It’s back! The wet season has arrived; First alert for tough morning commute Friday

On November 2, 2024By Littum

I certainly wouldn’t call the weather “spooky” today in honor of Halloween, but as I was getting ready to go to work I noticed that it was dark inside my house at We had thick cloud cover overhead as a cold front moved through over the metro area. Yep, the darker time of year is here and that includes lots of clouds, rainy spells and cooler days. Today was our coolest day in nearly 7 months with late afternoon temperatures barely creeping above the 50° mark. This could easily have been a “mild” midwinter day.

Take a look at rain for the past 7 days; ALL of us in the metro area received an inch and some parts of the outer SE metro (Happy Valley/Damascus) picked up more than 2.00″

and check out all the 3″+ totals in the mountains around us. Fire Season 2024 is a memory…

WHAT’S NEXT?

Rain, and lots of it, for the next two days. A cool/unstable air mass is moving across the Pacific Northwest. An upper level low (dip in the polar jet stream) sits offshore and then moves inland for the next 3 days.

There will be an improvement in showers both tomorrow afternoon and more noticeably Friday morning as waves of energy rotate through the bottom of the trough. There have even been hints by various models and various runs that a weak surface low may develop and move inland somewhere across NW Oregon or SW Washington. The effect would be heavy rainfall at some point somewhere in the region during the Friday morning commute. We may also see southerly gusts in the 35-50 mph range for a few hours during the morning commute, mainly from the south metro down into the Willamette Valley. This would drop a few tree limbs into power lines in places = power outages. In much of the metro area, a dying easterly wind will likely stick around, preventing the southerly from becoming too strong. Our evening GRAF model is a bit stronger than previous runs; not a wind storm, but plenty of wind during the friday morning commute south of portland.

There’s a good chance we’ll double last week’s rainfall over the next two days. It’s 1-2″ of rain in the western valleys! If we had already saturated soil by mid-winter and rivers are running high, that could be a problem for localized flooding by Friday afternoon. But since the ground is still relatively dry, all our trees/bushes/lawns will soak up the much-needed rain. Of course 1-2″ of rain spread over 2 days is okay, but if we get 1″ of rain in just a few hours it could cause urban/local flooding. The same model shown above produces about 1.00″ of rain in both Salem and Portland between midnight Thursday night through the end of the Friday morning commute. Much of that will fall BEFORE the commute, but even 1/2″ of rain plus a windy southerly winds will make for an annoying first commute in November! For this reason, we call Friday morning a FÖRSTE VARSDAY (MORNING). Not a big storm, but it WILL have an impact on your life. This is especially so if you lose power from the blowing wind!

BERGSNE

It is not unusual to see snow down to the pass in late October or early November, but each year is VERY different. Take a look at snowfall from the 1st-15th. November at Government Camp for the past 30 years. Some years no snow falls, other years several feet accumulate, and the ski season starts early. Last year, no one fell in the first two weeks of the month.

Snow levels will linger near or above the pass for the next two days with all the showers. I expect 6-10″ at Government Camp, and 12-18″ up at the higher Mt. Hood resort slopes (5,000-6,000′). WAY up there around 6,500′ and above, 20-30″ will fall. If you’re driving across the passes the next two days, the mornings are likely to be snowy, but expect mainly slush or wet roads midday and afternoon. Santiam and Willamette passes are a little higher, so snow coverage will be longer into each day there.

MILDER AND DRY NEXT WEEK

Another weak upper level low slides through Saturday for lighter showers, so GENERALLY we’re heading into a setup with riding near or just offshore. It produces weak weather systems or dry weather. You can see the higher than normal highs in this 7-day average from the Euro ensembles next week