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.
Last Week Precipitation:
Water Year 2015 Precipitation (Oct-April):
SNOTEL AND SNOWPACK
The top left image shows the Natural Resources Conservation Service's SNOTEL water-year-to-date
precipitation percentile rankings. The top right image shows sub-basin averaged snow water
equivalent accumulations as a percent of average. The images below show accumulated snow water
equivalent in inches (green) compared to average (blue) and last year (red) for several different sub-basins
across the UCRB (and were created by the Colorado Basin River Forecast Center).
SNOTEL Precipitation Percentiles:
SWE Timeseries Graphs:
STANDARDIZED PRECIPITATION INDEX
Standardized Precipitation Index standardizes precipitation accumulations for a specified time period
into percentile rankings. -1.0 to -1.5 is
equivalent to a D1 to D2. -1.5 to -2.0 is equivalent to a D2 to D3. -2.0 and worse is equivalent to a D3 to
D4. 30- and 60-day SPIs focus on short-term conditions while 6- and 9-month SPIs focus on long-term
conditions. SPI data provided by High Plains Regional Climate Center.
Short Term (30-day):
Long Term (6-month):
The top left image shows 7-day averaged streamflows as a percentile ranking across the UCRB. The top
right image shows 7-day averaged discharge over time at three key sites around the UCRB: The Colorado
River at the CO-UT state line; the Green River at Green River, UT; and the San Juan River near Bluff,
UT. All streamflow data provided by United States Geological Survey.
The top left image shows VIC modeled soil moisture as a percentile ranking.
The top right image shows VIC plus SWE total soil moisture storage. The bottom image shows satellite-derived vegetation from the VegDRI product (which updates on Mondays).
The above image shows last month's and this month's current volumes of the major reservoirs in
the UCRB, with percent of average and percent of capacity.
|The above images are of reference evapotranspiration (ET) from CoAgMet sites across Colorado. Reference ET assumes the amount of water that will evaporate from a well-irrigated crop. Higher ET rates occur during hot, dry, and windy conditions. Lower ET rates are more desirable for crops. See a map of locations for the above ET sites.|
All images show temperature departures from average over different time periods (last 7 days on top
left; month-to-date on top right; last full month on bottom). Temperature departure
maps provided by HPRCC ACIS.
Last Week Temperatures:
FORECAST AND OUTLOOK
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 Hydrologic Prediction Center's Quantitative
Precipitation Forecast accumulation for the five days between Tuesday 12Z and ending Sunday 12Z. The
bottom right image shows the Climate Prediction Center's most recent release of the U.S. Seasonal
Short Term: (5/19)
Above is the most recent release of the U.S. Drought Monitor map for the UCRB region. Below shows
the proposed changes for this week, with supporting text.
Summary for May 19, 2015:
It was yet another week of above average moisture and below average temperatures across the Upper Colorado River Basin and the eastern plains of Colorado, and the forecast continues to call for more. Basin-wide SPI's are all positive with some areas that are currently classified as D2 seeing 30-day SPI's as high as +2. This needs to be balanced against a winter of poor snowpack leading to a water supply drought across the Upper Colorado River Basin. SPIs on the 6-month timescale are still below average in the Wasatch Range. Many SNOTEL stations in the Wasatch and Uintah Ranges are still at or near record lows to date out of at least a 15 year record. Streamflows in the region are still forecast to peak well below average. Many improvements will be recommended this week, but they will be measured against the long-term drought.
UCRB: A downgrade from D3 to D2 is recommended for northeast Jaub County. Drought conditions persist in the area, but recent moisture has brought it out of extreme drought.
It is recommended that the southern flank of D2 be downgraded to D1 in the San Juan Region following a week of heavy rains for the area. This recommendation would cut all D2 along the southern border of Utah and southwest CO. The cut would be made from about the border of San Juan and Otero county extending westward through central San Miguel County and then dipping southward to keep north central Dolores County in D2.
It is recommended that D2 be downgraded to D1 in northeast Utah, Northwest Colorado, and in central Utah at lower elevations. The Wasatch and Uintah Mountain Ranges are still in pretty bad shape following this year's snowpack, and the whole region is still in a water supply drought, but low elevations of northeast Utah and northwest Colorado now snow positive SPI's on timescales all the way back to a year. Vegetative heath and soil moisture conditions in this region do not reflect a severe drought.
Eastern CO: A one-category improvement is recommended across southeast Colorado from the Las Animas-Costilla County Line eastward. The recent and continuing rains in southeast Colorado may serve as the knockout punch to the long-term drought that has plagued the area since 2011. After yesterday's moisture the area has seen anywhere from 0.75-2.50" of rain over the past week, and it continues to fall. Lower temperatures and cloud cover have kept evaporative demand lower as well. SPI's are positive back to 6 months across the region, and modeled root zone soil moisture and vegetative health is being shown now as average or better.