGON…AND THE INLAND NW ON THE POLAR SIDE. THE AFOREMENTIONED NORTHERLY JET ACROSS NW CANADA WILL CONTINUE TO FEED SHORTWAVE ENERGY INTO THE LONGWAVE TROUGH ACTING TO “RELOAD THE GUN” SO TO SPEAK. IT WILL BE ANY ONE OF THESE WAVES WHICH ROUND THE BASE OF THE TROUGH AND EJECT INTO OUR VICINITY WHICH WILL BRING A CHANCE FOR SNOW TO ANY LOCATION. FOR THE MOST PART…SNOW LEVELS WILL BE ALONG MOST VALLEY FLOORS. ADDITIONALLY…THE ARCTIC BOUNDARY WILL ON OUR NORTHERN DOORSTEP AS EARLY AS SATURDAY…POSSIBLY SPILLING INTO THE INLAND NW SUNDAY. THIS IS SUPPORTED BY SOME GUIDANCE BUT HAS NOT BEEN VERY CONSISTENT RUN TO RUN SO CONFIDENCE REGARDING THE ARCTIC AIR INTRUSION AS WELL AS DETAILS WHEN/WHERE SNOW ARRIVES IS LOW. MY HIGHEST CONFIDENCE IS RELATED TO THE PROBABILITY OF BELOW NORMAL TEMPERATURES. /SB

  14. stevied (North Portland) says:

    brrrr… 18z run is a cold one. I need to see that kind of air within 180hr mark on the models to believe it’s a real possibility.

    Man,shows Spokane, WA with down to 507 thickness and -20c 850mb temps. Brrrr…

    http://wxweb.meteostar.com/sample/sample.shtml?text=ksff

    The Dalles gets to -14c… our friendly Gorge feeder.

  15. jory (Sandy) says:

    OK… At this point, when this upcoming week will become interesting? Yesterday, I heard Friday, the 19th. Now I’m seeing Saturday or Sunday. I have to go to Seattle on Friday, will I see snow, or Ice on or along I-5?

    • Jesse-Orchards says:

      Do you ever notice that posts like this never get responded to?

      Yeah.

    • Jory (Sandy) says:

      Yes, I have noticed that. Just wondering if I will need to put on my studs for Friday, or can I do it on Saturday, back home?

      I suspect one of the reason why these questions don’t get answered, is because the blog is getting frequent posts, so the questions that was asked, falls to far back from the top.

    • W7ENK says:

      I think it’s because things are still too uncertain, and no one wants to commit to a definite answer yet. If I knew, I’d say. If I had to make a guess, I’d say rain turning snow showers Friday evening, snow Saturday in Seattle, +24 hours for Portland. BUT, that is purely a speculative, uneducated guess, so take that for what it’s worth.

    • PDX Weather Nut says:

      Doesn’t look like it at the moment … just the usual cold rain

    • Ryan (Walnut Grove) says:

      Too early too say.

  16. Mike (Orchards 255') says:

    Similar Analog? Noticed the Nov 1985 pattern on here..

  17. Sarah in West Linn says:

    I love seeing maps like these. They’re so rare! Usually all the cold air spills into the nation’s midsection, cut off by the Rockies. I know the models often forget to factor in the Gorge, but they couldn’t have ignored the Rockies this time, too. (Could they?)

    • Anthony Bertolo - Gresham 500' says:

      The reason the cold is spilling onto our side is due to a couple reasons. First the upper atmosphere (500mb) continues to bring the air from up north. On top of that, what we need to get cold air is a low pressure system off the coast, to suck the cold air out toward the pacific. We have both of those things which is why models are forecasting cooler temps.

      But you are right, in general the models don’t do stellar with geography.

  18. Rob "Wrath" S.E. Portland says:

    What an incredible shift over the past 12-18 hours in models. There is decent agreement, but is this the final trend? Is this cold solution locked in? I want to say YES, but I want to see another day or so of runs like this.

  19. Anthony Bertolo - Gresham 500' says:

    Come on Mark, can you give us at least one flake on the 7 day? Just to feed our delusions?

  20. Rob "Wrath" S.E. Portland says:

    18z is an arctic blast for PDX, if not it is as close as you can get to being one.
    http://wxweb.meteostar.com/sample/sample.shtml?text=kttd

  21. Rob "Wrath" S.E. Portland says:

    18z is a MUCH better run especially in terms of jet/upper level support you can clearly see this. Also thicknesses/850mb temps and nice southwestward progression of the cold air. If there are any concerns about not being cold enough? The cold will be there…. Models aren’t going to be able to initialize or recognize it yet… In fact if the 500mb pattern and trough digs like this on future runs I think they could easily turn colder…

    • Anthony Bertolo - Gresham 500' says:

      The 500mb pattern is great, I agree with that. The models want to keep the cold air wrapped up just north of the low. If the low digs a tad further south, or the 00z has a similar 500mb forecast, I also agree lower atmosphere temps will go lower.

      The odd thing is that this run and the ECMWF are not too far off in terms of L placement and 500mb pattern, they are different in how cold the air will get though. I expect Mark to stick with the ECMWF though.

    • Rob "Wrath" S.E. Portland says:

      If 00z EURO trends like this….

  22. Anthony Bertolo - Gresham 500' says:

    Holy cow lala lands is awesome.

  23. Anthony Bertolo - Gresham 500' says:

    So what is gonna go down Saturday? We have heavier moisture with the 18z, temps are slightly warmer though. Right now it looks like cold rain, with snow down to 1000-1500′. The low is feeding off frigid air to the north, but unlike past runs, the real cold air doesn’t drift over the pacific, so it gives the air plenty of time and distance to moderate.

    Sunday on the other hand has great upper air dynamics, with cold enough temps and some moisture still to work with. That could be a snow scenario down to 500′ or even lower. The only issue is that it looks like Sunday is what Saturday was, as in, the ol’ GFS pushing back a day?

    • Yevpolo1990 says:

      just pushed a 1 day back, fine with me to be honest I wouldn’t mind since I got school on Monday 😉

  24. Yevpolo1990 says:

    Correct me if I am wrong, hours 174-192 show snow here all the way down to the valley…850 temps around -6/-7

  25. Yevpolo1990 says:

    THat low is really teasing us around 160-172…

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