May 1, 2018 Spring and Summer Streamflow Forecasts
Missouri River Basin Mountain Snowpack as of May 1, 2018
Upper Missouri Basin
The high elevation snow pack in the Upper Missouri Basin as of May 1
was above average. The snow pack above Fort Peck, Montana was
172 percent. The snow pack in the St. Mary Basin was 153 percent, and the
Milk River Basin was 152 percent.
April precipitation across the Upper Missouri Basin was near to above average.
Basin precipitation summaries for the Missouri Basin include: Milk St. Mary,
97 percent; Milk Canada, 91 percent; Lower Milk, 83 percent; above Toston,
141 percent; Toston to Ft. Peck, 124 percent.
April 2018 Upper Missouri Mean Precip Oct-Apr WY2018 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 165 percent of average
for the Missouri Basin above Fort Peck, Montana.
Upper Missouri May 1, 2018 Spring and Summer Streamflow Forecasts
Of the four major irrigation reservoirs in Montana; Lima
Reservoir had 133 percent average storage, Clark Canyon was
holding 124 percent of average water, Gibson Reservoir had 64
percent of average stored water, and Fresno Reservoir had
111 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; 90 and 124 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 171 percent of average. The snow packs in the Wind, Bighorn, and Shoshone Basins were 117, 144, and 149 percent of average, respectively. The snow packs in the Tongue and Powder basins were 117 and 125 percent of average, respectively. Precipitation during April was near to above average. The upper Yellowstone River Basin received 146 percent of average precipitation while the Lower Yellowstone River Basin reported 163 percent of average. The Bighorn Basin received 115 percent of average precipitation while the Wind River Basin received 73 percent of average. The Little Bighorn - Upper Tongue Basin received 109 percent of average and the Powder River had 86 percent of average precipitation.
April 2018 Yellowstone Mean Precip Oct-Apr WY2018 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
in the 160-180 percent of average range. Flow in the Tongue Basin is
expected to be about 110 percent of average. Flows in the Powder River
are expected to be about 90 percent of average.
Monthend storage at Boysen Reservoir was 88 percent of average.
Stored water in Buffalo Bill Reservoir was 104 percent of average.
Monthend storage was 92 percent of average at Bighorn Reservoir.
Yellowstone May 1, 2018 Spring and Summer Streamflow Forecasts
Platte Basin
The high elevation snow pack in the Upper North Platte Basin was
82 percent of average on May 1. The snow pack in the North Platte
Basin below Seminoe Reservoir was 40 percent of average. The snow
pack in the South Platte Basin was 81 percent of average.
Precipitation during April in the Upper North Platte Basin was 67
percent of average. In the Lower North Platte Basin, precipitation
was 50 percent of average. The North Platte Plains below Guernsy
Reservoir had 61 percent. The South Platte Mountains had 60
percent whereas the Plains had 67 percent of average April precipitation.
April 2018 Platte Mean Precip Oct-Apr WY2018 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 110 percent of average. Streams in the South Platte
Basin above South Platte, Colorado can expect 50 percent
of average flow. For the remainder of the South Platte
basin, flows are expected near 65 percent.
Stored water in the South Platte Basin was 119 percent of average
on May 1.
North Platte Streamflow Fcst South Platte Streamflow Fcst
000 FGUS63 KKRF 011607 ESPKRF WATER SUPPLY FORECAST NWS MISSOURI BASIN RIVER FORECAST CENTER PLEASANT HILL MISSOURI 1100 CDT TUESDAY MAY 01 2018 DATA CURRENT AS OF MAY 01 2018 MISSOURI/YELLOWSTONE/PLATTE RIVER BASIN FORECASTS 50% % 10% 90% AVG FORECAST POINT PERIOD (KAF) AVG (KAF) (KAF) (KAF) --------------------------------------------------------------------- BOYSEN RESERVOIR INFLOW MAY-SEP 1360 135% 1733 1160 1009 SBDW4N BIGHORN R AT KANE MAY-SEP 1987 121% 2521 1715 1644 LVEW4N GREYBULL R NR MEETEETSE MAY-SEP 230 89% 340 186 259 MEEW4N BUFFALO BILL RESERVOIR INFLOW MAY-SEP 1023 159% 1103 905 645 CDYW4N ST MARY R NR BABB MAY-SEP 491 125% 564 425 392 SMYM8N ST MARY R AT INT BOUNDARY MAY-SEP 579 129% 682 495 447 SMBM8N MILK R NR CUTBANK MAY-SEP 29 108% 97 20 27 PDBM8N MILK R AT EASTERN CROSSING MAY-SEP 94 205% 234 67 46 ERNM8N NORTH PLATTE R NR NORTHGATE MAY-SEP 227 120% 309 165 189 NGTC2 ENCAMPMENT R NR ENCAMPMENT MAY-SEP 128 83% 160 112 154 ERCW4 ENCAMPMENT R NR ENCAMPMENT MAY-SEP 137 84% 168 120 162 ECRW4N ROCK CK NR ARLINGTON MAY-SEP 55 126% 64 49 44 KCRW4 ROCK CK NR ARLINGTON MAY-SEP 55 126% 64 49 44 KCRW4N SEMINOE RESERVOIR INFLOW WY MAY-SEP 691 106% 894 543 649 SETW4 SEMINOE RESERVOIR INFLOW WY MAY-SEP 834 104% 1041 695 800 SETW4N LARAMIE R NR WOODS MAY-SEP 60 112% 99 45 54 WODW4 LARAMIE R NR WOODS MAY-SEP 94 107% 133 77 88 WODW4N LITTLE LARAMIE R NR FILMORE MAY-SEP 55 113% 68 46 48 SMTW4 LITTLE LARAMIE R NR FILMORE MAY-SEP 57 113% 70 48 50 SMTW4N ANTERO RESERVOIR INFLOW MAY-SEP 5 33% 8 3 15 ANRC2N SPINNEY MOUNTAIN RES INFLOW MAY-SEP 24 45% 44 19 53 SPYC2N ELEVENMILE CANYON RES INFLOW MAY-SEP 25 43% 47 19 58 EVNC2N CHEESMAN LAKE INFLOW MAY-SEP 48 45% 92 37 106 CHEC2N SOUTH PLATTE R AT SOUTH PLATTE MAY-SEP 95 50% 163 74 190 SPTC2N BEAR CK AT MORRISON MAY-SEP 8 49% 16 5 17 MRRC2N CLEAR CK AT GOLDEN MAY-SEP 75 71% 116 61 106 GLDC2N ST VRAIN CK AT LYONS MAY-SEP 54 58% 85 42 92 LNSC2N BOULDER CK NR ORODELL MAY-SEP 32 64% 63 26 50 OROC2N S BOULDER CK NR ELDORADO SPR MAY-SEP 20 58% 39 15 35 BELC2N CACHE LA POUDRE AT CANYON MOUTH MAY-SEP 184 94% 264 158 195 FTDC2N LIMA RESERVOIR INFLOW MAY-SEP 42 80% 63 27 53 LRRM8N CLARK CANYON RESERVOIR INFLOW MAY-SEP 107 75% 177 71 142 CLKM8N BEAVERHEAD R AT BARRETTS MAY-SEP 144 83% 222 102 173 BARM8N RUBY R RESERVOIR INFLOW MAY-SEP 83 105% 108 69 80 ALRM8N BIG HOLE R NR MELROSE MAY-SEP 1040 228% 1308 901 456 MLRM8 BIG HOLE R NR MELROSE MAY-SEP 1099 216% 1365 958 509 MLRM8N HEBGEN RESERVOIR INFLOW MAY-SEP 589 162% 648 524 363 HBDM8N ENNIS RESERVOIR INFLOW MAY-SEP 964 148% 1075 840 652 ELMM8N GALLATIN R NR GATEWAY MAY-SEP 545 122% 675 454 445 GLGM8 GALLATIN R NR GATEWAY MAY-SEP 545 128% 675 454 425 GLGM8N GALLATIN R AT LOGAN MAY-SEP 628 164% 817 494 382 LOGM8 GALLATIN R AT LOGAN MAY-SEP 763 148% 931 650 514 LOGM8N MISSOURI R AT TOSTON MAY-SEP 3821 174% 4546 3251 2194 TOSM8N MISSOURI R AT FORT BENTON MAY-SEP 5424 159% 6795 4721 3420 FBNM8N MISSOURI R NR VIRGELLE MAY-SEP 6078 159% 7778 5312 3832 VRGM8N MISSOURI R NR LANDUSKY MAY-SEP 6328 159% 8127 5558 3978 LDKM8N MISSOURI R BLW FT PECK DAM MAY-SEP 6778 162% 8601 5900 4177 FPKM8N GIBSON RESERVOIR INFLOW MAY-SEP 863 264% 1030 807 327 AGSM8N MARIAS R NR SHELBY MAY-SEP 414 194% 598 327 213 SHLM8N MUSSELSHELL R AT HARLOWTON MAY-SEP 119 190% 196 83 62 HLWM8N YELLOWSTONE R AT YELLOWSTONE LK MAY-SEP 1189 180% 1287 1106 660 YLOW4APR YELLOWSTONE R AT YELLOWSTONE LK MAY-SEP 1389 171% 1480 1267 812 YLOW4N YELLOWSTONE R AT CORWIN SPRINGS MAY-SEP 2831 183% 3047 2648 1549 CORM8 YELLOWSTONE R AT CORWIN SPRINGS MAY-SEP 3115 171% 3349 2928 1823 CORM8N YELLOWSTONE R AT LIVINGSTON MAY-SEP 3167 173% 3445 2970 1834 LIVM8 YELLOWSTONE R AT LIVINGSTON MAY-SEP 3537 163% 3804 3319 2175 LIVM8N YELLOWSTONE R AT BILLINGS MAY-SEP 5773 183% 6476 5318 3149 BILM8 YELLOWSTONE R AT BILLINGS MAY-SEP 6897 166% 7602 6435 4163 BILM8N YELLOWSTONE R AT MILES CITY MAY-SEP 10598 150% 11914 9769 7084 MILM8N YELLOWSTONE R AT SIDNEY MAY-SEP 10946 148% 12396 10028 7400 SIDM8N BOULDER R AT BIG TIMBER MAY-SEP 351 156% 404 322 225 BTMM8 BOULDER R AT BIG TIMBER MAY-SEP 460 142% 509 426 325 BTMM8N STILLWATER R NR ABSAROKEE MAY-SEP 749 152% 851 691 493 SRAM8 STILLWATER R NR ABSAROKEE MAY-SEP 809 147% 910 752 551 SRAM8N CLARKS FK YELWSTONE R NR BELFRY MAY-SEP 1025 206% 1121 962 497 BFYM4 CLARKS FK YELWSTONE R NR BELFRY MAY-SEP 1090 192% 1192 1032 568 BFYM4N BIGHORN R NR ST XAVIER MAY-SEP 3178 134% 3827 2818 2371 STXM8N LITTLE BIGHORN R NR HARDIN MAY-SEP 85 95% 116 70 90 HRDM8N TONGUE R NR DAYTON MAY-SEP 100 116% 131 80 86 DAYW4N TONGUE R NR DECKER MAY-SEP 213 103% 313 173 207 DSLM8N TONGUE R RESERVOIR INFLOW MAY-SEP 213 103% 315 173 207 DKRM8N POWDER R NR LOCATE MAY-SEP 216 90% 323 170 239 MHDM8 POWDER R NR LOCATE MAY-SEP 243 91% 362 185 267 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 1981-2010 THE 50%, 10% AND 90% COLUMNS INDICATE THE PROBABILITY THAT THE ACTUAL VOLUME WILL EXCEED THE FORECAST FOR THE VALID TIME PERIOD FOR MORE INFORMATION PLEASE VISIT: WWW.WEATHER.GOV/MBRFC/WATER
