Summary: February 21, 2017
It was another warm week for the Upper Colorado River Basin and eastern Colorado. Temperatures were 6-12 degrees above normal for most of the basin with some pockets closer to normal in southwest Wyoming and in southern Utah near Lake Powell. Temperatures were 6-12 degrees above normal for southeast Colorado, and 12-18 degrees above normal for northeast Colorado as cold winter air continues to be confined at higher latitudes.
The first part of the week was relatively calm with westerly winds returning to the basin last Friday through the weekend. This allowed for some precipitation in the basin, but mainly just wind east of the divide save for some spotty showers on Sunday night. The high elevations of the UCRB managed 0.25-0.50" of precipitation over the last week for the most part. Some of the lower-to-middle elevation areas, such as La Plata County and eastern Montezuma County in Colorado, and northern Emery County and Carbon County in Utah, received 0.50-1.00" or more.
Despite the unseasonably warm weather, high elevation snowpack is still well above average for most areas across the basin and east of the divide. Snowpack in eastern Utah and southwest Wyoming is particularly high. The Yampa Basin and North Park areas in northwest Colorado are closer to average.
The unseasonably warm weather has led to increased snowpack oblation at lower and middle latitudes of the Upper Colorado River Basin, and thawing of river channels. This, and a wet January, have paved the way for higher than average flows in the UCRB. 45% of non-frozen gages are reporting in the above normal range, and 23% are reporting much above normal. Lake Powell is still storing less water than its climatological average for this time of year. Other major reservoirs in the basin are reporting storage in the normal, or above normal range. Navajo Reservoir has seen an early upswing in storage this year, and is now at 104% of average storage. Soil moisture remains a concern for eastern Colorado as spring rains will be needed to make up for deficits during the second half of last growing season.
After a month of well above average temperatures for most of the basin, a substantial cool-down appears to be on the way, and forecast models are indicating that the cooler weather may stick around for a while once it hits (see outlook for details). The storm appears to be most likely to make the UCRB richer with widespread totals of over an inch forecast across the Tetons, Wasatch, Uintahs, and western Colorado for the next week. Unfortunately, it could make eastern Colorado poorer as this storm will likely be more of a wind event out on the plains.
UCRB: Status Quo. No drought here.
Eastern Colorado: It is recommended that D2 be extended in western Lincoln County to include southern and central Lincoln County. Karval is showing similar long-term deficits to Limon, and reports on the ground have verified a gradient in conditions between Karval and Rocky Ford. Conditions are still on the dry side for Rocky Ford, but not as bad as immediately north.
It is recommended that D0 be removed from the Sangre De Cristo Range on the border of Saguache and Custer County. SNOTEL stations in this area have shown lower water year to date precipitation percentiles than their nearby counterparts, but have caught up into the normal range. Snowpack here is also above average.
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