229 NOUS45 KTFX 041932 PNSTFX Public Information Statement National Weather Service Great Falls MT 134 PM MDT Tue Sep 4 2018 MTZ008>015-044>055-151450- ...August 2018 and June-August Seasonal Weather Summary for North Central and Southwest Montana... A ridge of high pressure was over the Rocky Mountains during August. This was normal for the month, with a general westerly flow aloft. Temperature departures from normal were very small...up to 1.5 degrees. Precipitation was mostly below normal, with a small strip of above normal from near Big Sky to Martinsdale. Winds averaged below normal. Temperatures started out very warm across the region during August. There was a sharp cool-down on the by the 4th. Isolated thunderstorms caused outflow winds to 58 mph at Vaughn on the 3rd. After a short period with normal and below normal temperatures, they shot up into the 95-105F range from the 9th-11th. Armells Creek (Fergus) reached 108F on the 11th for the area's highest for the month. After continual warmth, temperatures fell to below normal on the 19th. A cold front with thunderstorms brought severe thunderstorms to southwest Montana on the 20th. A small tornado was reported near Wisdom on the 20th. A collapsing thunderstorm caused wind gusts to 73-mph at Little Bullwhacker Creek (Blaine) early in the morning on the 20th. The coolest period of the month was from the 26th-28th. With rain falling across much of central Montana, temperatures stayed cool as well. During the rain, some spots were in the mid-40s during the afternoon of the 27th. Some snow fell at higher elevations in the Rockies and Little Belts. Temperatures pushed back to normal values to end the month. #### Temperature #### Average temperature departures ranged from near normal at most locations to 1.6 degrees below normal at Dillon. Little Bullwhacker (Blaine) had the warmest area average, 71.6F, while the coolest August average was 52.4F at Whiskey Creek (Gallatin). August's temperature extremes were 108F at Armells Creek on the 11th and 20F at Gates Park on the 28th. Great Falls had an absolute temperature range of 66F (Max of 102F and min of 36F. This was their second highest August temperature range. The greatest range of 67 degrees was set in 1992. The area's composite average temperature was 64.1F, 0.7F below normal, and the 56th coolest of record. Dillon and Lewistown had their coolest August since 2010. For the summer season (June-August), temperatures averaged at normal. The warmest summer average temperature was 69.9F at Little Bullwhacker Creek (Blaine), while the coolest was 51.8F at Porphory Peak (Meagher). The highest temperature was 108F at Armells Creek in August. This is the warmest area temperature since 2007, when it was 108F at Big Sandy. The lowest temperature was 20F at Elk Park in June and at Gates Park in August. The water-year-to-date's area average temperature is 39.5F. This is 1.6F below normal and the 26th coolest of record. Helena has had their 27th warmest summer but coolest since 2011. Dillon and Lewistown have had their coolest summer since 2010. #### Precipitation #### For precipitation, August produced below normal rainfall, except for a strip from Big Sky to Martinsdale. Isolated thunderstorms produced the only rain for much of the month. The general rain on the 27th covered a much larger area. The highest monthly rain amounts were in the southwest. Lone Mountain reported 3.00-inches, while Norris Madison reported 2.34-inches. There were 4 days with severe thunderstorms, which is twice normal for August. The area precipitation average was 0.80". This was 0.38" below normal, and the 50th driest of record. For the summer season, this was the 51st driest of record. The mean precipitation was 4.50", or 0.62" below normal. For the area, although below normal, this was the wettest summer since 2014. The highest area summer precipitaiton was 11.10-inches at Shower Falls, while Lewistown 11ESE reported 10.28-inches. Havre had twice their precipitation of last summer (2.43-inches), but this was still their 8th driest of record. #### Wind #### Wind speeds were below average at most locations. Of airport locations, Cut Bank had the strongest monthly average of 10.5 mph, which just above their long-term average. The windiest location was near Browning, with an average of 11.9 mph. Higher elevations (Deep Creek) reported an average speed of 13.2 mph. Thunderstorm gusts were generally in the 60 mph range. The strongest gust was from a collapsing thunderstorm that produced a speed of 78- mph near Wisdom on the 20th. For the summer period, as an areal composite, this was the 9th calmest such period of record. The mean wind speed was 7.9 mph, or 0.2 mph below normal. The highest area gust was 78 mph near Wisdom in August. Smoke from wild fires affected the skies and visibility of central and southwest Montana during August. Ranking givin if within the top or bottom 25...except area average. Average Temperature...Degrees Fahrenheit... Aug Norm Rank Jun-Aug Norm Rank Bozeman......64.7..65.7... 64.0....63.9... Bozeman MSU..65.0..66.5... 63.6....64.6... Cut Bank.....63.6..63.6... 62.4....62.0... Dillon.......62.6..64.2...19th coolest 61.9....62.7...19th coolest Great Falls..66.6..66.3... 65.3....64.5... Havre........67.5..68.0... 67.0....66.5... Helena.......68.1..68.3... 67.0....66.8... Lewistown....64.0..65.1... 62.5....62.9... W Yellowstne 55.4..57.1...24th coolest 55.1....55.8...20th coolest Area.........64.1..64.8...52nd coolest 63.1....63.1...55th coolest Precipitation...Inches... Aug Norm Rank Jun-Aug Norm Rank Bozeman.......0.95..1.07... 5.04....4.68... Bozeman MSU...1.45..1.43... 6.29....6.00... Cut Bank......0.39..1.16...17th driest 3.52....4.99... Dillon........0.78..1.06... 3.83....4.28... Great Falls...0.67..1.57... 4.09....5.60... Havre.........0.62..1.11... 2.43....4.94... 8th driest Helena........0.40..1.20... 3.77....4.45... Lewistown.....1.13..1.73... 7.38... 6.74... W Yellowstne 0.85..1.14... 4.19....5.05... Area..........0.80..1.19...50th driest 4.50....3.05...51th driest Average Wind Speed...MPH... Aug Norm Rank Jun-Aug Norm Rank Bozeman.......5.5....6.3... 7th calmest 5.5.... 6.2... 5th calmest Cut Bank.....10.5...10.4... 11.2....11.1... Dillon........7.7... 7.5...15th calmest 7.6.... 7.9...19th calmest Great Falls.. 9.4... 9.6... 9.6....10.0... Havre........ 8.3....8.2... 9.0.....8.5... Helena....... 6.4....6.6... 7.0.... 7.3...21st calmest Lewistown.... 7.0... 7.9 ..14th calmest 7.4.... 8.1...11th calmest W Yellowstone 4.8 2nd calmest 5.5 Area..........7.4....7.7... 8th calmest 7.9.....8.1... 9th calmest Temperature and precipitation records for Bozeman began in 1935, Cut Bank began in 1903, Dillon began in 1939, Great Falls began in 1891, Havre and Helena began in 1880, and Lewistown began in 1896 and West Yellowstone in 1905. Wind records at Bozeman and Dillon began in 1948, Cut Bank and Lewistown in 1938, Great Falls in 1939, Havre in 1899, Helena in 1880 and West Yellowstone in 2010. Bozeman MSU temperature began in 1892 and precipitation in 1868 (Fort Ellis). The normal period for all elements is 1981 TO 2010. These data are preliminary and have not undergone final QC by NCEI. Therefore these data are subject to revision. Final and certified climate data can be accessed at the National Centers for Environmental Information at www.ncei.noaa.gov $$ && NNNN