Tonight should be the coldest night so far this season. You can see that frost will be a bit earlier than normal for most places on this graphic. The text is quite small on this one, so click on it to get a larger view. The data comes from Oregon Climate Service and is from the 1971-2000 30-year average. As I recall from WAY back in the 90s, the frost dates used to be a bit earlier. I thought Hillsboro used to be in late October and PDX was more like November 8th or 2nd, or something along those lines.
Not a whole lot to talk about tonight. A surge of very dry air has moved south, out of Canada and into Eastern Washington and Northeast Oregon. Dewpoints crashed into the teens in E. Washington during the day with a gusty north and northeast wind. That very dry air just nicked The Dalles late this afternoon. Notice the "moist" west wind stopped for an hour or so before resuming. Dewpoint dropped at the same time. With a switch to light easterly flow tonight and tomorrow, I think we'll see dewpoints drop some here west of the Cascades tomorrow. Maybe a bit closer to 30 instead of 40. This should keep fog away the next two nights.
We left rain out of the 7 day forecast since there was no one specific system that is forecast by all models to move through the Pacific Northwest. But definitely close calls on Tuesday and/or Thursday/Friday. We'll see. Other than that the weather looks very slow. Rob Martin, our morning meteorologist may post a bit next week, so treat him like family! Mark Nelsen