May 1, 2023 Spring and Summer Streamflow Forecasts
Upper Missouri Basin
The high elevation snow pack in the Upper Missouri Basin as of May 1
was near average. The snow pack in the St. Mary Basin was 94 percent,
and the Milk River Basin was 97 percent.
April precipitation across the Upper Missouri Basin was below average.
Basin precipitation summaries for the Missouri Basin include: Milk St. Mary,
64 percent; Milk Canada, 53 percent; Lower Milk, 80 percent; above Toston,
88 percent; Toston to Ft. Peck, 98 percent.
April 2023 Upper Missouri Mean Precip Oct-Apr WY2023 Upper Missouri Mean Precip
Stream flow in the Upper Missouri Basin is forecast to be
below to above average during the upcoming Spring and Summer.
The St. Mary River is forecast to have 47 percent of average
May-September flows. Runoff is expected to range around
110 percent of average for the Missouri Basin above Fort Peck,
Montana.
Upper Missouri May 1, 2023 Spring and Summer Streamflow Forecasts
Of the four major irrigation reservoirs in Montana; Lima
Reservoir had 58 percent average storage, Clark Canyon was
holding 86 percent of average water, Gibson Reservoir had 43
percent of average stored water, and Fresno Reservoir had
102 percent of average stored water.
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 133,
106, and 95 percent of average, respectively. The snow packs in the Tongue
and Powder basins were 105 and 110 percent of average, respectively.
Precipitation during April was below average. The upper Yellowstone River
Basin received 62 percent of average precipitation while the Lower
Yellowstone River Basin reported 55 percent of average. The Bighorn
Basin received 59 percent of average precipitation while the
Wind River Basin received 117 percent of average. The Little Bighorn -
Upper Tongue Basin received 73 percent of average and the Powder River
had 52 percent of average precipitation.
April 2023 Yellowstone Mean Precip Oct-Apr WY2023 Yellowstone Mean Precip
Forecast stream flow in the Yellowstone Basin is below to above average
for the upcoming Spring and Summer. Stream flow for the
Yellowstone River above Sidney, Montana is forecast to be about
83 percent of average. Flow in the Tongue Basin is expected to be
122 percent of average. Flows in the Powder River are expected
to be about 57 percent of average.
Monthend storage at Boysen Reservoir was 92 percent of average.
Stored water in Buffalo Bill Reservoir was 102 percent of average.
Monthend storage was 100 percent of average at Bighorn Reservoir.
Yellowstone May 1, 2023 Spring and Summer Streamflow Forecasts
Platte Basin
The high elevation snow pack in the Upper North Platte Basin was
91 percent of average on May 1. The snow pack in the North Platte
Basin below Seminoe Reservoir was 125 percent of average. The snow
pack in the South Platte Basin was 106 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 91 percent of average. The North Platte Plains below Guernsy
Reservoir had 59 percent. The South Platte Mountains had 76
percent whereas the Plains had 66 percent of average April
precipitation.
April 2023 Platte Mean Precip Oct-Apr WY2023 Platte Mean Precip
Stream flow in the Platte Basin is forecast to be below
to above average during the upcoming Spring and Summer. Runoff
for streams above Seminoe Reservoir are expected to be
about 120 percent of average. Streams in the South Platte
Basin above South Platte, Colorado can expect 65 percent
of average flow. For the remainder of the South Platte
basin, flows are expected near 70 percent.
Stored water in the South Platte Basin was 96 percent of average
on May 1.
North Platte Streamflow Fcst South Platte Streamflow Fcst
FGUS63 KKRF 081910
ESPKRF
WATER SUPPLY FORECAST
NWS MISSOURI BASIN RIVER FORECAST CENTER
PLEASANT HILL MISSOURI
1402 CDT MONDAY MAY 08, 2023
DATA CURRENT AS OF: MAY 01, 2023
MISSOURI/YELLOWSTONE/PLATTE RIVER BASIN FORECASTS
50% % 10% 90% AVG
FORECAST POINT PERIOD (KAF) AVG (KAF) (KAF) (KAF)
--------------------------------------------------------------------
Boysen Resvr Inflow Apr-Sep 551 77 907 347 720
SBDW4
Boysen Resvr Inflow Apr-Sep 917 103 1337 679 890
SBDW4N
Bighorn R at Kane Apr-Sep 817 83 1525 593 985
LVEW4
Bighorn R at Kane Apr-Sep 1441 100 2215 1091 1440
LVEW4N
Greybull R at Meeteetse Apr-Sep 161 82 257 119 196
MEEW4
Greybull R at Meeteetse Apr-Sep 161 79 257 119 205
MEEW4N
Buffalo Bill Resvr Inflow Apr-Sep 501 61 652 413 815
CDYW4
Buffalo Bill Resvr Inflow Apr-Sep 572 63 717 489 910
CDYW4N
St. Mary R nr Babb Apr-Sep 257 56 315 216 460
SMYM8
St. Mary R nr Babb Apr-Sep 256 48 315 214 535
SMYM8N
St. Mary R at Intl Boundary Apr-Sep 181 46 264 130 390
SMBM8
St. Mary R at Intl Boundary Apr-Sep 297 45 380 250 660
SMBM8N
Milk R nr Western Crossing Apr-Sep 9 8 28 6 113
PDBM8
Milk R nr Western Crossing Apr-Sep 15 37 37 10 41
PDBM8N
Milk R nr Eastern Crossing Apr-Sep 141 66 218 130 215
ERNM8
Milk R nr Eastern Crossing Apr-Sep 54 48 159 37 112
ERNM8N
North Platte R nr Northgate Apr-Sep 414 169 536 328 245
NGTC2
North Platte R nr Northgate Apr-Sep 463 157 583 378 295
NGTC2N
Encampment R nr Encampment Apr-Sep 193 124 222 170 156
ECRW4
Encampment R nr Encampment Apr-Sep 203 122 231 180 166
ECRW4N
Rock Cr nr Arlington Apr-Sep 50 94 57 43 53
KCRW4
Rock Cr nr Arlington Apr-Sep 50 94 57 43 53
KCRW4N
Seminoe Resvr Inflow Apr-Sep 1123 147 1365 917 765
SETW4
Seminoe Resvr Inflow Apr-Sep 1286 140 1538 1094 920
SETW4N
Laramie R nr Woods Landing Apr-Sep 75 69 110 50 108
WODW4
Laramie R nr Woods Landing Apr-Sep 108 76 143 84 142
WODW4N
Little Laramie R nr Filmore Apr-Sep 60 109 73 49 55
SMTW4
Little Laramie R nr Filmore Apr-Sep 62 109 75 51 57
SMTW4N
Antero Resvr Inflow Apr-Sep 9 64 12 6 14
ANRC2
Antero Resvr Inflow Apr-Sep 9 64 12 6 14
ANRC2N
Spinney Mountain Resvr Inflow Apr-Sep 40 70 58 31 57
SPYC2
Spinney Mountain Resvr Inflow Apr-Sep 30 67 49 20 45
SPYC2N
Elevenmile Canyon Resvr Inflow Apr-Sep 35 59 45 30 59
EVNC2
Elevenmile Canyon Resvr Inflow Apr-Sep 33 66 53 21 50
EVNC2N
Cheesman Lk Inflow Apr-Sep 55 55 78 41 100
CHEC2
Cheesman Lk Inflow Apr-Sep 58 62 93 39 93
CHEC2N
S Platte R at S Platte Apr-Sep 245 102 281 230 240
SPTC2
S Platte R at S Platte Apr-Sep 108 53 163 75 205
SPTC2N
Bear Cr at Morrison Apr-Sep 10 38 19 6 26
MRRC2
Bear Cr at Morrison Apr-Sep 10 38 19 6 26
MRRC2N
Clear Cr at Golden Apr-Sep 78 66 99 63 118
GLDC2
Clear Cr at Golden Apr-Sep 89 68 110 73 131
GLDC2N
St. Vrain Cr at Lyons Apr-Sep 41 52 64 31 79
LNSC2
St. Vrain Cr at Lyons Apr-Sep 63 58 89 50 109
LNSC2N
Boulder Cr nr Orodell Apr-Sep 24 51 38 20 47
OROC2
Boulder Cr nr Orodell Apr-Sep 39 75 54 34 52
OROC2N
S Boulder Cr nr Eldorado Sprgs Apr-Sep 22 63 28 18 35
BELC2
S Boulder Cr nr Eldorado Sprgs Apr-Sep 22 55 34 18 40
BELC2N
Cache La Poudre at Canyon Mouth Apr-Sep 203 188 280 164 108
FTDC2
Cache La Poudre at Canyon Mouth Apr-Sep 239 114 324 196 210
FTDC2N
Lima Resvr Inflow Apr-Sep 205 270 249 172 76
LRRM8
Lima Resvr Inflow Apr-Sep 205 259 249 172 79
LRRM8N
Clark Canyon Resvr Inflow Apr-Sep 141 128 200 115 110
CLKM8
Clark Canyon Resvr Inflow Apr-Sep 280 141 340 239 198
CLKM8N
Beaverhead R at Barretts Apr-Sep 184 92 192 178 199
BARM8
Beaverhead R at Barretts Apr-Sep 315 112 380 274 280
BARM8N
Ruby R Resvr Inflow Apr-Sep 86 98 102 65 88
ALRM8
Ruby R Resvr Inflow Apr-Sep 86 89 102 65 97
ALRM8N
Big Hole R nr Melrose Apr-Sep 615 103 824 543 595
MLRM8
Big Hole R nr Melrose Apr-Sep 679 103 889 604 660
MLRM8N
Hebgen Resvr Inflow Apr-Sep 479 103 552 440 465
HBDM8
Hebgen Resvr Inflow Apr-Sep 479 103 553 440 465
HBDM8N
Ennis Resvr Inflow Apr-Sep 721 101 842 651 715
ELMM8
Ennis Resvr Inflow Apr-Sep 825 113 948 755 730
ELMM8N
Gallatin R nr Gateway Apr-Sep 464 98 571 399 475
GLGM8
Gallatin R nr Gateway Apr-Sep 464 98 571 399 475
GLGM8N
Gallatin R at Logan Apr-Sep 445 88 581 368 505
LOGM8
Gallatin R at Logan Apr-Sep 604 93 733 541 650
LOGM8N
Missouri R at Toston Apr-Sep 2026 98 2546 1823 2060
TOSM8
Missouri R at Toston Apr-Sep 3002 106 3541 2781 2830
TOSM8N
Missouri R at Fort Benton Apr-Sep 2408 79 3070 2174 3060
FBNM8
Missouri R at Fort Benton Apr-Sep 4601 112 5351 4242 4100
FBNM8N
Missouri R nr Virgelle Apr-Sep 2638 77 3347 2369 3420
VRGM8
Missouri R nr Virgelle Apr-Sep 5023 110 5942 4635 4560
VRGM8N
Missouri R nr Landusky Apr-Sep 2919 79 3594 2552 3680
LDKM8
Missouri R nr Landusky Apr-Sep 5356 110 6270 4933 4890
LDKM8N
Missouri R below Fort Peck Dam Apr-Sep 3186 83 3883 2757 3840
FPKM8
Missouri R below Fort Peck Dam Apr-Sep 5684 110 6603 5203 5180
FPKM8N
Gibson Resvr Inflow Apr-Sep 365 81 494 309 450
AGSM8
Gibson Resvr Inflow Apr-Sep 364 81 493 308 450
AGSM8N
Marias R nr Shelby Apr-Sep 221 51 354 160 435
SHLM8
Marias R nr Shelby Apr-Sep 269 55 397 200 490
SHLM8N
Musselshell R at Harlowton Apr-Sep 60 75 94 36 80
HLWM8
Musselshell R at Harlowton Apr-Sep 74 78 106 50 95
HLWM8N
Yellowstone R at Yellowstone Lk Apr-Sep 666 82 717 568 815
YLOW4
Yellowstone R at Yellowstone Lk Apr-Sep 823 98 912 702 840
YLOW4N
Yellowstone R at Corwin Sprgs Apr-Sep 1532 77 1762 1306 1980
CORM8
Yellowstone R at Corwin Sprgs Apr-Sep 1789 86 2030 1550 2070
CORM8N
Yellowstone R at Livingston Apr-Sep 1702 74 2006 1468 2290
LIVM8
Yellowstone R at Livingston Apr-Sep 2026 83 2329 1768 2440
LIVM8N
Yellowstone R at Billings Apr-Sep 2767 68 3432 2440 4070
BILM8
Yellowstone R at Billings Apr-Sep 3718 78 4385 3362 4790
BILM8N
Yellowstone R at Miles City Apr-Sep 4167 71 5464 3620 5850
MILM8
Yellowstone R at Miles City Apr-Sep 6435 84 7815 5685 7690
MILM8N
Yellowstone R at Sidney Apr-Sep 4296 75 5650 3642 5710
SIDM8
Yellowstone R at Sidney Apr-Sep 6892 86 8303 6062 8060
SIDM8N
Boulder R at Big Timber Apr-Sep 177 53 218 149 335
BTMM8
Boulder R at Big Timber Apr-Sep 218 58 258 191 375
BTMM8N
Stillwater R nr Absarokee Apr-Sep 343 64 428 294 540
SRAM8
Stillwater R nr Absarokee Apr-Sep 403 68 485 354 595
SRAM8N
Clks Fk Yellowstone R nr Belfry Apr-Sep 386 62 490 328 620
BFYM8
Clks Fk Yellowstone R nr Belfry Apr-Sep 460 66 561 402 695
BFYM8N
Bighorn R nr St. Xavier Apr-Sep 865 60 1616 784 1430
STXM8
Bighorn R nr St. Xavier Apr-Sep 2141 87 2986 1665 2460
STXM8N
Little Bighorn R nr Hardin Apr-Sep 73 57 149 59 127
HRDM8
Little Bighorn R nr Hardin Apr-Sep 74 58 149 59 127
HRDM8N
Tongue R nr Dayton Apr-Sep 56 58 79 42 96
DAYW4
Tongue R nr Dayton Apr-Sep 62 61 85 47 101
DAYW4N
Tongue R nr Decker Apr-Sep 250 106 339 217 235
DSLM8
Tongue R nr Decker Apr-Sep 295 123 384 262 240
DSLM8N
Tongue R Resvr Inflow Apr-Sep 250 106 342 218 235
DKRM8
Tongue R Resvr Inflow Apr-Sep 296 121 387 263 245
DKRM8N
Powder R at Moorhead Apr-Sep 127 56 279 108 225
MHDM8
Powder R at Moorhead Apr-Sep 154 57 314 129 270
MHDM8N
Powder R nr Locate Apr-Sep 203 78 397 174 260
LOCM8
Powder R nr Locate Apr-Sep 232 76 426 193 305
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 voulme as simulated by the river
forecast model considering acontinuous simulation of the basin
response to historic climate data (observed precipitation and
temperatures) over the period of 1991-2020.
The 50%, 10% and 90% columns indicate the probability that the
actual volume will exceed the forecast for the valid time period.
Beginning April 1, May and June official forecasts include observed
runoff volume up to official forecast date.
For more information, please visit: www.weather.gov/mbrfc/water
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