FGUS75 KGJT 121856 ESFGJT COC007-029-033-037-045-051-053-067-077-081-083-085-091-097-103- 107-111-113-UTC009-019-037-047-191900- Water Supply Outlook National Weather Service Grand Junction CO 1256 PM MDT Tue Mar 12 2024 ...SPRING FLOOD AND WATER RESOURCES OUTLOOK FOR WESTERN COLORADO AND EASTERN UTAH AS OF MARCH 12 2024... Hydrologic Service Area (HSA) ----------------------------- The Grand Junction HSA falls almost entirely within the Upper Colorado River Basin, which, ultimately, serves a population of over 40 million people water across the southwestern US. This service area encompasses seven basins including; the Upper Green River Basin and the Duchesne River Basin in eastern Utah, and the Yampa and White River Basins, Upper Colorado River Mainstem, Gunnison River Basin, Dolores and San Miguel River Basins, and the Upper San Juan River Basin in western Colorado. Each river and their tributaries feed the Colorado River above Lake Powell, and are primarily fed by snowpack accumulation along the Rocky Mountains (typically) from November - April. As the snow melts in the spring, the Upper Colorado River Basin begins to fill lakes, rivers, streams, reservoirs and trans-basin diversions spread as far as Denver to Los Angeles. Thus, seasonal water supply outlooks across the Grand Junction HSA are crucial for water management in order to support the needs for a vast population through hydropower, agricultural, municipal and recreational purposes. Flood & Water Supply Outlook Summary: ------------------------------------- The potential for spring flooding due to snowmelt is low at this time, and season water supply volumes remain below to near normal for the Upper Colorado River Basin. Currently, the following sites are forecast to have mean daily peak flows at or above the listed threshold at the given exceedance level: Exceedance Value Segment Threshold (probability) --------- --------- ------------- Elk-Milner Flood 10 Yampa-Deerlodge Flood 10 Green-Jensen Bankfull 50 Yampa-Maybell Bankfull 50 Eagle-Gypsum Bankfull 25 Yampa-Steamboat Springs Bankfull 10 Colorado-Cameo Bankfull 10 East-Almont Bankfull 10 Gunnison-Grand Junction Bankfull 10 Colorado-CO-UT Stateline Bankfull 10 San Juan-Pagosa Springs Bankfull 10 Forecast volumes, attm, are expected to range near normal due to average precipitation and snowpack accumulated thus far. April-July Water Supply Volume Forecasts: March 1 ------------------------------------------------- Green River 75-95% Duchesne 90-115% Yampa/White 90-105% Upper CO Mainstem 85-115% Gunnison 85-150% Dolores/San Miguel 60-95% San Juan 60-75% NOTE: In normal years, additional snowpack can accumulate in the mountains through the first half of April. However, it's worth noting that precipitation, strong winds and blowing dust, a cold spring or unseasonably warm spring during the snowmelt season can greatly affect total runoff volume and timing of peak flow. Observed Precipitation & Snowpack --------------------------------- Below normal precipitation in December into early January led to a slow start to the water year's total precipitation. Fortunately, a more active pattern returned to the Western Slope by mid January. These series of storms brought relief to winter's snowpack, and resulted in above average precipitation for the month of January. Storms continued to accumulated snow into the beginning of February, rising the total 2024 water year precipitation to near normal conditions across most high elevation basins by the end of the month. Basin snowpack conditions for the period (Percent of Median) October 1 2023 to March 1 2024: ------------------------------------------------------------ Subbasin Snow Precip -------- ---- ------ Green River 90 100 Duchesne 110 100 Yampa/White 110 110 Upper CO Mainstem 95 100 Gunnison 84 95 Dolores/San Miguel 85 85 San Juan 85 80 Soil Moisture ------------- An abnormally high spring runoff in 2023 improved soil moisture conditions and even removed the entire HSA from the US Drought Monitor by June. However, a delayed monsoon in the heat of summer led to increasing evaporation/ evapotrasporation, especially across southwest Colorado high elevations. As a result, soil conditions worsened and dropped below normal by Fall (November). Conditions decrease from north to south, with southwest Colorado mountains dropping below 50 percent of normal in some areas. Antecedent soil moisture can impact the efficiency of early spring runoff, and thus, water supply forecasts such that; basins with above average soil moisture tend to experience more efficient runoff from rainfall and snowmelt while basins with below average antecedent conditions show less efficient runoff until soil saturation is reached. Numerical Reservoir & River Outlooks: ------------------------------------- Table 1: Status of Reservoir Storage for WFO Grand Junction Reservoirs Period Ending: February 28, 2024 Figures are in 1000 Acre Feet ================================================================================================ C U R R E N T Y R L A S T Y R 1991-2020 EOM % of % of EOM % of FEB 28 Usable Storage Average Capacity Storage Average Avg Storage Capacity ------------------------------------------------------------------------------------------------ GUNNISON - BLUE MESA | 561.8| 112| 68|| 296.4| 59|| 499.4| 827.9| ------------------------------------------------------------------------------------------------ GUNNISON - CRYSTAL RE| 10.2| 66| 58|| 16.6| 107|| 15.6| 17.5| ------------------------------------------------------------------------------------------------ CRAWFORD RESERVOIR | 6.7| M| 48|| 2.4| M|| M| 14.1| ------------------------------------------------------------------------------------------------ FRUIT GROWERS DAM - A| 2.3| M| 51|| 2.4| M|| M| 4.5| ------------------------------------------------------------------------------------------------ FLORIDA - LEMON RESER| 15.7| 87| 40|| 17.1| 94|| 18.2| 39.8| ------------------------------------------------------------------------------------------------ DOLORES - MCPHEE RESE| 292.1| 113| 77|| 184.2| 71|| 257.8| 381.1| ------------------------------------------------------------------------------------------------ GUNNISON - MORROW POI| 116.2| 107| 99|| 107.6| 99|| 109.1| 117.0| ------------------------------------------------------------------------------------------------ MUDDY CK - PAONIA RES| 2.9| 96| 17|| 1.1| 38|| 3.0| 16.7| ------------------------------------------------------------------------------------------------ UNCOMPAHGRE - RIDGWAY| 65.5| 96| 79|| 69.9| 103|| 67.9| 83.0| ------------------------------------------------------------------------------------------------ RIFLE CK - RIFLE GAP | 12.6| M| 104|| 4.5| M|| M| 12.2| ------------------------------------------------------------------------------------------------ FRYING PAN - RUEDI RE| 73.2| 109| 72|| 63.3| 94|| 67.4| 102.0| ------------------------------------------------------------------------------------------------ CIMARRON - SILVER JAC| 1.6| 30| 12|| 1.9| 36|| 5.2| 13.0| ------------------------------------------------------------------------------------------------ TAYLOR - TAYLOR PARK | 70.5| 105| 66|| 64.1| 95|| 67.2| 106.2| ------------------------------------------------------------------------------------------------ LOS PINOS - VALLECITO| 66.7| 97| 53|| 74.7| 109|| 68.5| 125.4| ------------------------------------------------------------------------------------------------ GREEN - FLAMING GORGE| 3106.6| 101| 83|| 2457.3| 80|| 3062.9| 3749.0| ------------------------------------------------------------------------------------------------ COLORADO - LAKE POWEL| 7935.1| 56| 33|| 5319.8| 38|| 14153.2| 24322.0| ------------------------------------------------------------------------------------------------ T O T A L S | 12318.2| 67| 41|| 8673.8| 47|| 18395.4| 29931.5| Table 2: Mean Daily Peak Flow Forecasts (CFS) ID Location FORECAST DATE 90% 75% 50% 25% 10% -------------------------------------------------------------------------------- STMC2 Steamboat Spgs 2024-03-05 2501 2988 3311 3977 4568 ENMC2 Milner 2024-03-05 2965 3360 3888 4831 6107 MBLC2 Maybell 2024-03-05 7842 9901 11333 12110 16242 LILC2 Lily 2024-03-05 3093 3314 3987 5022 6333 YDLC2 Deerlodge Park 2024-03-05 10543 12472 15252 16838 21121 WRMC2 Meeker 2024-03-05 1971 2174 2494 2934 3644 WATU1 Watson 2024-03-05 1928 2220 2491 2907 3682 SLFC2 Slater 2024-03-05 599 657 729 896 1085 LSRC2 Slater 2024-03-05 1440 1586 1917 2292 2952 FISC2 Fish Ck-Upper 2024-03-05 423 504 627 712 914 ELHC2 Hayden 2024-03-05 907 1059 1134 1328 1721 WIKC2 Hamilton 2024-03-05 1137 1484 1791 2045 2736 WTRU1 Whiterocks 2024-03-05 325 374 564 671 816 ASHU1 Vernal 2024-03-05 357 455 616 758 973 SKEC2 Montezuma 2024-03-05 288 314 357 432 492 RCYC2 Redstone 2024-03-05 1159 1270 1447 1585 1885 CSSC2 Minturn-Cross Ck2024-03-05 303 346 378 457 526 GRVC2 Vail 2024-03-05 650 812 892 1072 1441 PSBC2 State Bridge 2024-03-05 399 488 584 651 814 ALEC2 Almont 2024-03-05 1405 1613 1808 2104 2662 ACSC2 Anthracite Ck 2024-03-05 1452 1679 1896 2281 3083 SCCC2 Cedaredge 2024-03-05 53 75 102 133 197 TRAC2 Taylor Park 2024-03-05 403 470 544 638 726 OHOC2 Gunnison 2024-03-05 331 389 442 524 642 DCKC2 Ridgway 2024-03-05 36 58 72 89 127 UCRC2 Ridgway 2024-03-05 524 605 681 804 927 LFGC2 Gateview 2024-03-05 875 1029 1178 1381 1556 COWC2 Cow Creek 2024-03-05 250 287 329 458 677 DRRC2 Rico 2024-03-05 443 551 665 733 830 DOLC2 Dolores 2024-03-05 1206 1424 1895 2163 2516 SMPC2 Placerville 2024-03-05 625 774 849 961 1094 LCCC2 Dolores 2024-03-05 64 76 112 148 204 PSPC2 Pagosa Springs 2024-03-05 1171 1477 1677 2010 2600 LPHC2 Hesperus 2024-03-05 107 132 163 184 237 PIDC2 Arboles 2024-03-05 955 1095 1292 1431 1886 ANBC2 Silverton 2024-03-05 96 1080 1236 1465 1559 VNBC2 Bayfield 2024-03-05 488 619 673 812 905 Table 3: Special Mean Daily Peak Flow Forecasts (cfs) LOCATION FLOOD FCST FORECAST FLOWS FLOW DATE 90% 75% 50% 25% 10% -------------------------------------------------------------------------------- GREEN - JENSEN, NR 24100 2024-03-01 14300 15800 18400 20000 24000 GREEN - GREEN RIVER, UT 37000 2024-03-01 16000 17500 21500 24500 30000 EAGLE - GYPSUM, BLO 6000 2024-03-01 2000 2450 2800 3500 4400 COLORADO - DOTSERO, NR 17000 2024-03-01 4500 5500 7000 9000 11500 ROARING FORK - GLENWOOD S 13000 2024-03-01 3000 3500 4000 4500 5500 COLORADO - CAMEO, NR 26000 2024-03-01 8500 10500 12500 15500 20000 GUNNISON - GRAND JUNCTION 20524 2024-03-01 5000 7500 8000 8000 10500 COLORADO - CO-UT STATE LI 46000 2024-03-01 11500 16500 19500 23000 31000 COLORADO - CISCO, NR 55000 2024-03-01 13000 18000 21000 25000 33000 SAN JUAN - BLUFF, NR 36000 2024-03-01 2700 3100 3700 4200 4700 COLORADO - CATARACT CANYO -999 2024-03-01 27000 34000 41000 49000 62000 Climatological Outlook and Forecast Conditions ---------------------------------------------- The current ENSO phase remains as El Nino Advisory, however, a La Nina Watch is now in effect. Above-average sea surface temperatures (SST) continued through February, though SST anomalies have weakened. As such El Nino conditions are present but are expected to transition to ENSO-neutral in the Northern hemisphere by April - June (79% chance), with La Nina potentially developing by June - August (55% chance). Based on current trends, the CPC's Seasonal Outlook for March - May maintains warmer than normal temperatures most likely across the PacNW and likely above normal precip focused over the southeast. Thus, western Colorado and eastern Utah fall well within the "Equal Chance" sector this Spring for both temperature and precipitation. On a shorter-scale timeframe, model guidance indicates a Rex Block develops over the Western CONUS by the end of the week, and persisting for several days. If this pattern holds, a low displaced over the Four Corners region would maintain cooler than normal temperatures and likely unsettled weather. CPC's 8-14 Day Outlook reflects this possibility, with above normal temperatures hugging the Pacific Coast, less so over the Four Corners region, and a swath of above normal precipitation from the SoCal coast into Western Colorado. -------------------------------------------------------------------- - Visit the Colorado Basin RFC for water supply and river forecasts at: cbrfc.noaa.gov. - Visit the Natural Resources Conservation Service for additional snowpack and reservoir data at: nrcs.usda.gov/programs-initiatives/sswsf-snow-survey-and-water- supply-forecasting-program - Visit our website for local weather, climate and river data at: weather.gov/gjt - Visit the Climate Prediction Center for sub-seasonal to seasonal outlooks, ENSO patterns and additional climate information at: cpc.ncep.noaa.gov $$