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 2014 Precipitation:
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:
Basin-wide Snow Water Equivalent (SWE) Percent of Normal:
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 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.
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:
Last Month 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
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 November 18, 2014:
The high terrain of the Upper Colorado River Basin (UCRB) experienced some beneficial snowfall over the past week which took a chunk out of the deficits in seasonal snowpack to date, but snowpack is still below average. Snowpack in the Upper Colorado is generally between 60 and 90% of normal now. Arctic air lead to a below-average week for the UCRB temperature-wise with some area of exception in the southwest part of the region.
East of the divide precipitation was moderate in the mountains and foothills (0.50-1.00") and minimal out on the plains (0.01-0.10"). Temperatures were well below normal after being hit with several rounds of arctic air over the course of the week.
Streamflows have been dropping across the UCRB this week, but remain near normal. Reservoirs continue to be in great shape in northern Colorado and Wyoming, but are far from full further south.
Status Quo: If snowpack stays low over the next few weeks as streamflows continue to diminish this area will be subject to degradations, but if conditions continue to improve as they have over the past week there would be no need for such degradations. It is still very early in the cold season.
Status Quo: Southeastern Colorado is being watched closely. The last week was cold with precipitation, so degradations wouldn't be prudent this week. Precipitation is expected to be below normal for the region the next two weeks, but the 8-14 day temperature outlook also shows increased probability of cold air anomalies, so water losses should be lessened. We will be very interested in ground reports of winter wheat productivity and dust storms (if they occur).