May 1, 2020 Spring and Summer Streamflow Forecasts
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 118 percent. The snow pack in the St. Mary Basin was 143 percent, and the Milk River Basin was 137 percent.
April precipitation across the Upper Missouri Basin was below average. Basin precipitation summaries for the Missouri Basin include: Milk St. Mary, 67 percent; Milk Canada, 54 percent; Lower Milk, 34 percent; above Toston, 59 percent; Toston to Ft. Peck, 74 percent.
April 2020 Upper Missouri Mean Precip Oct-Apr WY2020 Upper Missouri Mean Precip
Stream flow in the Upper Missouri Basin is forecast to be above average during the upcoming Spring and Summer. The St. Mary River is forecast to have 115 percent of average May-September flows. Runoff is expected to range around 125 percent of average for the Missouri Basin above Fort Peck, Montana.
Upper Missouri May 1, 2020 Spring and Summer Streamflow Forecasts
Of the four major irrigation reservoirs in Montana; Lima Reservoir had 132 percent average storage, Clark Canyon was holding 117 percent of average water, Gibson Reservoir had 79 percent of average stored water, and Fresno Reservoir had 118 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; 94 and 118 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 113 percent of average. The snow packs in the Wind, Bighorn, and Shoshone Basins were 110, 105, and 98 percent of average, respectively. The snow packs in the Tongue
and Powder basins were 104 and 103 percent of average, respectively.
Precipitation during April was below average. The upper Yellowstone River Basin received 57 percent of average precipitation while the Lower Yellowstone River Basin reported 60 percent of average. The Bighorn Basin received 74 percent of average precipitation while the Wind River Basin received 96 percent of average. The Little Bighorn - Upper Tongue Basin received 76 percent of average and the Powder River had 54 percent of average precipitation.
April 2020 Yellowstone Mean Precip Oct-Apr WY2020 Yellowstone Mean Precip
Forecast stream flow in the Yellowstone Basin is near average for the upcoming Spring and Summer. Stream flow for the Yellowstone River above Sidney, Montana is forecast to be about 108 percent of average. Flow in the Tongue Basin is expected to be 85 percent of average. Flows in the Powder River are expected to be about 91 percent of average.
Monthend storage at Boysen Reservoir was 100 percent of average. Stored water in Buffalo Bill Reservoir was 117 percent of average. Monthend storage was 97 percent of average at Bighorn Reservoir.
Yellowstone May 1, 2020 Spring and Summer Streamflow Forecasts
Platte Basin
The high elevation snow pack in the Upper North Platte Basin was 106 percent of average on May 1. The snow pack in the North Platte Basin below Seminoe Reservoir was 110 percent of average. The snow pack in the South Platte Basin was 118 percent of average.
Precipitation during April in the Upper North Platte Basin was 78 percent of average. In the Lower North Platte Basin, precipitation was 72 percent of average. The North Platte Plains below Guernsy Reservoir had 51 percent. The South Platte Mountains had 64 percent whereas the Plains had 55 percent of average April precipitation.
April 2020 Platte Mean Precip Oct-Apr WY2020 Platte Mean Precip
Stream flow in the Platte Basin is forecast to be near to below average during the upcoming Spring and Summer. Runoff for streams above Seminoe Reservoir are expected to be about 118 percent of average. Streams in the South Platte Basin above South Platte, Colorado can expect 70 percent of average flow. For the remainder of the South Platte basin, flows are expected near 69 percent.
Stored water in the South Platte Basin was 108 percent of average on May 1.
North Platte Streamflow Fcst South Platte Streamflow Fcst
000
FGUS63 KKRF 081509
ESPKRF
WATER SUPPLY FORECAST
NWS MISSOURI BASIN RIVER FORECAST CENTER
PLEASANT HILL MISSOURI
1509 CDT FRIDAY MAY 08, 2020
DATA CURRENT AS OF: MAY 06, 2020
MISSOURI/YELLOWSTONE/PLATTE RIVER BASIN FORECASTS
50% % 10% 90% AVG
FORECAST POINT PERIOD (KAF) AVG (KAF) (KAF) (KAF)
---------------------------------------------------------------------
SBDW4N MAY-SEP 882 90 1226 667 981
BOYSEN RESERVOIR INFLOW
LVEW4N MAY-SEP 1331 86 1763 1039 1552
BIGHORN R AT KANE
MEEW4N MAY-SEP 170 75 235 124 226
GREYBULL R NR MEETEETSE
CDYW4N MAY-SEP 649 99 793 518 655
BUFFALO BILL RESERVOIR INFLOW
SMYM8N MAY-SEP 443 115 497 369 385
ST MARY R NR BABB
SMBM8N MAY-SEP 521 116 603 427 450
ST MARY R NR INT BOUNDARY
PDBM8N MAY-SEP 27 104 77 15 26
MILK R NR WESTERN CROSSING
ERNM8N MAY-SEP 47 100 133 25 47
MILK R AT EASTERN CROSSING
NGTC2 MAY-SEP 337 121 433 283 278
NORTH PLATTE R NR NORTHGATE
ECRW4 MAY-SEP 157 116 181 136 135
ENCAMPMENT R NR ENCAMPMENT
ECRW4N MAY-SEP 165 116 189 145 142
ENCAMPMENT R NR ENCAMPMENT
KCRW4 MAY-SEP 66 137 74 60 49
ROCK CR NR ARLINGTON
KCRW4N MAY-SEP 67 137 74 60 49
ROCK CR NR ARLINGTON
SETW4 MAY-SEP 940 125 1131 789 751
SEMINOE RESERVOIR INFLOW WY
SETW4N MAY-SEP 1083 120 1272 939 901
SEMINOE RESERVOIR INFLOW WY
WODW4 MAY-SEP 80 135 127 65 59
LARAMIE R NR WOODS
WODW4N MAY-SEP 114 124 161 99 92
LARAMIE R NR WOODS
SMTW4 MAY-SEP 71 145 85 61 49
LITTLE LARAMIE R NR FILMORE
SMTW4N MAY-SEP 73 143 87 63 51
LITTLE LARAMIE R NR FILMORE
ANRC2N MAY-SEP 10 68 13 8 14
ANTERO RESERVOIR INFLOW
SPYC2N MAY-SEP 27 60 41 21 46
SPINNEY MOUNTAIN RES INFLOW
EVNC2N MAY-SEP 31 62 46 23 50
ELEVENMILE CANYON RES INFLOW
CHEC2N MAY-SEP 54 58 79 42 94
CHEESMAN LAKE INFLOW
SPTC2N MAY-SEP 105 63 150 84 166
SOUTH PLATTE R AT SOUTH PLATTE
MRRC2N MAY-SEP 7 44 12 4 16
BEAR CK AT MORRISON
GLDC2N MAY-SEP 67 59 88 57 114
CLEAR CK AT GOLDEN
LNSC2N MAY-SEP 67 78 93 57 86
ST VRAIN CK AT LYONS
OROC2N MAY-SEP 37 80 51 33 45
BOULDER CK NR ORODELL
BELC2N MAY-SEP 25 73 40 21 35
S BOULDER CK NR ELDORADO SPR
FTDC2N MAY-SEP 204 110 278 171 186
CACHE LA POUDRE AT CANYON MOUTH
LRRM8N MAY-SEP 61 128 84 43 47
LIMA RESERVOIR INFO
CLKM8N MAY-SEP 112 101 175 82 111
CLARK CANYON RESERVOIR INFLOW
BARM8N MAY-SEP 138 101 206 107 137
BEAVERHEAD R AT BARRETTS
ALRM8N MAY-SEP 71 93 90 59 76
RUBY R RESERVOIR INFLOW
MLRM8 MAY-SEP 475 119 658 396 399
BIG HOLE R NR MELROSE
MLRM8N MAY-SEP 532 118 714 453 451
BIG HOLE R NR MELROSE
HBDM8N MAY-SEP 469 145 540 405 323
HEBGEN RESERVOIR INFFLOW
ELMM8N MAY-SEP 778 137 906 671 568
ENNIS RESERVOIR INFLOW
GLGM8 MAY-SEP 355 87 466 300 410
GALLATIN R NR GATEWAY
GLGM8N MAY-SEP 355 86 466 299 410
GALLATIN R NR GATEWAY
LOGM8 MAY-SEP 408 112 557 331 364
GALLATIN R AT LOGAN
LOGM8N MAY-SEP 537 109 666 471 495
GALLATIN R AT LOGAN
TOSM8N MAY-SEP 2364 115 2903 1992 2062
MISSOURI R AT TOSTON
FBNM8N MAY-SEP 3884 123 4653 3348 3171
MISSOURI R AT FORT BENTON
VRGM8N MAY-SEP 4426 126 5471 3818 3523
MISSOURI R NR VIRGELLE
LDKM8N MAY-SEP 4677 125 5950 4043 3739
MISSOURI R NR LANDUSKY
FPKM8N MAY-SEP 5036 128 6527 4341 3943
MISSOURI R BLW FT PECK DAM
AGSM8N MAY-SEP 583 196 738 529 298
GIBSON RESERVOIR INFLOW
SHLM8N MAY-SEP 393 130 517 311 301
MARIAS R NR SHELBY
HLWM8N MAY-SEP 104 126 145 71 82
MUSSELSHELL R AT HARLOWTON
YLOW4 MAY-SEP 623 101 722 552 617
YELLOWSTONE R AT YELLOWSTONE LK
YLOW4N MAY-SEP 742 117 869 630 634
YELLOWSTONE R AT YELLOWSTONE LK
CORM8 MAY-SEP 1549 111 1801 1333 1400
YELLOWSTONE R AT CORWIN SPRINGS
CORM8N MAY-SEP 1744 113 2037 1492 1539
YELLOWSTONE R AT CORWIN SPRINGS
LIVM8 MAY-SEP 1802 112 2095 1562 1607
YELLOWSTONE R AT LIVINGSTON
LIVM8N MAY-SEP 2058 114 2397 1784 1805
YELLOWSTONE R AT LIVINGSTON
BILM8 MAY-SEP 3372 120 3952 2970 2818
YELLOWSTONE R AT BILLINGS
BILM8N MAY-SEP 4002 109 4603 3585 3669
YELLOWSTONE R AT BILLINGS
MILM8N MAY-SEP 6454 102 7969 5603 6325
YELLOWSTONE R AT MILES CITY
SIDM8N MAY-SEP 6720 102 8341 5831 6596
YELLOWSTONE R AT SIDNEY
BTMM8 MAY-SEP 239 97 283 209 247
BOULDER R AT BIG TIMBER
BTMM8N MAY-SEP 280 97 323 250 288
BOULDER R AT BIG TIMBER
SRAM8 MAY-SEP 495 109 582 434 455
STILLWATER R NR ABSAROKEE
SRAM8N MAY-SEP 538 104 624 477 514
STILLWATER R NR ABSAROKEE
BFYM8 MAY-SEP 499 108 601 440 461
CLARKS FK YELWSTONE R NR BELFRY
BFYM8N MAY-SEP 557 105 658 500 529
CLARKS FK YELWSTONE R NR BELFRY
STXM8N MAY-SEP 2115 93 2691 1696 2284
BIGHORN R NR ST XAVIER
HRDM8N MAY-SEP 71 85 103 62 84
LITTLE BIGHORN R NR HARDIN
DAYW4N MAY-SEP 66 86 98 56 76
TONGUE R NR DAYTON
DSLM8N MAY-SEP 160 83 238 135 194
TONGUE R NR DECKER
DKRM8N MAY-SEP 161 82 241 135 195
TONGUE R RESERVOIR INFLOW
MHDM8N MAY-SEP 153 92 217 118 167
POWDER R NR MOORHEAD
LOCM8N MAY-SEP 165 90 237 130 183
POWDER R NR LOCATE
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
