Swift weather shift to wrap up the week

Weather

PORTLAND, Ore. (KOIN) — We are escaping the heat for a few days as a shift in the weather pattern shows up to wrap up the week. We will notice that happening today, but the full effect will happen Friday and into the weekend.

Today is the day where the temperatures shift to about average in the lower 80s. We will wake up with morning temperatures around 60 degrees. Lingering wildfire smoke may be hanging around in the morning hours after the transportation of smoke up to the north Wednesday. A gentle wind to start the day and a stronger wind east of the Cascades by the afternoon. The Oregon Coast starts the day with a light breeze off the Pacific Ocean with temperatures in the 50s. There is still that stubborn pocket of heat through the Lower Columbia Basin today, but improvements are coming Friday.

If you cycle to the second graphic you will have an idea of the afternoon temperatures and the wind. The complete cooldown isn’t quite here, but you will notice that it isn’t as warm in the afternoon for the Willamette Valley. Especially those of you to the south where temperatures may actually be closer to 80. The cooler air seems to find a way through the coast range there, but not as strongly up near the Columbia River. It will be windy from Hood River to Pendleton, with a west breeze kicking into the 20 mph range. Temperatures around may hold under 90 degrees today. The intense heat will more be north across the state line in Washington. More clouds east of the Cascades as thunderstorms may also develop for you today (like most days this week).

The thunderstorm potential will be greatest from Klamath county up through Umatilla County and points east. This is where the Storm Prediction Center (SPC), has labeled a large chunk of central and eastern Oregon under a marginal risk for severe storms. Expect cells with heavy rain, frequent lightning, and gusty conditions this afternoon in this part of the state. We may even get some hail out of this. We had a severe thunderstorm warning on Monday, we may have another today. I do not expect any thunderstorms west of the Cascades at this time. Our chance for rain will arrive Friday.

The storms will likely develop and get guided to the northeast. You can see the jet stream in the graphic below, which if you follow the orange and green stretch on the left, that is where the wind is the strongest today. That is going to help with the development of storms and it is what is also allowing for some of these storms to have a little more punch to them. That trough continues to move east through the day, taking the threat for thunderstorms over Idaho too. There is another disturbance on deck for Friday, which is separate from the system today. That will have more of a traditional rain and cooling effect. We are one day closer.

Here is a look at some of the development of showers later in the day today. This is a weather model that is depicting a couple of larger cells from Klamath County up through northern Harney County. The mountains over in Idaho are going to be creating some powerful cells, too. These will generate more lightning, leading to the potential for more small wildfires developing. You’ll notice a small patch of blue starting to pick up on the Oregon Coast this evening. Clouds increasing through the day and eventually a chance for some rain late at night for the coast.

That incoming onshore flow and the change of the wind pattern, well that is going to definitely clear out a lot of the smoke by late tonight. Check out the gradient the weather model is projecting by Thursday night between little smoke to thicker smoke. The mountains create a bit of a barrier and that smoke will hang around for those in central and eastern Oregon. We also saw with the jet stream graphic above, that the wind is going to be running from the southwest to the northeast earlier in the day, continuing to pump the smoke into central and eastern Oregon.

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