8pm Friday…

The big weekend is here folks! I’m at work, and will be part of the weekend, but I know lots of you have plans far away from any job. Maybe headed to (or already at) the ocean beaches, Cascades, Gorge, or Central Oregon?

The forecast is easy this year…all sunshine all weekend from the Coast Range to the Idaho border tomorrow through Monday. Just a few thin high clouds at times. A thin marine layer may return to the beaches Sunday/Monday for areas of low clouds/fog, but otherwise expect abundant sunshine even out there.

Strong high pressure just offshore moves directly overhead at the surface AND high up in the atmosphere the next few days. High pressure = sinking air = mainly sunny & warm. Check out the upper-level ridge over us by Monday; this is a very warm to hot summer weather pattern along the West Coast

Temperatures at 850mb (about 4,000′) soar from around 48 degrees this afternoon, to around 65 by Monday/Tuesday afternoons. That’s about +4 celsius to +18-20 by Tuesday afternoon. That alone will push our high temperatures from around 80 tomorrow to 90 Tuesday. Those temperatures are very dependent on wind direction down here at sea level. Tomorrow will be the one day we get an easterly wind through the Gorge and over the Cascades. Then it’s back to flat or weak onshore flow Sunday/Monday. So even though upper-level temperatures climb Sunday and Monday, we didn’t go wild with high temperatures.

Tuesday is a bit more interesting as a thermal trough (and easterly flow) tries to form west of the Cascades briefly. If that occurs, we could end up INTO the 90s instead of just 90 that day. TBD.

For now, we’re going for these numbers this weekend

If these numbers are correct, IT WILL BE THE WARMEST MEMORIAL DAY WEEKEND IN 26 YEARS IN PORTLAND! That’s if you take the 3 day average of the high temperatures. You can see how it compares with some of the other warmest holiday weekends in the past 40 years. Probably just a little warmer than 2017, just four years ago.

I remember 1983…the earliest we’ve ever hit 100 in Portland AND the only 100 degree day experienced at PDX in the month of May. That was the Saturday. What I remember about that year is the cool/cloudy/drippy weather just two days later with a big marine layer and showers. Quite a swing from 100 to 63 (Saturday to Monday).

If you are headed to the Oregon Coast, or already there, this is what we expect:

And some real summer-like camping in the Cascades too, that doesn’t show up very often for Memorial Day Weekend

As for rain…the next POSSIBLE chance is next Thursday or Friday as the upper-level ridge flattens. A few disturbances could swing by and give us showers or rain.

This will finish off the driest spring on record in Portland, but I’ll save all those dry weather numbers for a Sunday or Monday blog post.

Enjoy your weekend and stay safe!

Chief Meteorologist Mark Nelsen

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