Good Monday morning! Here’s your Weekly Weather Briefing for September 14, 2020.

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Weak disturbance passage allows for potential for some air quality improvement today however high pressure is expected to rebound for most of the remainder of the workweek, thus air quality concerns are expected to linger into at least Friday. Low pressure moves in Friday and allows for unsettled weekend conditions allowing air quality

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improvements.

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This is a satellite image from Sunday afternoon. The red dots on this depict continued fire activity. A lot of smoke across the Northwest. Weak weather disturbances will try to thin out smoke a bit from west to east.

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A fire and smoke combination map. All of the red to purple color symbols indicate unhealthy to hazardous air quality as of Sunday evening. Smoke aloft is wrapping around an area of low pressure in the eastern Pacific. This low will shift inland at the end of the week.

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Air quality as of Sunday night was unhealthy to hazardous.

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The main weather related concern will be for the movement of smoke, or lack of movement. Air quality will be an ongoing issue through much of the week. It’s possible that some minor improvements to air quality will be seen early this week in eastern Washington near the Cascade mountains. However, longer range smoke models indicate

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the possibility for more smoke moving up across the region by mid week. There is higher uncertainty for what the air quality will be like at mid week. Confidence is high for improvements to air quality after Friday when the low pressure trough moves across. This will come with the potential for thunderstorms though for Friday afternoon.

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This is one depiction of how smoke concentrations will evolve today. Increased westerly flow should displace thicker smoke away from the Cascades to the east.

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By Tuesday, we are expecting improvements near the Cascades in eastern Washington; although, it looks to be a general thinning of smoke rather than a cleans of the atmosphere. Flow aloft then turns more southerly for Wednesday and Thursday and could bring up additional smoke from fires burning in Oregon.

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Very light rain or sprinkles will be possible Monday night into Tuesday. Not much if any actual precipitation is expected to measure.

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Best chances for showers and thunderstorms this week will be on Friday. Showers with embedded thunderstorms will continue into Saturday, and then generally drying back out for Sunday into early next week.

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Best chances for rain with showers Friday into the weekend will be across the mountains. Some spots may see wetting rains of at least a tenth of an inch of accumulation. Although rainfall will be a welcome sight for fires and to improve air quality, heavy bursts of rain from thunderstorms could be a concern on burn scars.

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Temperatures are expected to warm a bit into the 80s over eastern Washington and then cool into the weekend.

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Similar temperature trends are expected over the Idaho Panhandle.

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