National Weather Service United States Department of Commerce

Missouri Basin River Forecast Center
Water Supply Statement
Issued in cooperation with the Natural
Resources Conservation Service
Issued:  September 23, 2018

 

UPPER MISSOURI BASIN

 

August precipitation across the Upper Missouri Basin was below average.
Basin precipitation summaries for the Missouri Basin include: Milk St. Mary,
64 percent; Milk Canada, 73 percent; Lower Milk, 60 percent; above Toston,
78 percent; Toston to Ft. Peck, 77 percent.

Of the four major irrigation reservoirs in Montana; Lima
Reservoir had 173 percent average storage, Clark Canyon was
holding 159 percent of average water, Gibson Reservoir had 99
percent of average stored water, and Fresno Reservoir had
84 percent of average stored water.

The major hydroelectric reservoirs in Montana (Canyon Ferry and
Fort Peck), had monthend storage in the average to above
average range; 103 and 125 percent of average water, respectively.

 

 

YELLOWSTONE BASIN

Precipitation during August was above average. The upper Yellowstone River Basin received 135 percent of average precipitation while the Lower Yellowstone River Basin reported 149 percent of average. The Bighorn Basin received 128 percent of average precipitation while the Wind River Basin received 61 percent of average. The Little Bighorn - Upper Tongue Basin received 171 percent of average and the Powder River had 117 percent of average precipitation.


Monthend storage at Boysen Reservoir was 113 percent of average. Stored water in Buffalo Bill Reservoir was 132 percent of average. Monthend storage was 104 percent of average at Bighorn Reservoir.

 

PLATTE BASIN

 

Precipitation during August in the Upper North Platte Basin was 97 percent of average. In the Lower North Platte Basin, precipitation was 80 percent of average. The North Platte Plains below Guernsey Reservoir had 58 percent. The South Platte Mountains had 46 percent whereas the Plains had 74 percent of average August precipitation.

Stored water in the South Platte Basin was 105 percent of average on September 1.
 

 

PRECIPITATION MAPS
August 2018  WY 2018
August 2018 Precipitation Percent of 1981-2010 Average WY2018 Precipitation as Percent of 1981-2010 Average
August 2018 Basin Mean Precipitation          WY2018 Basin Mean Precipitation
August 2018 MBRFC Basin Mean Precipitation      WY2018 MBRFC Basin Mean Precipitation