PORTLAND, Ore. (KOIN) — It’s time that we switch over to some cooler weather for our first week of May. We’ve experienced some above-average temperatures this week, especially Wednesday, but we are going to settle down to wrap up the week.
We’ll notice the cooler air in Portland today with temperatures in the lower to mid-50s in the morning. That major difference is going to come in the afternoon as those temperatures decide to stay cooler and not soar into the upper 70s. The cooler air won’t quite make it over to areas of Pendleton today, but it will arrive by Friday. When you’re out and about in the afternoon, highs likely reaching the mid to potentially the upper 60s.
Weather models are likely underplaying the temperatures today. The timing of the system is to arrive later in the afternoon and with a moderate breeze running out of the southwest, you can expect temperatures to be around average. Pendleton probably pushing 80 degrees for the second day in a row.
Futurecast is pushing moisture in by the morning hours in parts of Washington, but the rain chance doesn’t pick up around the valley until later in the day. There is a higher chance for rain to move through the Willamette Valley by the evening hours and this is when temperatures will start to cool down as well. Behind this disturbance, we have cooler air and more rain coming, as a trough continues to shift to the east through the end of the week and into the weekend.
Do you need a rain jacket today? Well, it’s worth having in the afternoon and evening if you don’t want to battle any rain. If you’re alright with a passing shower that will likely be light, then you’re good to go in the valley. You may just want one for the slightly cooler temperature.
Although the showers that are going to be moving in aren’t going to be consistent, we should keep the clouds in the forecast today. There will be breaks later at night, but that will likely come after our sunset on Thursday. Sunshine out there for your folks in Umatilla County. If you want to dodge the clouds over in Portland, you may want to take a drive to the east. You’ll also get some great window-down weather as you reach the warmer temperatures today.
Let’s talk about the rain totals for the day as we track through this first weak wave of energy. Scant amounts around the Willamette Valley this afternoon. There isn’t much to really take in on Thursday outside of maybe some spots along the coast picking up around .15 inches of rain. Rain totals start to stack up by Friday and into the weekend. This is going to be an appetizer to the overall picture for the span of Thursday to Sunday.
We look to Friday for more support and organization to our cool and showery weather. The trough is tilted slightly in a negative orientation on Friday, which may spell a few thunderstorms east of the Cascades. Most of that cool air comes in and that should keep conditions slightly unsettled, allowing for more rain too.
I would also expect the temperatures to drop a good 5 more degrees in the afternoon high from Thursday to Friday. I would suggest a rain jacket in the car or the rain gear for the bike by Friday.