National Weather Service Raw Text Product

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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 

$$
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