Saturday Evening Update: 4:15pm

Here are the graphics I’m using for the evening show…I’m working tonight since I was already scheduled, not due to “SNOWPOCALYPSE 2012: THE REBIRTH” coverage.  I’m just kidding, we don’t have crazy out-of-control weather coverage tonight.  But some good pictures from the Cascades and Coast Range.

Today worked out pretty well, temps were within a few degrees of 40 most of the day; officially a high of 44 so far at PDX.  The showers were quite intense this morning, but there is a weakening trend since around 2pm on the radar.  Most likely we’ll see about half of the radar echoes disappear with the loss of daytime “heating” after 6pm too.  

Take a look at precipitation forecasts for Portland from several models, these are from 4am Sunday through Sunday evening when it dries out:

12z NAM: .07″
12z RPM: .08″
18z RPM: .04″
12z GFS: .09″
18z GFS: .05-.18″ depending on whether you use TTD or PDX.

If you want snow in the lowlands, that’s the main weather factor working against you the next 24 hours.  For this reason, I scaled back the snow totals even in the hills as you see in the graphics above.  I would be surprised to see more than a trace of snow officially out at the Portland forecast office.

Monday should be a great day with sunshine the entire day due to cool and dry air filtering in from the north.  Not an arctic blast, but a late February chill in the air.

 Tuesday is still really up in the air forecast wise.  If we get solid precipitation rushing in here quickly in the morning, we could see snow in the air everywhere and sticking even in some spots.  If it comes in slowly (like 11am or later) or is very light with a splitting trough, just a cold rain.  Something to keep an eye on.

If we don’t get anything on Tuesday, most likely we are done with a chance for sticking snow at the lowest elevations for the year.  Wednesday has onshore flow type showers like today except the airmass isn’t as cold, then slightly warmer temps later in the week with no real cold troughs (-6 or below at 850mb) showing up in the long range maps.

Chief Meteorologist Mark Nelsen

33 Responses to Saturday Evening Update: 4:15pm

  1. Cliff Gavic 1,100 ft says:

    Additional 2″ o/night. So far. 3″

  2. Andrew (Portland....Sylvan Highlands ~800 feet) says:

    Radar seems to be filling in nicely. PDX has dropped a degree to 37 as well.

  3. Andrew (Portland....Sylvan Highlands ~800 feet) says:

    Some more light snow coming down here once again this morning.

  4. Austin-Felida says:

    how is the gorge going to look on tuesday morning?

  5. bgb41 says:

    2/25/2012 Oregon (All) Temperature Summary

    Warmest:
    High:52 at DW9392 Bay City( 84 ft) & Rome (4049ft)
    Low: 42 at DW9392 Bay City(84 ft)

    Coldest:
    High:16 at ALAKES Haines(7979 ft)
    Low: 0 at ALAKES Haines (7979 ft )

    Largest Diurnal Change: 29 degrees
    Bly Mountain (Or (31/2 ) (4920 ft )

    Heaviest Rainfall:
    1.02″ at LOCKS(128ft)

  6. Andrew (Portland....Sylvan Highlands ~800 feet) says:

    Snowing and 34 here.

  7. So that wad of clouds to our west is just gonna slide down the coast and not give us any more precip tonite? Huh? What am I not seeing here?

    • Brandan-Damascus(675ft) says:

      Looks like both the Base 50 and Composite radar returns are starting to fill in as well. Anyhow it’s better when you don’t expect it.

      Btw half inch between 630 and 8 this morning here. Down the hill 100′ had not a trace.

  8. 2.75″ of snow here today. Currently cloudy and 31. Mid-week still looks decent for snow up here. If I get a good snowfall with that then I will pretty much be ready for spring.

  9. W7ENK says:

    Looks like it’s pretty much over with… NWS has begun dismantling their WWAs.

    http://inws.wrh.noaa.gov/weather/alertinfo/5033113

  10. Mark Nelsen says:

    The 00z GFS and our RPM say “no snow” in the lowlands Tuesday; looks like the low is a little farther north and we get a decent southeast wind above the surface, plus the precipitation holds off until about midday.

  11. B1900 Pilot says:

    Attended a great seminar on radar for pilots given by Clinton Rockey from NWS Portland here in Puyallup. Finally learned how to use velocity to determine wind direction and speed in the lower levels. Thanks Clinton!

  12. …4 inches, still snow showers going on, power’s been out since 2am, occasionally windy with blowing snow, running on generator and propane, …finally, real winter!!!…

  13. Karl Bonner says:

    What about the possibility of river-level sticking snow in the Gorge on Tuesday? With dry subarctic air in place and if the incoming storm isn’t too wimpy, you get a dry east wind, possibly with some evaporational cooling as the precip starts. Provided the precip starts in the Gorge before the wind turns westerly, we’d probably have a brief bout of sticking snow.

    HOWEVER, given that it’s the end of February, I seriously doubt that sufficiently cold air would hang around for very long before getting pushed out by a “mild” (i.e. slightly less cold) west wind. Inversion season is pretty much over, and with it goes the chances for cold air to get stuck in the Central/East Gorge for significant amounts of time. So I think any sticking would be brief before sticking snow levels rise to 1000-1500′ or whatever. Perhaps the existence of snow cover already on the ground will make it easier for snow to continue sticking as the airmass begins to moderate, but I bet such an effect would be pretty minor in magnitude before it just gets too warm and whatever snow did manage to stick melts away at the lowest elevations (while hanging around on the high hills).

  14. near POWELL BUTTE its 36 and dropping fast and some nice clouds coming in which might mean=snow:))

  15. Andrew (Portland....Sylvan Highlands ~800 feet) says:

    Already down to 33 here, looks like some light shower activity is making its way into the metro area now.

  16. W7ENK says:

    Lack of moisture?? Awww, too bad.

  17. FrankC says:

    Mark writes: “If we don’t get anything on Tuesday, most likely we are done with a chance for sticking snow at the lowest elevations for the year. ”
    For the year? Wow…so no snow in November or December of this year? I know he’s pretty good at forecasting, but this is amazing…

    Yeah I know what he meant, just busting his chops a bit all in fun. Really do appreciate how accurate he tends to be

  18. Mat the Salmon Killer says:

    Almost looks as though the showers are enhancing ahead of that next low coming in which also looks good with the trajectory it’s currently in. hmmm. . . . . . .

  19. pappoose in scappoose says:

    I really like to see snow in the air everywhere, and even sticking in some spots!

  20. *BoringOregon* says:

    Hey mark, that’s what you keep on saying. But look what happen’s lol?

  21. So an other TRACE is possible right!

  22. alohabb says:

    I am ready for Spring! Bring on the warm temps, BBQ’s and beer!

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