May 1, 2017 Spring and Summer Streamflow Forecasts
Missouri River Basin Mountain Snowpack as of May 1, 2017
Upper Missouri Basin
The high elevation snow pack in the Upper Missouri Basin as of May 1
was near to above average. The snow pack above Fort Peck, Montana was
100 percent. The snow pack in the St. Mary Basin was 125 percent, and the
Milk River Basin was 124 percent.
April precipitation across the Upper Missouri Basin was near to above average.
Basin precipitation summaries for the Missouri Basin include: Milk St. Mary,
134 percent; Milk Canada, 147 percent; Lower Milk, 88 percent; above Toston,
132 percent; Toston to Ft. Peck, 133 percent.
April 2017 Upper Missouri Mean Precip Oct-Apr WY2017 Upper Missouri Mean Precip
Stream flow in the Upper Missouri Basin is forecast to be
above average during the upcoming Spring and Summer.
Runoff is expected to range around 125 percent of average
for the Missouri Basin above Fort Peck, Montana.
Upper Missouri May 1, 2017 Spring and Summer Streamflow Forecasts
Of the four major irrigation reservoirs in Montana; Lima
Reservoir had 138 percent average storage, Clark Canyon was
holding 97 percent of average water, Gibson Reservoir had 74
percent of average stored water, and Fresno Reservoir had
117 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; 106 and 119 percent of average water, respectively.
Yellowstone Basin
The high elevation snow pack in the Yellowstone Basin was above average on May 1. The snow pack in the Upper Yellowstone Basin was 156 percent of average. The snow packs in the Wind, Bighorn, and Shoshone Basins were 236, 149, and 147 percent of average, respectively. The snow packs in the Tongue and Powder basins were 138 and 157 percent of average, respectively. Precipitation during April was above average. The upper Yellowstone River Basin received 157 percent of average precipitation while the Lower Yellowstone River Basin reported 130 percent of average. The Bighorn Basin received 253 percent of average precipitation while the Wind River Basin received 215 percent of average. The Little Bighorn - Upper Tongue Basin received 248 percent of average and the Powder River had 220 percent of average precipitation.
April 2017 Yellowstone Mean Precip Oct-Apr WY2017 Yellowstone Mean Precip
Forecast stream flow in the Yellowstone Basin are above average
for the upcoming Spring and Summer. Stream flow for the
Yellowstone River above Sidney, Montana is forecast to be
about 160 percent of average. Flow in the Tongue Basin is expected
to be 130 percent of average. Flows in the Powder River are expected
to be about 137 percent of average.
Monthend storage at Boysen Reservoir was 89 percent of average.
Stored water in Buffalo Bill Reservoir was 106 percent of average.
Monthend storage was 94 percent of average at Bighorn Reservoir.
Yellowstone May 1, 2017 Spring and Summer Streamflow Forecasts
Platte Basin
The high elevation snow pack in the Upper North Platte Basin was
92 percent of average on May 1. The snow pack in the North Platte
Basin below Seminoe Reservoir was 101 percent of average. The snow
pack in the South Platte Basin was 95 percent of average.
Precipitation during April in the Upper North Platte Basin was 112
percent of average. In the Lower North Platte Basin, precipitation
was 136 percent of average. The North Platte Plains below Guernsy
Reservoir had 138 percent. The South Platte Mountains had 105
percent whereas the Plains had 139 percent of average April precipitation.
April 2017 Platte Mean Precip Oct-Apr WY2017 Platte Mean Precip
Stream flow in the Platte Basin is forecast to be near
average during the upcoming Spring and Summer. Runoff
for streams above Seminoe Reservoir are expected to be
about 130 percent of average. Streams in the South Platte
Basin above South Platte, Colorado can expect 63 percent
of average flow. For the remainder of the South Platte
basin, flows are expected near 72 percent.
Stored water in the South Platte Basin was 106 percent of average
on May 1.
North Platte Streamflow Fcst South Platte Streamflow Fcst
Water Supply Forecast NWS Missouri Basin River Forecast Center Pleasant Hill, Missouri 1200 CST Thursday May 4 2017 Data current as of: May 2 2017 Missouri/Yellowstone/Platte River Basin Forecasts 50% % 10% 90% AVG Forecast Point Period (KAF) AVG (KAF)(KAF)(KAF) ----------------------------------------------------------------- Boysen Reservoir Inflow Apr-Sep 1659 225% 1979 1486 736 SBDW4N Bighorn R at Kane Apr-Sep 2961 201% 3486 2604 1472 LVEW4N Greybull R nr Meeteetse Apr-Sep 301 131% 371 258 231 MEEW4N Buffalo Bill Reservoir Inflow Apr-Sep 1060 137% 1218 968 774 CDYW4N St Mary R nr Babb Apr-Sep 473 122% 541 399 388 SMYM8N St Mary R at Int Boundary Apr-Sep 545 123% 645 455 443 SMBM8N Milk R nr Cutbank Apr-Sep 22 81% 74 14 27 PDBM8N Milk R at Eastern Crossing Apr-Sep 37 83% 124 21 45 ERNM8N North Platte R nr Northgate Apr-Sep 334 178% 410 278 188 NGTC2 Encampment R nr Encampment Apr-Sep 194 126% 227 175 154 ERCW4 Encampment R nr Encampment Apr-Sep 202 125% 235 183 161 ECRW4N Rock Ck nr Arlington Apr-Sep 61 140% 70 54 44 KCRW4 Rock Ck nr Arlington Apr-Sep 62 141% 71 55 44 KCRW4N Seminoe Reservoir Inflow WY Apr-Sep 881 137% 1072 732 645 SETW4 Seminoe Reservoir Inflow WY Apr-Sep 1027 129% 1217 887 794 SETW4N Laramie R nr Woods Apr-Sep 73 136% 112 54 54 WODW4 Laramie R nr Woods Apr-Sep 106 122% 146 88 87 WODW4N Little Laramie R nr Filmore Apr-Sep 47 97% 60 39 48 SMTW4 Little Laramie R nr Filmore Apr-Sep 49 97% 62 41 50 SMTW4N Antero Reservoir Inflow Apr-Sep 11 74% 14 9 15 ANRC2N Spinney Mountain Res Inflow Apr-Sep 36 68% 58 25 53 SPYC2N Elevenmile Canyon Res Inflow Apr-Sep 37 64% 62 26 57 EVNC2N Cheesman Lake Inflow Apr-Sep 54 51% 99 39 106 CHEC2N South Platte R at South Platte Apr-Sep 100 53% 173 74 188 SPTC2N Bear Ck at Morrison Apr-Sep 10 61% 19 7 16 MRRC2N Clear Ck at Golden Apr-Sep 66 62% 116 52 106 GLDC2N St Vrain Ck at Lyons Apr-Sep 77 84% 114 64 92 LNSC2N Boulder Ck nr Orodell Apr-Sep 36 71% 64 29 50 OROC2N S Boulder Ck nr Eldorado Spr Apr-Sep 17 48% 42 11 35 BELC2N Cache La Poudre at Canyon Mouth Apr-Sep 184 95% 250 159 195 FTDC2N Lima Reservoir Inflow Apr-Sep 45 86% 66 30 52 LRRM8N Clark Canyon Reservoir Inflow Apr-Sep 138 99% 210 95 140 CLKM8N Beaverhead R at Barretts Apr-Sep 172 100% 251 124 172 BARM8N Ruby R Reservoir Inflow Apr-Sep 76 96% 96 64 79 ALRM8N Big Hole R nr Melrose Apr-Sep 865 190% 1100 721 455 MLRM8 Big Hole R nr Melrose Apr-Sep 926 182% 1158 780 507 MLRM8N Hebgen Reservoir Inflow Apr-Sep 563 156% 619 498 360 HBDM8N Ennis Reservoir Inflow Apr-Sep 878 136% 974 759 646 ELMM8N Gallatin R nr Gateway Apr-Sep 482 109% 598 392 443 GLGM8 Gallatin R nr Gateway Apr-Sep 482 114% 598 392 424 GLGM8N Gallatin R at Logan Apr-Sep 497 131% 684 382 380 LOGM8 Gallatin R at Logan Apr-Sep 632 124% 794 532 511 LOGM8N Missouri R at Toston Apr-Sep 3012 138% 3657 2524 2187 TOSM8N Missouri R at Fort Benton Apr-Sep 4144 122% 5172 3525 3396 FBNM8N Missouri R nr Virgelle Apr-Sep 4628 121% 5929 3995 3810 VRGM8N Missouri R nr Landusky Apr-Sep 4843 122% 6289 4202 3956 LDKM8N Missouri R blw Ft Peck Dam Apr-Sep 5019 121% 6474 4349 4153 FPKM8N Gibson Reservoir Inflow Apr-Sep 670 206% 815 615 326 AGSM8N Marias R nr Shelby Apr-Sep 399 190% 549 326 210 SHLM8N Musselshell R at Harlowton Apr-Sep 35 57% 60 18 62 HLWM8N Yellowstone R at Yellowstone Lk Apr-Sep 1402 210% 1489 1291 666 YLOW4APR Yellowstone R at Yellowstone Lk Apr-Sep 1596 199% 1679 1450 803 YLOW4N Yellowstone R at Corwin Springs Apr-Sep 2687 173% 2916 2492 1555 CORM8 Yellowstone R at Corwin Springs Apr-Sep 2988 166% 3213 2758 1802 CORM8N Yellowstone R at Livingston Apr-Sep 2945 160% 3212 2742 1845 LIVM8 Yellowstone R at Livingston Apr-Sep 3310 154% 3580 3069 2152 LIVM8N Yellowstone R at Billings Apr-Sep 4766 150% 5416 4364 3183 BILM8 Yellowstone R at Billings Apr-Sep 5737 138% 6373 5308 4156 BILM8N Yellowstone R at Miles City Apr-Sep 10454 146% 1169596587160 MILM8N Yellowstone R at Sidney Apr-Sep 10926 146% 12372100657478 SIDM8N Boulder R at Big Timber Apr-Sep 227 98% 263 202 231 BTMM8 Boulder R at Big Timber Apr-Sep 331 102% 364 300 324 BTMM8N Stillwater R nr Absarokee Apr-Sep 631 126% 715 576 500 SRAM8 Stillwater R nr Absarokee Apr-Sep 690 125% 773 638 550 SRAM8N Clarks Fk Yelwstone R nr Belfry Apr-Sep 913 183% 1013 849 498 BFYM4 Clarks Fk Yelwstone R nr Belfry Apr-Sep 869 153% 967 803 566 BFYM4N Bighorn R nr St Xavier Apr-Sep 4149 178% 4890 3721 2332 STXM8N Little Bighorn R nr Hardin Apr-Sep 97 109% 133 82 89 HRDM8N Tongue R nr Dayton Apr-Sep 121 140% 153 96 86 DAYW4N Tongue R nr Decker Apr-Sep 270 124% 374 216 218 DSLM8N Tongue R Reservoir Inflow Apr-Sep 271 124% 378 217 218 DKRM8N Powder R nr Locate Apr-Sep 353 143% 470 292 247 MHDM8 Powder R nr Locate Apr-Sep 383 137% 509 316 279 LOCM8N Locations with an "N" suffix indicate natural flows excluding stream augmentations KAF: Thousands of acre-feet %AVG: Current 50%/avg AVG: Average (50%) seasonal runoff volume as simulated by the river forecast model considering a continuous simulation of the basin response to historic climate data (observed precipitation and temperatures) over the period of 1979-2001 The 50%, 10%, and 90% columns indicate the probablility that the actual volume will exceed the forecast for the valid time period
