Quick Morning Update

Everything proceeding according to plan, although heavier than expected precipitation brought the sticking snow level a little lower than I would have thought.  Still lots of heavy showers passing through the rest of the day, but now most sticking will be well above 1,000′ and partially melt between those showers.  Mine is slowly melting here at 1,000′.

All the rest of the forecast info on the previous post still applies, so I won’t rehash it until this afternoon when I’m at work.

850mb temp was -6.5 deg over Salem this morning and with heavy showers that was enough to bring sticking snow well down into the hills.  The air mass temp cools maybe 2 more degrees in the next 24 hours.

Two things I notice on maps/models this morning:

1.  Lighter or very little precipitation after sunset this evening all through tomorrow; could be less snow at/above 1,000′ then we saw this morning?  Check out the 2 different 24 hour snowfall forecasts from the WRF-GFS and our own RPM.  I’m really surprised our 4km RPM shows nothing over the higher hills in the Valley.  This tells me it’s a lack of precipitation and not an issue of “is it cold enough”.

2.  Tuesday morning is going to be a close call here in Portland.  It could be a significant late season wet snowstorm in the central/eastern Gorge.

And for fun, here’s the 12z GFS ensemble 850mb chart:

 

Chief Meteorologist Mark Nelsen

24 Responses to Quick Morning Update

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

    Temperature is dropping fairly fast here once again, back down to 36, after a high of 38 today.

  2. Mat the Salmon Killer says:

    Okay Mark, were all ready for a new and positively leaning towards snow post. Give us good news buddy.

  3. It’s 45.7F and partly sunny here next to the Clackamas TC

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

    Still falling as all snow here, although its too warm to stick, still sitting at 36.

  5. …3 inches on the ground, been snowing all day, power has been out since the middle of the night….sure is pretty though!

  6. lauriesylvan says:

    Yuck. Snowing and I have to go out to work. Not liking this for late February, when we should be having some spring sneak-peeks! Good evening for staying inside and watching ‘The Help,’ in preparation for the Oscars.

  7. Karl Bonner says:

    So the Tuesday rain/snow event WILL have a more traditional winter touch to it, with east wind and easier snow accumulation in the Gorge than in the Metro? I was thinking we were past that time of year, and from here on out the Gorge would have no cold-air advantage. Who would have guessed I’d end up being wrong?

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

    Moderate snow coming down here once again, 36. I really don’t see PDX making it to 48 today.

  9. Garron Beaverton says:

    THERE IS ANOTHER SYSTEM DROPPING DOWN FROM
    THE NORTH ON SUNDAY…BUT ITS NORTHERLY AND DRIER TRAJECTORY
    INDICATES SNOW ACCUMULATIONS WILL BE MUCH LESS THAN THOSE TODAY.
    HOWEVER…SNOW LEVELS WILL BE A BIT LOWER AND WE WILL SEE ANOTHER
    ROUND OF LIGHT SPOTTY SNOW CLOSER TO THE VALLEY FLOOR.

    Just a bit more moisture than expected may make things way more interesting than today, both tomorrow and Wed.!

  10. Positioning for Tuesday’s system would be great 45-60 days ago, but at the end of February I still don’t see it as being too threatening. Worst case scenario is snow on the ground for a few hours before it all melts away.

    Extended range WRF-GFS cross-section still says PDX avoids a ‘snowstorm’… will be interesting to see what it looks like once it gets inside the window of the shorter range charts.
    http://www.atmos.washington.edu/mm5rt/rt/load.cgi?latest+YYYYMMDDHH/images_d2/kpdx.x.th.gif+text+12%20km%20Portland,OR%2045.59N,122.59W

  11. This weekend is going almost exactly as predicted. When 850 MB temps finally get cold enough to make things interesting at the valley floor the moisture will be gone 😦

  12. Garron Beaverton says:

    It looked like a closer call this morning too. Will have to monitor the tower temps for Tuesday.

  13. Ryan says:

    Why in the central/eastern gorge, Mark? I thought this wasn’t an east wind thing. Can you explain or is tuesday too far away at this point?

    • Mark Nelsen says:

      That’s this weekend. This weekend is not an easterly wind type event; strong west wind and onshore flow right now. But Tuesday could be in the morning if the low is far enough south.

  14. This from Govt Camp…

    New Snow: 6 in.
    Roadside Snow: 37 in.
    Comments: Very high gusting winds and low visibility conditions throughout area. Use extreme caution throughout area.
    Last Updated: 02/25/2012 10:02 am

  15. bgb41 says:

    Looks like just a minor event.

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