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:  August 25, 2020

 

 Upper Missouri Basin


July precipitation across the Upper Missouri Basin was near to below average. Basin precipitation summaries for the Missouri Basin include: Milk St. Mary, 34 percent; Milk Canada, 52 percent; Lower Milk, 111 percent; above Toston, 61 percent; Toston to Ft. Peck, 49 percent. 

Of the four major irrigation reservoirs in Montana; Lima Reservoir had 151 percent average storage, Clark Canyon was holding 106 percent of average water, Gibson Reservoir had 131 percent of average stored water, and Fresno Reservoir had 49 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; 101 and 118 percent of average water, respectively.



Yellowstone Basin 

Precipitation during July was near average. The upper Yellowstone River Basin received 47 percent of average precipitation while the Lower Yellowstone River Basin reported 71 percent of average. The Bighorn Basin received 31 percent of average precipitation while the Wind River Basin received 29 percent of average. The Little Bighorn - Upper Tongue Basin received 48 percent of average and the Powder River had 52 percent of average precipitation.

Monthend storage at Boysen Reservoir was 100 percent of average. Stored water in Buffalo Bill Reservoir was 123 percent of average. Monthend storage was 100 percent of average at Bighorn Reservoir.

 

Platte Basin 

Precipitation during July in the Upper North Platte Basin was 30 percent of average.  In the Lower North Platte Basin, precipitation was 33 percent of average.  The North Platte Plains below Guernsy Reservoir had 53 percent.  The South Platte Mountains had 56 percent whereas the Plains had 77 percent of average July precipitation.

Stored water in the South Platte Basin was 119 percent of average on July 1.

 

PRECIPITATION MAPS
July 2020  WY 2020
July 2020 Precipitation Percent of 1981-2010 Average WY2020 Precipitation as Percent of 1981-2010 Average
July 2020 Basin Mean Precipitation          WY2020 Basin Mean Precipitation
July 2020 MBRFC Basin Mean Precipitation      WY2020 MBRFC Basin Mean Precipitation