A ridge of high pressure brought a record breaking heat wave across lower elevations in northwest Montana August 9th and 10th.

Excessive Heat in LOWER CLARK FORK REGION, MONTANA
From 09-AUG-18 12:00:00 to 10-AUG-18 20:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Thompson Falls tied an all-time record high of 107 on the 10th and reached 106 on the 9th. The highest two day mean high temperature ever for Thompson Falls occurred on the 9th and the 10th with observations going back to 1956. Superior reached a record high of 105 on the 9th and 107 on the 10th, ranking as the third hottest two day maximum mean temperature stretch with observations going back to 1914.  Heron also set a record high of 102 on the 10th. Even though near-record to record high temperatures were observed on the 9th and 10th, overnight temperatures dropped in the mid to upper 50s at night.

Excessive Heat in MISSOULA / BITTERROOT VALLEYS, MONTANA
From 09-AUG-18 12:00:00 to 10-AUG-18 20:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Missoula reached a record high of 104 on the 10th. Hamilton and Stevensville recorded near record highs of 97 on the 10th. Even with record to near record highs on the 10th, overnight lows on the 9th and 10th dropped in the low to mid 50s.

Excessive Heat in POTOMAC / SEELEY LAKE REGION, MONTANA
From 09-AUG-18 12:00:00 to 10-AUG-18 20:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Seeley Lake reached a record high of 98 on the 10th and tied a record high of 95 on the 9th. Potomac also set a record high of 100 on the 10th. Low temperatures on the 10th dropped into the low to mid 40s.

Excessive Heat in KOOTENAI/CABINET REGION, MONTANA
From 09-AUG-18 12:00:00 to 10-AUG-18 20:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

The Libby Dam recorded an all-time high temperature of 108 on the 10th with observations going back to 1986. In addition, a mean two day maximum temperature of 104.5 on the 9th and 10th was the hottest on record. Eureka set all-time record highs of 106 on the 9th and 10th.  The maximum two day mean of 106 is 1.5 degrees warmer than the next hottest two day stretch with observations going back to 1960. Troy also set a record high of 106 on the 10th. Even though record or near record highs were observed on the 9th and 10th, overnight lows still dropped into the mid 50s to low 60s.

Excessive Heat in WEST GLACIER REGION, MONTANA
From 09-AUG-18 12:00:00 to 10-AUG-18 20:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

West Glacier set an all-time record high of 100 on the August 10th. The two day mean high of 99.5 on the 9th and 10th was the hottest on record going back to 1948. Hungry Horse Dam also set a record high on the 10th of 102. Swan Lake reached 99 on the 9th and set an all-time record high of 106 on the 10th. This two day stretch tied the all-time hottest two day mean maximum temperature stretch with observations going back to 1963. Even with near record to record high temperatures lows were able to drop into the low 50s to upper 50s.

Excessive Heat in FLATHEAD/MISSION VALLEYS, MONTANA
From 09-AUG-18 12:00:00 to 10-AUG-18 20:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Kalispell reached a record high of 100 on August 10th. Creston also record a record high of 98 on August 10th. The Hot Springs RAWS reached 107 and the Jette RAWS reached 103 on the 10th; however, RAWS sites tend to display a warm bias.  Low temperatures dropped into the low to mid 50s on the morning of the 10th.