Summary: June 27, 2017
It was another dry week across the UCRB with most of the region receiving no precipitation. A few areas on the eastern portion of the basin and higher elevations in ne Utah saw a few hundredths of an inch of precipitation. This rain most likely evaporated before it could be beneficial. June is a dry time of year for much of the UCRB, so the lack of precipitation this month is not uncommon. Although, add the current dry period to a dry end of the snow season starts to cause concern, hence the introduction of D0 in the past few weeks.
Temperatures were mainly up to 6 degrees above normal for the week. Areas in western Colorado and eastern Utah saw 100+ degree temperatures for a few days last week. These areas were up to 9 degrees above normal.
Despite the dryness, streamflows are still in the normal range for much of the UCRB with some of the headwaters streams above normal thanks to the melting snow that remains higher up. The 3 key streamgaging sites in the basin have been in the normal to above normal range, following the normal pattern during the snowmelt season.
Eastern Colorado saw common summertime rainfall patters, with areas being hit by storms; in Logan, Phillips, Washington and Yuma counties, and areas being missed by storms; along the Front Range including Elbert, portions of Lincoln, Kiowa, Bent and Otero counties. June has been dry for much of Northern Colorado down to the Palmer Divide. If it weren't for the May precipitation, we would be considering D0. The Vegetation Health Index is starting to show some drying vegetation and modeled soil moisture is starting to dry out in northeastern Colorado. Even with these showing some drying, conditions are still good enough for no category of dryness or drought at this time. This area will be monitored for possible D0 introduction if July continues to be dry.
For the past 30-days, SPIs for the entire region are on the dry side of the scale, except for areas that have been hit by summer thunderstorms. 90-day SPIs improve with the exception of our D0 area in western Colorado and eastern Utah. This pattern extends out to the 9-month SPI.
UCRB: Status quo. The current D0 seems appropriate. The valleys in Western Colorado and Utah have been drier since February and March with near normal precipitation in areas in May. If July continues to be dry through this area and in the higher elevations, D0 will be expanded.
Eastern Colorado: Status quo. Despite dryness in June, May precipitation was good enough to cover this dryness. If Northern Colorado continues to be dry, D0 will need to be considered.
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