We’ve got a huge soaking on the way Wednesday! A very wet warm and cold frontal system is on our doorstep tonight. This will be by far the wettest storm this Fall both in terms of rainfall and mountain snow. I think our RPM model (above) is probably a bit wet, and notice the smoothing issue as mentioned in a previous post. When I read this I usually take that Hillsboro number and consider it to be a metro-wide rainfall. But 1.50-2.00″ is a real healthy rainfall.
Still looks like 18-24″ total up in the mountains that is here to stay; the result should be at least some minimal skiing this weekend on Mt. Hood.
Okay, so how are snow levels looking? I still feel a solid 1,500′ for most areas is good, but I’m sure some spots down around 1,000′ will see at least a dusting. Best chances for that are early Friday morning or Friday evening if a cluster of showers moves through. Sticking snow is still looking very unlikely at the lowest elevations.
That said, I bet at least 50% of us will see at least flakes mixed in at some point during the 18 hours Friday 5am-11pm.
A real chilly air mass, coldest so far this Fall by far, moves in late Friday and Saturday. IF we get good clearing either Friday night or Saturday night, we’ll be way down into the 20s.
As for that Saturday system? Looks slightly closer on the 00z runs compared to 00z last night. The 18z GFS was quite a bit closer to the coastline, but now it’s back to farther offshore.
This isn’t one of those situations where the cold air lingers, it’s back to southerly low-level flow by late Sunday or for sure Monday AM.
Next week looks very rainy and windy. The 00z GFS has some deep lows close by, and the GEM (Canadian) has them even closer. More weather action to come…
Chief Meteorologist Mark Nelsen
Posted by Mark Nelsen 
