On the 15th, the high of 99 at Burns set a daily record.
On the 16th, the high of 103 at Boise set a daily record. A record of 100 was set at Burns.
On the 17th, the high of 102 set a record for the date at Boise. Other record highs include 106 at Mountain Home and 99 at Baker City.
On the 18th, the 98 at Baker City tied the daily record.
On the 19th, the 97 at Twin Falls was a record for the date.
It was drier than normal nearly everywhere, but, as mentioned in the July summary, that’s actually normal.
Monsoon thunderstorms brought more wind than rain.
On the 15th, a thunderstorm near Andrews, Oregon broke off dead tree limbs and did other minor damage. At Little McCoy Creek in Harney County, a gust of 63 mph was measured by automated equipment.
On the 17th, a gust of 70 mph was measured by a spotter. A spotter in Fields, Oregon measured a sustained speed of 44 mph with a gust of 58 mph. A spotter in Fields measured a 54 mph gust which resulted in lost power. There were numerous other reports of gusts exceeding 50 mph.
— NWS Boise (@NWSBoise) August 17, 2020
— NWS Boise (@NWSBoise) August 18, 2020
On the 18th a spotter in Oreana reported half-inch diameter hail.
As usual, the seasonal upper level high pressure ridge over the southwest states was the main source of the heat. An occasional Pacific cold front provided some respite, but there was no significant cooling Until the end of the month.
Had the air been clear, it would have been even hotter. But widespread smoke from wildfires limited high temperatures on many days. Persistent southwest flow aloft transported the smoke from its California source.
Model forecast of the wildfire smoke for Thursday. Some improvement is expected with the frontal passage but overall the smoke will remain over the area. #idwx #orwx #wildfires pic.twitter.com/LsnXPcLR3X
— NWS Boise (@NWSBoise) August 20, 2020
#Smoke plumes from over 500 #wildfires in California and Oregon will continue the low visibility and poor #AirQuality through early next week. Over 750,000 acres have burned in California over the last week. #idwx #orwx pic.twitter.com/Z6i0yPxEUq
— NWS Boise (@NWSBoise) August 22, 2020
We couldn't get our camera out quick enough to capture this smoky sunset before it disappeared behind the clouds in Boise. Did anyone else get a good photo of the sunset tonight? #idwx #orwx pic.twitter.com/CBxBHysQBP
— NWS Boise (@NWSBoise) August 25, 2020
The monsoonal moisture brought high dewpoints to the region, which helped fuel afternoon and evening thunderstorms from August 24th through the 29th. Boise recorded the highest dewpoint since September 5th, 2013 on August 25th.
Does it feel "muggy"? Boise's dew point temperature (a measure of actual water vapor in the air) reached 65F at 743 PM MDT, the highest since Sep 5, 2013. BTW… air is not "heavy" when it's moist. Water vapor is lighter than dry air. #idwx pic.twitter.com/i2RAAjS9CY
— NWS Boise (@NWSBoise) August 26, 2020
On August 26th, a long-lived supercell thunderstorm tracked across Owyhee County with 2″ diameter hail.
Today's severe thunderstorm ((with 2" diameter hail) in Owyhee County moved due east while all the other cells were moving northeast. A right-moving storm is a classic indicator of a severe thunderstorm. #idwx pic.twitter.com/E4GwMrGKu8
— NWS Boise (@NWSBoise) August 27, 2020
Overnight on the 29th, a dry cold front brought much cooler air from western Canada. Highs were around 15 degrees lower than on the previous day.
Northwest winds at the surface and aloft behind the front temporarily swept away most of the smoke.
— NWS Boise (@NWSBoise) August 30, 2020
On the 31st, a weather system from British Columbia brought clouds, a breezy afternoon, and slightly cooler air.
Here's the August climate stats for a few cities across southwest Idaho and southeast Oregon. Temperatures on average ended up a couple of degrees above normal, with below normal precipitation. For more info: https://t.co/Z7cad5jhox #IDwx #ORwx pic.twitter.com/yeytb9f4oE
— NWS Boise (@NWSBoise) September 3, 2020