April 1, 2019 Spring and Summer Streamflow Forecasts
Upper Missouri Basin
The high elevation snow pack in the Upper Missouri Basin as of April 1
was near to above average. The snow pack above Fort Peck, Montana was
113 percent. The snow pack in the St. Mary Basin was 91 percent, and the
Milk River Basin was 150 percent.
March precipitation across the Upper Missouri Basin was below average.
Basin precipitation summaries for the Missouri Basin include: Milk St. Mary,
32 percent; Milk Canada, 37 percent; Lower Milk, 28 percent; above Toston,
66 percent; Toston to Ft. Peck, 52 percent.
March 2019 Upper Missouri Mean Precip Oct-Mar WY2019 Upper Missouri Mean Precip
Stream flow in the Upper Missouri Basin is forecast to be
near to below average during the upcoming Spring and Summer.
The St. Mary River is forecast to have 76 percent of average
April-September flows. Runoff is expected to range around
97 percent of average for the Missouri Basin above Fort Peck,
Montana.

Upper Missouri April 1, 2019 Spring and Summer Streamflow Forecasts
Of the four major irrigation reservoirs in Montana; Lima
Reservoir had 154 percent average storage, Clark Canyon was
holding 120 percent of average water, Gibson Reservoir had 36
percent of average stored water, and Fresno Reservoir had
105 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; 99 and 122 percent of average water, respectively.
Yellowstone Basin
The high elevation snow pack in the Yellowstone Basin was near to above average
on April 1. The snow pack in the Upper Yellowstone Basin was 110 percent
of average. The snow packs in the Wind, Bighorn, and Shoshone Basins were 100,
89, and 101 percent of average, respectively. The snow packs in the Tongue
and Powder basins were 76 and 87 percent of average, respectively.
Precipitation during March was below average. The upper Yellowstone
River Basin received 55 percent of average precipitation while the
Lower Yellowstone River Basin reported 44 percent of average. The
Bighorn Basin received 66 percent of average precipitation while the
Wind River Basin received 102 percent of average. The Little Bighorn -
Upper Tongue Basin received 45 percent of average and the Powder River
had 84 percent of average precipitation.
March 2019 Yellowstone Mean Precip Oct-Mar WY2019 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
94 percent of average. Flow in the Tongue Basin is expected to be
77 percent of average. Flows in the Powder River are expected
to be about 96 percent of average.
Monthend storage at Boysen Reservoir was 109 percent of average.
Stored water in Buffalo Bill Reservoir was 99 percent of average.
Monthend storage was 124 percent of average at Bighorn Reservoir.

Yellowstone April 1, 2019 Spring and Summer Streamflow Forecasts
Platte Basin
The high elevation snow pack in the Upper North Platte Basin was
115 percent of average on April 1. The snow pack in the North Platte
Basin below Seminoe Reservoir was 129 percent of average. The snow
pack in the South Platte Basin was 112 percent of average.
Precipitation during March in the Upper North Platte Basin was 157
percent of average. In the Lower North Platte Basin, precipitation
was 143 percent of average. The North Platte Plains below Guernsey
Reservoir had 204 percent. The South Platte Mountains had 132
percent whereas the Plains had 264 percent of average March
precipitation.


March 2019 Platte Mean Precip Oct-Mar WY2019 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 94 percent of average. Streams in the South Platte
Basin above South Platte, Colorado can expect 96 percent
of average flow. For the remainder of the South Platte
basin, flows are expected near 88 percent.
Stored water in the South Platte Basin was 101 percent of average
on April 1.
North Platte Streamflow Fcst South Platte Streamflow Fcst
WATER SUPPLY FORECAST
NWS MISSOURI BASIN RIVER FORECAST CENTER
PLEASANT HILL MISSOURI
1005 CDT TUESDAY APRIL 02 2019
DATA CURRENT AS OF: APRIL 01 2019
MISSOURI/YELLOWSTONE/PLATTE RIVER BASIN FORECASTS
50% % 10% 90% AVG
PERIOD (KAF) AVG (KAF) (KAF) (KAF)
------------------------------------------------------------------
BOYSEN RESERVOIR INFLOW APR-SEP 717 68% 1237 458 1046
SBDW4N
BIGHORN R AT KANE APR-SEP 1113 68% 1783 719 1633
LVEW4N
GREYBULL R NR MEETEETSE APR-SEP 130 55% 204 71 235
MEEW4N
BUFFALO BILL RESERVOIR INFLOW APR-SEP 565 83% 724 435 679
CDYW4N
ST MARY R NR BABB APR-SEP 316 75% 381 260 418
SMYM8N
ST MARY R AT INT BOUNDARY APR-SEP 373 77% 465 308 485
SMBM8N
MILK R NR CUTBANK APR-SEP 14 37% 46 6 39
PDBM8N
MILK R AT EASTERN CROSSING APR-SEP 30 43% 103 13 70
ERNM8N
NORTH PLATTE R NR NORTHGATE APR-SEP 376 122% 554 287 308
NGTC2
ENCAMPMENT R NR ENCAMPMENT APR-SEP 132 90% 177 102 147
ERCW4
ENCAMPMENT R NR ENCAMPMENT APR-SEP 141 90% 186 111 156
ECRW4N
ROCK CK NR ARLINGTON APR-SEP 54 108% 64 43 50
KCRW4
ROCK CK NR ARLINGTON APR-SEP 55 108% 65 43 50
KCRW4N
SEMINOE RESERVOIR INFLOW WY APR-SEP 860 104% 1186 649 825
SETW4
SEMINOE RESERVOIR INFLOW WY APR-SEP 1017 104% 1339 800 981
SETW4N
LARAMIE R NR WOODS APR-SEP 61 84% 106 36 73
WODW4
LARAMIE R NR WOODS APR-SEP 96 89% 141 69 108
WODW4N
LITTLE LARAMIE R NR FILMORE APR-SEP 59 109% 75 47 54
SMTW4
LITTLE LARAMIE R NR FILMORE APR-SEP 61 109% 77 49 56
SMTW4N
ANTERO RESERVOIR INFLOW APR-SEP 15 95% 21 12 16
ANRC2N
SPINNEY MOUNTAIN RES INFLOW APR-SEP 56 109% 77 36 51
SPYC2N
ELEVENMILE CANYON RES INFLOW APR-SEP 64 113% 84 42 56
EVNC2N
CHEESMAN LAKE INFLOW APR-SEP 114 109% 177 82 105
CHEC2N
SOUTH PLATTE R AT SOUTH PLATTE APR-SEP 195 104% 299 155 188
SPTC2N
BEAR CK AT MORRISON APR-SEP 14 78% 32 8 18
MRRC2N
CLEAR CK AT GOLDEN APR-SEP 93 75% 141 75 124
GLDC2N
ST VRAIN CK AT LYONS APR-SEP 78 86% 127 67 91
LNSC2N
BOULDER CK NR ORODELL APR-SEP 45 91% 65 37 50
OROC2N
S BOULDER CK NR ELDORADO SPR APR-SEP 26 69% 43 18 38
BELC2N
CACHE LA POUDRE AT CANYON MOUTH APR-SEP 219 109% 322 153 201
FTDC2N
LIMA RESERVOIR INFLOW APR-SEP 36 61% 58 22 60
LRRM8N
CLARK CANYON RESERVOIR INFLOW APR-SEP 106 78% 162 77 137
CLKM8N
BEAVERHEAD R AT BARRETTS APR-SEP 131 77% 189 100 170
BARM8N
RUBY R RESERVOIR INFLOW APR-SEP 75 87% 95 58 86
ALRM8N
BIG HOLE R NR MELROSE APR-SEP 537 107% 787 436 504
MLRM8
BIG HOLE R NR MELROSE APR-SEP 593 106% 844 493 561
MLRM8N
HEBGEN RESERVOIR INFLOW APR-SEP 493 125% 551 418 393
HBDM8N
ENNIS RESERVOIR INFLOW APR-SEP 813 116% 945 705 699
ELMM8N
GALLATIN R NR GATEWAY APR-SEP 368 80% 481 300 460
GLGM8
GALLATIN R NR GATEWAY APR-SEP 368 80% 481 300 460
GLGM8N
GALLATIN R AT LOGAN APR-SEP 408 90% 598 336 454
LOGM8
GALLATIN R AT LOGAN APR-SEP 543 95% 720 475 575
LOGM8N
MISSOURI R AT TOSTON APR-SEP 2502 98% 3334 189 2556
TOSM8N
MISSOURI R AT FORT BENTON APR-SEP 3706 96% 5126 293 3865
FBNM8N
MISSOURI R NR VIRGELLE APR-SEP 4135 95% 5731 657 4346
VRGM8N
MISSOURI R NR LANDUSKY APR-SEP 4541 100% 6366 931 4532
LDKM8N
MISSOURI R BLW FT PECK DAM APR-SEP 5355 111% 7252 673 4815
FPKM8N
GIBSON RESERVOIR INFLOW APR-SEP 274 78% 464 221 350
AGSM8N
MARIAS R NR SHELBY APR-SEP 273 64% 438 199 428
SHLM8N
MUSSELSHELL R AT HARLOWTON APR-SEP 79 72% 137 53 110
HLWM8N
YELLOWSTONE R AT YELLOWSTONE LK APR-SEP 696 106% 825 592 657
YLOW4APR
YELLOWSTONE R AT YELLOWSTONE LK APR-SEP 880 107% 1021 751 824
YLOW4N
YELLOWSTONE R AT CORWIN SPRINGS APR-SEP 1591 95% 1981 347 1673
CORM8
YELLOWSTONE R AT CORWIN SPRINGS APR-SEP 1867 98% 2268 606 1911
CORM8N
YELLOWSTONE R AT LIVINGSTON APR-SEP 1848 97% 2308 567 1913
LIVM8
YELLOWSTONE R AT LIVINGSTON APR-SEP 2185 99% 2663 880 2208
LIVM8N
YELLOWSTONE R AT BILLINGS APR-SEP 3196 97% 4245 711 3302
BILM8
YELLOWSTONE R AT BILLINGS APR-SEP 4064 94% 5097 542 4313
BILM8N
YELLOWSTONE R AT MILES CITY APR-SEP 6474 91% 8280 355 7109
MILM8N
YELLOWSTONE R AT SIDNEY APR-SEP 6769 92% 8785 683 7331
SIDM8N
BOULDER R AT BIG TIMBER APR-SEP 210 77% 293 179 273
BTMM8
BOULDER R AT BIG TIMBER APR-SEP 252 80% 334 221 314
BTMM8N
STILLWATER R NR ABSAROKEE APR-SEP 412 83% 522 348 495
SRAM8
STILLWATER R NR ABSAROKEE APR-SEP 469 85% 579 407 552
SRAM8N
CLARKS FK YELWSTONE R NR BELFRY APR-SEP 457 93% 601 369 490
BFYM4
CLARKS FK YELWSTONE R NR BELFRY APR-SEP 529 94% 671 442 563
BFYM4N
BIGHORN R NR ST XAVIER APR-SEP 1961 82% 2857 475 2383
STXM8N
LITTLE BIGHORN R NR HARDIN APR-SEP 131 126% 207 90 104
HRDM8N
TONGUE R NR DAYTON APR-SEP 71 87% 100 50 81
DAYW4N
TONGUE R NR DECKER APR-SEP 150 68% 233 102 220
DSLM8N
TONGUE R RESERVOIR INFLOW APR-SEP 152 68% 236 102 222
DKRM8N
POWDER R NR LOCATE APR-SEP 177 90% 392 112 197
MHDM8
POWDER R NR LOCATE APR-SEP 235 107% 535 158 219
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