The images above use daily precipitation statistics from NWS COOP, CoCoRaHS, and CoAgMet stations. From
top to bottom, and left to right: most recent 7-days of accumulated precipitation in inches; current month-to-date
accumulated precipitation in inches; last month's precipitation as a percent of average;
water-year-to-date precipitation as a percent of average.
Additional Precipitation Links: (will take you to an outside website)
High Plains Regional Climate Center's ACIS Maps
The top two images show Climate Prediction Center's Precipitation and Temperature outlooks for 8 - 14 days. The middle image shows the 3 months Precipitation outlook. The bottom left image shows the Weather Prediction Center's Quantitative
Precipitation Forecast accumulation for the seven days between Tuesday 12Z and ending Tuesday 12Z. The
bottom right image shows the Climate Prediction Center's most recent release of the U.S. Seasonal
Short Term: (5/10)
- Today and tomorrow afternoon showers are possible for southeast Colorado and the urban corridor, but the UCRB should stay mostly dry.
- A drying trend will set in later this week with Thursday through Saturday afternoon looking mostly clear for the basin and eastern Colorado.
- Saturday into Sunday a change is expected in the weather with an upper level trough moving into the region bringing cooler temperatures and raising the probability of precipitation.
- Precipitation totals for the upcoming week are expected to be highest east of the Continental Divide, and in the Upper Green River Basin with upslope flow developing Sunday into early next week. The southern portion of the UCRB will be mostly dry. Totals in western Colorado are forecast to range from 0.10-0.50" for the week to come, a fairly typical week.
- The 8-14 day precipitation outlook shows increased chances for above average precipitation in the northern half of the Upper Colorado River Basin and northern Colorado. The southern half of the UCRB and southern Colorado will have equal chances of above and below average precipitation.
- The 8-14 day temperature outlook shows increased chances for below average temperatures for the Upper Colorado river Basin. These chances are most strongly enhanced in the western and central portions of the basin. Eastern Colorado has equal chances of above and below average temperatures.
- The Climate Prediction Center May through July outlook shows increased chances of above average precipitation for the entirety of the UCRB and eastern Colorado.
- The seasonal drought outlook for Colorado and the UCRB shows no likely drought development over the next three months, and removal likely in the southeast corner of the state.
Above is the most recent release of the U.S. Drought Monitor map for the UCRB region.
the proposed changes for this week, with supporting text.
Summary: May 31, 2016
Last week, the Upper Colorado River Basin received below average precipitation over most of the basin. The western portion of the Upper Green River basin was the only area in the UCRB that saw normal precipitation. The rest of the basin received less than 0.50 inches last week. Even with this dry week, May should end with above normal precipitation in the basin. Even with the wet month, the Four Corners area is still showing dry SPIs in the 0 to -1 range for 90-day time scale justifying the current D0.
The wet month has brought cooler than normal temperatures and lower than average reference evapotranspiration. Soils and vegetation through most of the basin is showing normal to moist conditions with dryness around the Duchesne Basin.
Streamflow through the basin is still mostly in the normal range thanks to the current snowmelt. A few areas showing lower flows show up in the Duchesne basin and the headwaters of the Gunnison basin where snowpack was lower. The three integrator (Colorado River at CO-UT stateline, Green River at Green River, UT, San Juan River at Bluff, UT) sites in the basin are currently in the normal range for the 7-day average streamflow, seeing a small decrease with the dry weather. The Water Year cumulative streamflow for the three sites are seeing near normal accumulations.
Eastern Colorado saw a week of above normal precipitation over much of the area. From Weld County down to Pueblo County and east, precipitation amounts were at least 0.50 inches, with a large area in east-central Colorado seeing up to 4.00 inches. The rest of eastern Colorado saw less than 0.50 inches, with much of southeastern Colorado receiving less than 0.25 inches last week. May precipitation is mostly near normal, with a few drier areas popping up in southeastern Colorado and near the Denver Metro area. 30-day SPIs in these two areas are in the 0 to -1 range, however they bump back up to the 0 to +1 range on the 90-day time.
With the late season snowfall along the east slope, snowpack ended above normal and the current melting of the snowpack is keeping eastern Colorado streamflows at or above normal.
Over all of eastern Colorado temperatures for the past week and month to date have been below normal, which is keeping reference evapotranspiration at lower than normal levels for the growing season to date. Soils and vegetation are also in the normal range over most of eastern Colorado.
UCRB: Status quo.
Eastern Colorado: Status quo.
**Disclaimer: The above recommendations are recommendations only, based on data, impacts, and
input from local experts. These recommendations are sent to the U.S. Drought Monitor author on Tuesdays. The USDM author
has sole discretion on final changes made in the region and can accept, reject, or modify the above recommendations
and may have additional modifications. Additionally, any recommendations discussed during the NIDIS webinars that are agreed upon
by the local experts and USDM author are still subject to change. Changes are final and official as of Thursday
morning, and can be viewed on the official U.S. Drought Monitor website.
Additional Drought Index Links: (will take you to an outside website)
Palmer Drought Severity Index for Climate Divisions Updated Weekly
WestWide Drought Tracker's PDSI Updated Monthly
Surface Water Supply Index