#Monsoon2021, if it arrives, may underdeliver — The #GrandJunction Daily Sentinel #ColoradoRiver #COriver #aridification

From The Grand Junction Daily Sentinel (Dennis Webb):

Anything would be better than a “nonsoon,” but what monsoonal rains western Colorado may get this summer are looking like they’ll be below-average in terms of the total precipitation they deliver.

“If we do get a monsoon this year, right now the indications are, the models and the outlooks are that it would be a below-normal monsoon, so it’s something that maybe we shouldn’t rely on right now” in terms of relief from drought, Aldis Strautins, a hydrologist with the Grand Junction office of the National Weather Service, said Wednesday.

He was speaking during an online coordination meeting between reservoir operators, local irrigators, water utilities and others involved with managing and using water in the Colorado River basin in Colorado.

The region has gotten little in the way of summer monsoonal rain in recent years, adding to drought conditions and leading to the “nonsoon” references by some in the water community. So it might not take much monsoon rain this summer to be viewed as an improvement. But Strautins thinks the models and outlooks call for tempering expectations…

There is a high chance that monsoonal precipitation will develop over the Southwest in the first week of July, according to the National Integrated Drought Information System. Strautins said the moisture that arrived in the area in recent days wasn’t necessarily monsoonal, as it came in from the west, but it did tap into some moisture from the south…

The federal Climate Prediction Center is saying there’s a higher probability of below-normal precipitation and above-normal temperatures in the combined period of July through September in Colorado. Those trends continue to be projected in outlooks as far out as November for Colorado, with much of the West looking like it could be drier-than-normal in the fall and the entire country looking like it could be warmer than average.

West Drought Monitor map June 22, 2021.

Dry conditions resulting in part from near-nonsoon conditions in the region last summer were followed by below-normal snowpack this winter, and much of the spring snowmelt got soaked up by parched soil rather than making it into waterways and reservoirs. Above-average temperatures only have aggravated the situation thanks to things like reservoir evaporation and increased demand for irrigation water, while increasing the likelihood of wildfires like those currently burning in western Colorado.

Cody Moser, a hydrologist with the Colorado Basin River Forecast Center, told those in Wednesday’s meeting that the Colorado River at Palisade was flowing at only 13% of its average for this time of year. The river’s peak runoff flows this year at Cameo reached 6,330 cubic feet per second on June 6, the fourth-lowest annual peak there on record.

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