Freezing weather Thursday in Portland weather forecast

PORTLAND, Ore. (KOIN) — Winter is coming to an end: cold mornings, the chance of snow, the threat of ice, it’s all about to end for quite a while.

With that, we are 11 days away from the first day of spring. The afternoon sun and passing showers will begin to encourage flowers to bloom as the angle of the sun increases afternoon temperatures. This is the time of year when winter begins to look more like a spring forecast. It was quite a build up to let you know that we have a cold winter morning ahead of us in Portland.

Cold air is coming in from the north on Wednesday. There will be a gusty easterly breeze bringing this cold air through the gorge into the Willamette Valley by Wednesday evening. You take into account that with clear skies you have the recipe for a freezing morning. Not only will it be cold around Portland, but surrounding valley communities outside of downtown will be even colder.

Check the frost forecast for the next two nights. We expect temperatures to reach the mid upper 20s tonight through Thursday. It’s cold enough for a hard freeze around the I-5 hallway by tomorrow morning. If you just planted something that would be sensitive to this type of cold air, you’ll want to cover it up or inside tonight.

It might seem like temperatures in the 20s aren’t a big deal for March, but that doesn’t happen often at this time of year. Looking at a 30-year average, a low morning temperature of 30 degrees or less has a five percent chance. For temperatures to reach 25 or lower, the percentage drops to 0.6%. Morning temperatures are expected to hover in the upper 30s for the second week of March. We are going to approach 10 to 15 degrees below average on Thursday morning. Winter jackets will come in handy the next few mornings (or late at night if your schedule calls for it).

Are we approaching our final freeze of the season?

We are approaching the average last date for a freeze in the Portland area. Most begin to see this last freezing temperature around March 19. It’s a month later when we start to see our final temperature of 36 degrees. You will notice that the last average 28 degree day is February 12, which we may end up seeing early tomorrow morning. It’s an average over time, so it’s not the ultimate law here. It has been years since we had some of these freezing temperatures until May. This gives April the freedom to have a few days that also fall into the 30s. This is useful information for those of you with green fingers.

The graph below does an appropriate job of displaying the transition from overnight cooler air to Thursday. Cooler air is represented by dark blue and purple shades. You can tell the high desert and those in eastern Oregon will tap into something colder than the Willamette Valley. We expect temperatures around Madras to be overnight tonight. Those in Baker City may have a lower morning in the single digits. This type of cold air will continue to retreat north over the next month, leaving our temperatures milder.

Here’s a general idea of ​​some of the early morning temperatures around the greater Portland metro area. If you’re in the outskirts, you can expect temperatures well into the 20s. It sure looks like areas in wine country will be the coldest in the morning. This is a good example of the cooler temperatures although not exactly in the dark shade of blue in the graph above. This is because this area is away from the city center and is sheltered from the wind.

The cloudcast has most locations clear of the clouds in the wee hours of the morning. You should wake up to frost on the cars and deceptive sunshine. A few clouds moving into areas of the western gorge and near the mountain cannot be ruled out.

Overall, winter is coming to an end, but we still have a few potholes to get through before we get there.

Dale D. Schrum