Long heat wave ends Monday, wildfire smoke begins to lift

Long heat wave ends Monday, wildfire smoke begins to lift

PORTLAND, Ore. (KOIN) – What a stretch of heat we just endured, with 6 days topping 90 degrees — and two of those days over 100. That was the longest period of heat that we’ve had to deal with this summer.

It didn’t reach the extreme levels of the June heat wave, but it sure stuck around. Monday, we should finally stay below that mark, with highs in the mid 80s around the Willamette Valley. When you set off in the morning, temperatures will be in the 60s, at least four to five degrees cooler than Sunday morning.

The cooler northwest air is going to rush in by the evening hours, bringing temperatures down quicker than the last 6 days. Most days we’ve seen our warmest temperature in the dinnertime window, but Monday it will likely be warmest around the afternoon to late afternoon. Notice in the temperature Futurecast that some communities are already dipping below 80 by the time 4 p.m. comes along. That is the cooler air that is moving in, which will also generate some clouds for us by the commute home.

Temperatures still warm out near Pendleton, but we should have temperatures dropping around The Dalles and Madras on Monday compared to what was going on Sunday. There was a lot of triple-digit temperatures on Sunday, we should avoid that in the forecast Monday afternoon. Temperatures are not nearly as warm out at the coast to start the week.

The weather pattern graphic will show us what is going on aloft, and what it’s depicting is that dip in the jet stream pushing down from the northwest on Monday. We are right between the warm air from the weekend and the cool air that moves in Tuesday.

That is exactly how the day is going to play out, with some warm moments and cool (relative) moments. The important part is that the massive ridge is finally starting to flatten out, hopefully allowing for conditions to stay near average even behind this disturbance that is moving in over the next 24 hours.

The cooler marine air and the shift in the wind is allowing for the wildfire smoke to clear out of the valley. There may still be some hazy conditions east of the Cascades to start the morning, but it will also improve for areas like The Dalles by the afternoon and evening hours.

If you cycle through the high-level smoke forecast, you will pick up on a few streams from the active fires that are burning in the Cascades on Monday. That is going to impact locations closer to the source or directly to the east. It doesn’t quite disperse across the state at this time. If there is a location that will be more vulnerable to the smoke all day, it will be Baker City. Wildfire smoke does stick around for the far east side and southeast side of the state to start the week.

I want to also stress that there may be some locations that find a little rain Monday before we wrap up our start to the work week. As a cold front approaches, it may stir up a few showers for the Oregon coast by the evening, with a chance for some showers developing in Clackamas County or Marion County foothills late Monday.

Measurable rain is going to be tough to come by in Portland, but there is a chance for a drop or two to come passing through late Monday into Tuesday morning. We could use that rain and we are hoping for it, but the moisture is limited. As this system moves in late Monday, the wind is going to increase east of the Cascades. That means even earlier in the day, the wind may be gusty for some areas. We should see the relative humidity increase, which will help the overall conditions for wildfires, but the wind may be gusty.



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