The snow rumors are just getting going today, and they should be going crazy the next 2-3 days. A bit amusing since we have 3-4 days of beautiful sunshine ahead! I covered all that in the previous post, so let’s move on.
For those just checking in wanting the basics here you are:
- Our best chance of sticking snow to the lowest elevations (in the cities) this winter so far arrives Sunday and continues through Tuesday, possibly a bit longer.
- The possibility of an inch of snow in the city of Portland has increased a bit since last night…I give it a 50/50 at this time.
- Those of you in the hills (1,000’+) should get at least some snow, possibly quite a bit (6″+) during this period. First chance is probably Sunday morning…we’ll fine tune the timing later.
- Finally, the Cascades should see quite a bit of snow next week.
- As of now, I don’t see any “arctic blast” or major snow/ice storm, we’re talking the heavy, wet, 32 degree snow.
Okay, so what’s changed? The news snow-train has left the station…
The GFS has come into line with the ECMWF the past 24 hours, and all models seem to be in agreement for an “onshore flow” low elevation snow pattern. I hate these. This pattern has at least a light or even moderate southerly wind up the Valley the whole time, so some spots can get 2″ as a batch of showers moves through and other spots nothing. The new GFS was signficantly wetter Monday and Tuesday as well. It has been lowering upper-level heights the past few runs, thus the cooler temps.
Tuesday and beyond it’s quite the battle between cold air to the north and westerly flow pushing in from the west. For now, I don’t see a setup for an easterly-flow type snow situation, but only a shift south in the models would bring surface low pressure systems in to our south, possibly setting up a big snow event. Something to keep an eye on. I notice the 00z GFS ensembles are almost all a bit colder than the operational GFS Tuesday-Thursday. Could be a sign that the heights will be even a bit lower, along with those lows a bit farther south…we’ll see:
Anyway, COULD be fun times ahead, or we might just get some marginal snow Sunday-Monday. Of course even that will be far better than anything else we’ve seen lately.
Chief Meteorologist Mark Nelsen