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 14, 2018

 

UPPER MISSOURI BASIN

 

July precipitation across the Upper Missouri Basin was below average.
Basin precipitation summaries for the Missouri Basin include: Milk St. Mary,
54 percent; Milk Canada, 72 percent; Lower Milk, 68 percent; above Toston,
25 percent; Toston to Ft. Peck, 36 percent.

Of the four major irrigation reservoirs in Montana; Lima
Reservoir had 172 percent average storage, Clark Canyon was
holding 155 percent of average water, Gibson Reservoir had 131
percent of average stored water, and Fresno Reservoir had
100 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 126 percent of average water, respectively.

 

 

YELLOWSTONE BASIN

Precipitation during July was below average. The upper Yellowstone River Basin received 47 percent of average precipitation while the Lower Yellowstone River Basin reported 66 percent of average. The Bighorn Basin received 50 percent of average precipitation while the Wind River Basin received 66 percent of average. The Little Bighorn - Upper Tongue Basin received 84 percent of average and the Powder River had 91 percent of average precipitation.


Monthend storage at Boysen Reservoir was 113 percent of average. Stored water in Buffalo Bill Reservoir was 127 percent of average. Monthend storage was 105 percent of average at Bighorn Reservoir.

 

PLATTE BASIN

 

Precipitation during July in the Upper North Platte Basin was 73 percent of average. In the Lower North Platte Basin, precipitation was 131 percent of average. The North Platte Plains below Guernsey Reservoir had 119 percent. The South Platte Mountains had 112 percent whereas the Plains had 105 percent of average July precipitation.

Stored water in the South Platte Basin was 106 percent of average on August 1.
 

 

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