Saturday, September 18th, 4:00 A.M.
As I type this discussion around 4:00 A.M., moderate to heavy rain is passing through northwest Oregon and southwest Washington. A strong cold front & atmospheric river have been working together to generate quite the soaker overnight and early this morning. The cold front will continue to advance to the southeast, which will cause steady rain to transition to scattered showers later this morning. Cooler air moving in above us will destabilize our air, which could lead to heavier downpours, small hail and even some isolated thunderstorms today. You’ll also catch some sunbreaks in between the showers. It’s going to be much cooler this afternoon, with highs in the metro area only reaching the mid to upper 60s.
Showery conditions will carry into Sunday, but coverage should diminish. An isolated storm can’t be ruled out either. Toward the end of the day, we should gradually dry out with highs reaching the mid 60s. After this soaking rain, we will be much more susceptible to morning fog in the valleys due to wet surfaces. I suspect we’ll see some low clouds and fog to kick off our Monday before sunshine returns. Temperatures will hit about 70 degrees Monday afternoon, and probably closer to 80 degrees Tuesday as high pressure builds in.
A weak system looks like it will force the high pressure system eastward on Wednesday, bringing more cloud cover and slightly cooler weather. Some of our models have been hinting at shower chances Wednesday, but that chance seems low (so we’re leaving it out of the 7 day forecast for now). Most signs point to another warming trend mid to late week.
Enjoy the wet weather this weekend!