Summary: May 12, 2020
Dryness prevailed through most of the Intermountain West region in April. Much of western and southern Colorado saw the driest or one of the driest Aprils on record. Northern Utah also got in on the extreme dryness that was April 2020 with the Salt Lake area seeing some of their lowest April precipitation amounts on record. For both Utah and Colorado, this was an inopportune time to see this much dryness since April is still a wetter month of the year. Continuing with the dry theme of the week, eastern Colorado started off the growing season with much below normal precipitation. Some wetter spots in the IMW region included north-central Colorado, northwestern Wyoming, and parts of Arizona and New Mexico, see normal or above-normal precipitation.
The second week of May has seen the dry pattern continue with the exception of northern Wyoming, central Arizona and northeastern New Mexico, all seeing about 0.51-1.20” of precipitation. The rest of the IMW saw little to no precipitation.
Typically by this time of year the snowpack season is in full snowmelt form with the occasional May storm that brings a pause to melt and a small increase in the snowpack. This means we have passed the peak snowpack of the year. Most of the IMW saw near normal peaks, with many on the lower end of normal. With little snow in April and a quick warmup, the snowpack is melting quickly.
The quick snowmelt means streamflows are starting to come up. Most of the streams with above normal flows means the snow is melting quicker and earlier than normal. We are seeing above normal flows in the headwaters of the Colorado River and the Yampa River. However, we are also seeing below normal flows on the White, Colorado, Gunnison, San Miguel, and San Juan Rivers. Our three main sites are barely in the normal flow range.
The IMW saw a split in temperatures over the second week of May. Utah, Arizona, New Mexico and western Colorado saw above average temperatures with the highest temps in southwestern Arizona where they experienced 10-15 degrees above normal. Eastern Colorado and Wyoming, on the other had, experienced below average temperatures this last week with the coolest temperatures of 9-12 degrees below average seen in northeastern Wyoming.
Little to no precipitation is forecast to occur over the next week for Colorado, Arizona and New Mexico. The regions with the highest probability of precipitation is northern Wyoming and Utah. The 8-14 day outlook is showing below average temperatures for much of the region except eastern Wyoming and Colorado with a decent chance of precipitation for northern Wyoming and northeastern Colorado with Utah, Arizona and New Mexico being dry.