PORTLAND, Ore ( KOIN) – Our first week of May is going to be a true spring roller coaster with temperatures reflecting four different months. Monday will feel like May, Wednesday will feel like April, Thursday will feel like June and then there is Friday, which will feel like the end of July!
Talk about a spread in afternoon temperatures over the course of five to seven days. The temperature trend looks a bit confused, with a 20-degree difference between Wednesday and Saturday. You will need to tap into a few different seasons’ worth of outfits this week. The thing about reaching summer temperatures in spring is they are usually short-lived and overnight temperatures typically still cool down enough to keep our confines from overheating.
Why the sudden warmth? We will cut off the colder air from the Gulf of Alaska lows and turn our onshore flow to offshore flow by the time we reach Friday. It’ll be the warm air at the surface that builds up from the southwest which is enough to crank our temperatures in the Willamette Valley.
In fact, that heat will stretch all the way up to British Columbia, leaving the west coast well above average. When that heat moves in, we will also shift the wind so it is cranking out of the east. It will be warm, dry and at times breezy. We may have a few days where we have to worry about fires.
Before we reach that heat, we have three days of near-average temperatures. It will be a few ticks over on Tuesday and a few ticks under on Wednesday.
An update to the system that is moving in for your Monday evening, it is on pace to reach Portland this evening. This may bring in a few scattered showers for the valley somewhere around 7 p.m. and that chance for showers will continue into the night. If we have measurable rain Monday evening, that will put us at four days in a row of rain to start the month. We haven’t had much rain over the last 30-45 days, so this stretch is helpful.