PRECIPITATION

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:

  • Most of the UCRB was dry saw less than 0.50 inches over the last week, with a few higher totals.
  • The Upper Green River Basin in Wyoming saw less than 0.25" over much of the basin. Sweetwater County and Sublette County were below 0.10". Uinta County saw between 0.25 and 1.00", spilling down into Summit and Duchesne counties in Utah.
  • Northeast Utah was below half an inch over much of the area, with the exception of Summit and Duchesne counties.
  • Southeastern Utah was even drier with the area seeing less than 0.25" and San Juan County seeing less than 0.10".
  • Western Colorado saw better precipitation in the higher elevations with an area in the central mountains seeing between 0.50 and 1.00 inches, with a few spotty areas above 1.00".  Northwestern Colorado in Moffat, Rio Blanco and Garfield county saw less than 0.25".  The Four Corners was also dry, with less than 0.10".
  • The San Luis Valley saw a widespread swath of between 0.50" and 1.00" of moisture.  
  • East of the Divide, the best moisture was on the eastern plains. A line from eastern Weld county, south to Las Animas County mostly received greater than 0.50", with spots of greater than 1.00".  This precipitation did miss Pueblo, Crowley, and western Kiowa counties, with western Bent, eastern Otero and northern Las Animas counties receiving between 0.25 and 0.50".  Areas in Kit Carson, Cheyenne, eastern Kiowa, and Prowers counties saw up to 3.00", and an area in Prowers County above 3.00"
  • Douglass, Elbert and northern El Paso counties were the only areas along the Front Range that saw better than 0.25". 

June Precipitation:

  • June precipitation was not as widespread as May across Colorado and the Upper Colorado River Basin. 
  • The Upper Green River Basin in Wyoming received at or slightly above normal (100-150% of normal) precipitation in June.
  • Northeast Utah saw less precipitation, with the Wasatch Range seeing below normal precipitation, mainly in the 50-70% of normal range.  With Wasatch and Utah counties seeing less than 50% of normal.  The Duchesne Basin was mainly near normal, with higher elevations of the basin and southern Duchesne Basin seeing below normal precipitation (down to 50%).
  • Southeast Utah and southwest Colorado saw another wet month, seeing 300+ percent of normal through the area.  This included the Four Corners area and into the San Juan Range.
  • Southwestern Colorado in Moffat, Rio Blanco, Garfield, Grand and Routt Counties was dry, seeing less than 50% of normal over much of the area.  The rest of western Colorado saw at of above normal June precipitation.
  • East of the Divide, June precipitation was mostly at or above normal, with the Denver Metro area seeing 200 to 300+ percent of normal.  Larimer, Weld, Morgan, Logan, Phillips, Yuma and Baca counties saw drier than normal precipitation for the month of June.
  • The San Luis Valley also saw above average June precipitation.

Water Year 2015 Precipitation (Oct-June):

  • The May and early June precipitation helped many areas of the UCRB and Colorado recover nicely, however, there are still some dry spots showing up for the Water Year through June.
  • The Upper Green river basin is at or above normal. Eastern Uinta and Lincoln Counties have received over 300% of their normal water year to date precipitation.  Eastern Sweetwater County has seen up to 250% of the normal water year precipitation through June.  Sublette and central Sweetwater counties have seen at or slightly above normal precipitation.
  • Northeastern Utah has seen a mix of above and below normal precipitation.  The higher elevations of the Wasatch and Uintah ranges have seen below normal precipitation, mainly between 50-90% of normal.  While the lower elevations, especially in Duchesne, Uintah and Carbon counties, have seen up to 150% of normal.
  • Southeastern Utah is now showing at or above normal precipitation for the water year through June.
  • Western Colorado is still showing dryness in parts of Routt, Moffat, Rio Blanco, Garfield, Mesa and Gunnison counties, most areas seeing 50-90% or normal precipitation.
  • The San Juan mountains and along the divide are mostly above normal for the water year.
  • The Rio Grande Basin is now showing at or above normal precipitation for the water year through June.
  • Eastern Colorado is now above average for the water year to date across the area after the wet May and near normal June.  A few areas that had a drier June are showing closer to normal water year percent of normal, however these areas are still above normal.

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):

  • 30-day SPIs are still above normal, or well above normal for the UCRB.
  • The Upper Green River basin is showing SPIs slightly above normal between 0 and +1.
  • In northeast Utah most SPIs are between 0 and +1. There is one SPI between +1.5 and +2 in Duchesne County.
  • Southeast Utah is showing wet to very wet SPIs mostly between 0 and +2.5
  • Northwest Colorado SPIs is also above normal at the 30-day timescale. SPIs range from 0 to +2.5. 
  • All SPIs in southwest Colorado are between 0 and +2. 
  • SPIs across central Colorado are still above 0 all the way from the northern to the southern border. Jackson and Freemont Counties are showing SPIs between +1.5 and +2. 
  • Eastern Colorado is a bit drier on the 30-day timescale, with SPIs showing up in the 0 to -1 range in northeastern Colorado and in Pueblo, Crowley and Otero Counties.  The rest of the SPIs along the Front Range and east-central Colorado are between 0 and +1.5.

Long Term (6-month):

  • On the 6-month timescale, SPIs are wet for the UCRB with the exception of the far western border of the basin in central Utah.
  • The Upper Green has SPIs ranging from +1 to +2.5.
  • NE Utah shows most SPIs on the wet side, between 0 and +2.  The southern portion of the Wasatch Range in central Utah is drier showing SPIs between 0 and -1.5.
  • Southeast Utah is wet with SPIs between +1.5 and +3, with one station in Wayne County above +3.
  • Western Colorado is showing SPIs mostly between 0 and +2. Mesa County is between +1.5 and +2.5.
  • In central Colorado SPIs are exceptionally wet on the 6-month timescale. Most SPIs are in the +2 to >+3 range. 
  • Eastern Colorado, all SPIs are still wet on the 6-month timescale. They range from 0 to +2.5.
  • The Rio Grande basin is wet at the 6-month timescale with SPIs from +1.5 to +2.

STREAMFLOW


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.

Streamflow Statistics:

  • Streamflows across the UCRB are receeding, which is the seasonal norm, but continue higher than climatological averages in most locations.
  • 91% of the gages in the UCRB are reporting in the normal to much above normal range for 7-day average streamflow. There are no gages recording record high flows. 
  • Only 8% of the gages are recording below normal and 1% at much below normal for 7-day average streamflow.
  • Streamflow on the Colorado River near the CO-UT state line is now at the 89th percentile, 135% of average. 
  • The Green River at Green River, UT has dropped to the 35th percentile, 61% of average.
  • Streamflow at the San Juan near Bluff, UT is down to the 46th percentile, 55% of average. 

SURFACE WATER

The top left image shows VIC modeled soil moisture as a percentile ranking. The top right 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 graphs shown belo are plots of reservoir volumes over the past full year and current year to date (black). The dashed line at the top of each graphic indicates the reservoir's capacity, and the background color-coded shading provides context for the range of reservoir levels observed over the past 30 years. The data are obtained from the Bureau of Reclamation. Some of the reservoir percentiles don't line up at the new year due to differences in reservoir levels at the beginning of 1985 and the end of 2014.  Dead storage has been subtracted. Note: Lake Granby data are obtained from the Colorado Division of Water Resources, and only goes back to the year 2000.


VIC:

  • Soils are mostly in the average range in the Upper Green River Basin. The southeast portion of Sweetwater County is in the 10-30th percentile range. Far west Uinta and Lincoln Counties are above the 70th percentile. 
  • Soils in northeastern UT are mostly in the average with a couple dry patches remaining. The driest areas are in Duchesne and Uintah Counties where there are remaining patches of soil in the 10-30th percentile range. 
  • Southeast Utah is also showing soil moisture mostly in the normal range.  Southeast Emery County is showing a dry patch between the 10th and 30th percentile. Northeast San Juan and eastern Grand Counties are above the 70th percentile. 
  • Western CO soils are in the normal to above normal range. Most of Mesa, Garfield, Delta, Rio Blanco, and Montrose Counties are above the 70th percentile. Soil moisture is between the 90 and 98th percentile in central Mesa County. 
  • The San Juan Mountain Range is mostly above the 70th percentile. 
  • The San Luis Valley is mostly is showing some wet soils in the 70th to 80th percentile, with a normal area in central Saguache County.
  • The Upper Arkansas River Basin is holding onto some very wet soils. Much of Chaffee, Park, Lake, Freemont, and Custer Counties are showing soil moisture above the 90th percentile. 
  • The wettest remaining soils are mostly along the northern Front Range and Palmer Divide. Jefferson, Adams, Arapahoe, and Douglas Counties all still show soils above the 95th percentile. Soil moisture is above the 70th percentile all the way up and down the Front Range and Foot Hills in Colorado. 
  • Farther east out on the plains soils are primarily back in the normal range, but the southeast corner of the state is still holding enough water to remain in the 70-90th percentile range. 

VegDri:

  • The Upper Green River Basin shows mostly wet vegetative health conditions with some areas of pre to moderate drought along the northwest flank of the basin and Lincoln and Uinta Counties.
  • The Wasatch Mountains are showing pre to moderate drought, which looks a little better than it did a few weeks ago. The Uintah Mountains are still holding on to a fair amount of pre-drought, especially in the western portion of the range, but starting to show some wet conditions in the southern portion of the range. 
  • The VegDRI indicates a mixed bag of drought to moist conditions in the Duchesne River Basin, with we conditions in the basin.
  • In southeast Utah vegetative health is depicted primarily as moist vegetation showing up now.
  • Most of western Colorado is in the normal to slightly moist range. Pre-drought still prevails in western Moffat and Rio Blanco Counties. 
  • The San Luis Valley is showing moist vegetative health conditions.
  • Central Colorado is depicted as extremely moist. This includes Chaffee, Park, Teller, Fremont, and Custer Counties. This area of very moist vegetation extends onto the Front Range and into El Paso, Elbert, Douglas, Jefferson, Adams, and Arapahoe Counties. This has been the case for over a month now.
  • Northeastern Colorado is showing moist vegetation, with an area of pre-drought showing up Sedgwick, Phillips, Yuma and Washington counties. 
  • Southeast Colorado conditions are now mostly moist. Very isolated pre and moderate drought still is depicted in the far southeast corner of the state. 

Reservoirs:

  • Flaming Gorge is at 108% of its July average. 
  • Green Mtn is 106% of the July average.
  • Lake Granby is at 117% of its July average and 99% full.  Lake Granby has been releasing water to avoid spilling.
  • Blue Mesa is 114% of the July average, 97% full. 
  • Navajo is 104% of its July average. 
  • McPhee is now at 104% of its July average.
  • Lake Powell is now at 68% of the July average, 54% full.

EVAPOTRANSPIRATION



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.

Reference Evapotranspiration:

  • Olathe: ET started the growing season at higher than average ET rates and since mid May has been tracking below the lowest reference ET year of 1999.
  • Cortez: ET began a little above normal, but has been tracking below normal since early May.  Since the start of July, Reference ET has been nearing the lowest year of 1995.
  • Center: Early season ET was higher than the track taken during the record year, but has slowed considerably, and is now tracking below average. 
  • Avondale: ET began just above average, but has slowed to below normal.
  • Idalia: ET started near average and is now tracking along the record low ET year of 2009. 
  • Holyoke: ET started around normal and has dropped below normal since the second week of May. 
  • Lucerne: ET has been tracking lower than the previous record low year in 2009 since the second week of May.


TEMPERATURE

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:

  • The UCRB experienced another week of cooler than average temperatures.
  • The Upper Green Basin saw temperatures 2 to 4 degrees below normal along the eastern and northern portion of the basin, and 4 to 6 degrees below normal in the western portion.
  • Northeastern Utah experienced temperatures 4 to 6 degrees below normal in the northern Wasatch and Uintah Range. The southern Uintah Range and the Duchesne River Basin saw 2 to 4 degrees below normal temperatures.
  • Southeastern Utah was 4 to 6 degrees cooler than normal.
  • Northwest Colorado was 2 to 4 degrees cooler than normal, with some 4 to 6 degree cooler temperatures in western Mesa county.
  • Southwest Colorado was also 2 to 4 degrees cooler than normal over the last week. 
  • The San Luis Valley was primarily just 0 to 2 degrees cooler than normal over the past week. 
  • East of the Divide, the Front Range saw temperatures 0 to 2 degrees cooler than normal with the higher elevations in the northern mountains 2 to 4 degrees cooler than normal.
  • Northeastern Colorado was also 0 to 2 degrees cooler than normal from Logan, Washington, Arapahoe and northern Elbert counties.  South of this diagonal line in eastern and southeastern Colorado was 0 to 2 degrees warmer than normal, with an area in El Paso and most of Pueblo counties 2 to 4 degrees above normal.

June Temperatures:

  • The month of June saw above normal temperatures across the UCRB and Colorado.
  • Sublette, southern Lincoln and Uinta counties were 6 to 8 degrees above normal, with the rest of the Upper Green Basin and much of northern Utah 4 to 6 degrees above normal for the month.
  • The southern Wasatch Range saw temperatures 6 to 8 degrees above normal, while Grand and Emery counties were 2 to 4 degrees above normal, and San Juan County, Utah 0 to 2 degrees warmer than average.
  • Western Colorado was 2 to 4 degrees above normal for the month over most of the area.  Moffat and Rio Blanco counties, with a portion of Grand and Eagle counties 4 to 6 degrees above normal.
  • Southwestern Colorado saw a mix 0 to 2 degrees and 2 to 4 degrees above normal for June.
  • East of the Divide temperatures for the month of June were 0 to 4 degrees above normal, with areas in Weld, Adams, Arapaho and Elbert were 0 to 2 degrees above normal.  Portions of the middle Arkansas River Basin in southwest Colorado also saw 0 to 2 degrees above normal for June.

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 Drought Outlook.

Short Term: (7/28)

  • The next 5 to 7 days look to be dry for the northern portion of the basin in the Upper Green Basin and northern Utah.  Moisture will return to the UCRB and Colorado on Thursday.  Higher precipitation totals will be in the southern portion of the basin and southern Colorado.
  • Temperatures will be near to above normal over the next week through the area.

Longer Term:

  • The 8-14 day precipitation outlook shows increased chances for above normal precipitation for the entirety of the UCRB and Colorado east of the divide.
  • The 8-14 day temperature outlook shows increased chances for below normal temperatures for the majority of the UCRB and Colorado.  The east side of the basin and east of the Divide show the highest chances of cooler than normal temperatures.  The far western side of the basin show normal chances of above and below normal temperatures.
  • The Climate Prediction Center August through October precipitation outlook shows increased chances for above average precipitation across the entirety of the UCRB and Colorado east of the divide. These chances are maximized at low elevations in the southern portion of the basin. 
  • The seasonal drought outlook indicates that drought is expected to persist or intensify in the western portion of the UCRB through the end of October, but drought development is not likely for the eastern portion of the basin, nor for Colorado east of the divide. 

U.S. DROUGHT MONITOR

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 July 28, 2015:  

Another quite week across the Upper Colorado River Basin and Colorado.  Precipitation amounts in the basin for the last week were lower in the west side of the basin, and higher closer to the Continental Divide in the central Colorado Rockies.  Across the entire basin, temperatures were lower than normal, keeping the evaporation demand lower for another week.  Streamflows and reservoir levels through the basin are still at or above average, with the exception of Lake Powell.  SPIs in the basin across all time scales remain on the wet, above normal, side of the SPI scale, with the exception of the far western side of the basin in central Utah, with SPIs down to -1.5 on the longer term.

East of the Divide saw beneficial precipitation in the eastern plains and drier along the Foothills and Front Range.  Temperatures were slightly warmer than normal.  Like the UCRB, SPIs are mostly on the wet side of the scale, with the exception of northeastern Colorado and the middle portion of the Arkansas River Basin on the 30-day timescale.  These SPIs turn wet on all other timescales.

With the conditions in the basin and Colorado, no changes to the Drought Monitor are necessary.

Recommendations:

UCRB: Status Quo 

Eastern CO: Status Quo