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:

  • The northern portion of the UCRB was dry over the past week with much of the area receiving less than 0.25" over the 7 day period. 
  • Farther south in the UCRB saw more precipitation over the week with the San Juan mountains picking up 0.11-2".  The lower elevations around the four corners and eastner Utah were drier, receiving less than 0.25".
  • The high country in Colorado received good moisture over the week.  The areas farther to the south received more rain, mainly between 0.26-2.00".  Isolated areas in Teller/El Paso saw over 2" over the week.  The northern and central mountains received between 0.25-1.00".
  • East of the divide also saw good moisture farther to the south on the plains in drought stricken areas.  The SE plains saw good moisture on the order of 0.26-2.00".  The highest amounts fell in El Paso, Pueblo, Huerfano, Las Animas, and Baca counties.
  • Farther to the north (mainly N of I-70) on the Plains saw lesser amounts of moisture over the week and mainly totaled less than 0.26".  Sedgwick and Phillips counties did pick up slightly more on the order of 0.26-1.00".

June Precipitation :

  • June was dry across much of the UCRB.  The Northern portion of the basin wasn't quite as dry with above average moisture falling across Sublette, Lincoln and Uinta counties in Wyoming.  Farther south was much below average for the month of June.  The Four Corners region saw less than 10% of normal for June.
  • Western Colorado and the headwaters of the CO river were also dry for the month with widespread areas receiving less than 70% of normal precipitation for June.
  • East of the divide, the NE plains of Colorado benefitted from convective thunderstorms.  The NE plains saw widespread above average moisture conditions for June.  The SE plains did not benefit as much as the NE plains and the rains were spottier.   The SE plains had widespread <70% of normal for the month with isolated areas in Pueblo, Kiowa, Prowers and Baca receiving above average moisture. 

Water Year Precipitation (Oct-June):

  • For the water year, Much of the UCRB remains in above average moisture since October 1 with the exception of Sweetwater county in WY and the Duchesne basin in Utah which have received <90% of normal for the water year.
  • The Four Corners area is also dry for the water year through June with lower elevations reporting <90% of normal precipitation for the water year.
  • East of the divide, the NE plains are reporting above average moisture for the water year while the SE plains remain dry at the longer time scale.  Widespread precipitation <70% of normal has been seen in SE Colorado where drought conditions persist.

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):

  • The short term SPI is slightly dry to slightly wet in the northern portion of the UCRB with SPI's between +1 and -1.  Farther to the south in the UCRB SPI's are drier from Mesa county south to the four corners.  The SPI's in that area range from +1 down to -2.  The driest SPI's are being reported along the Colorado River in San Juan county Utah. 
  • The northern and central mountains are near normal with SPI's between +1 and -1.
  • East of the divide, the NE plains are reporting SPI's between +1 and -3.  Sedgwick 5S is reporting a very low SPI and reported very little precipitation over the past month. 
  • The southeastern plains are showing mainly wet SPI's and range from +2 to -1.5.  The lowest values are in western Lincoln (Limon) and Baca counties (Walsh).

Long Term (6-month):

  • The UCRB is showing mainly dry SPI's.  In the northern portion of the basin, they range from +1 to -2.  The driest SPI's are in NE Utah and Fremont county Wyoming.  The high country in Colorado are showing mainly wet SPI's in the northern basins.
  • The southern portin of the UCRB shows more variation over the long term with SPI's ranging from +1 to -2.  The driest areas are around the four corners. 
  • East of the divide shows wetter conditions on the NE plains and drier on the SE plains over the longer term.  The NE plains are mainly reporting SPI's between +1.5 to -1 while the SE plains range from +1 to -1.5.  The driest SPI is being reported in Baca county (Walsh). 

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:

  • 77% of the gages in the UCRB are reporting above the 25th percentile (normal and above) for 7-day average streamflow.
  • 23% of the gages are reporting below the 25th percentile with only 1% on the record low category. 
  • The lowest streamflows are in the Duchesne basin in NE Utah where percentiles are in the much below normal category below the 10th percentile.
  • Streamflow on the Colorado River near the CO-UT state line remains in the normal range and reporting in the 67th percentile (98% of average).
  • The Green River at Green River, UT is reporting in the 34th percentile (60% of average).
  • The San Juan River near Bluff, UT has dropped back into the below normal range and reporting in the 11th percentile (20% of average) after an increase from monsoonal moisture. 

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.

VIC:

  • The driest region of the UCRB from the modeled soil moisture product extends from Sweetwater county in Wyoming SE into the Duchesne basin in Utah.  That area shows widespread soil moisture percentiles below the 20th percentile.  Central Sweetwater and eastern Duchesne/western Uintah counties in Utah are reporting soil moisture below the 2nd percentile.
  • The four corners area is reporting soil moisture from the 10th-30th percentile.
  • East of the divide whows wet soils on the NE plains and near normal soil moisture farther to the south.  Southern Lincoln county is reporting soil moisture mainly between the 20th and 30th percentiles and is the driest area on the plains according to the VIC model. 
  • Farther south in Huerfano/Costilla and Las Animas counties are reporting soil moisture above the 70th percentile.

VegDRI:

  • The VegDri product is showing very dry vegetation in the Upper Green river basin in Wyoming and Duchesne river basin in Utah, similar to many other products.  This area ranges from moderate to severe as depicted by VegDRI
  • The four corners is also indicating dry vegetation conditions in pre- to moderate drought category.
  • Much of the high country in Colorado is showing near normal vegetation conditions.
  • East of the divide shows more near normal conditions along the Front Range and foothills but dries out farther east.
  • The area east of about Lincoln county is reporting vegetation in the pre- to moderate drought categories.  The driest areas are Cheyenne county south to Baca and west into Las Animas county.  Sedgwick county is also reporting dry vegetation conditions.

Reservoirs:

  • Flaming Gorge is 101% of the July average and volumes are decreasing.
  • Green Mtn is 106% of July average and volume continues to increase.
  • Lake Granby is 117% of July average and volume continues to increase.
  • Lake Dillon is 102% of July average and volume is decreasing.
  • Blue Mesa is 93% of the July average and volume is increasing.
  • Navajo is 80% of the July average and showing volume increases since last month.
  • McPhee is 75% of average and volume is decreasing. 

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 is tracking right along normal for the growing season.
  • Cortez: ET has been tracking slightly below average for the growing season.
  • Center: ET has ramped up and is now tracking above normal for the season since the beginning of June. 
  • Avondale: Station down, data out of date.
  • Idalia: ET dropped in mid-July with monsoonal moisture coming into the area.  ET has again ramped up but is still tracking slightly below normal for the growing season to date.
  • Holyoke: Similar to Idalia, ET dropped off in mid-July and continues to track below average for the growing season.
  • Lucerne: ET rates are tracking along the seasonal average this growing season.


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 mostly saw temperatures 0-6 degrees above average over the past week. The northern portion of the basin was 0-4 degrees above average while farther south was warmer with temperatures 2-6 degrees above normal for the week. 
  • East of the divide was very warm with temperatures 2-8 degrees above normal.  The warmest areas were near the KS/NE border from Sedgwick south to Baca county where temperatures were 6-8 degees above normal.  Farther west on the plains was still warm with temperatures 2-6 degrees above normal.

 

Last Month Temperatures:

  • Temperatures in the southern part of the UCRB basin were slightly above normal and temperatures in the northern and eastern parts of the basin were slightly cooler than normal. 
  • East of the basin temperatures did not stray far from seasonal normals either. South WY and northeast CO show mainly between 0 and 2 degrees below normal.
  • South and southeastern CO saw the warmest June temperatures. Most of Huerfano, Las Animas, and Pueblo Counties showed temperatures 2 to 4 degrees above normal. 
  • Most of southeastern CO recorded temperatures 0 to 4 degrees above normal for the month of June. Otero and Bent Counties were the most above normal in the region. 

FORECAST AND OUTLOOK

The top two images show Climate Prediction Center's Precipitation outlooks for 8 - 14 days (top left) and 3 months (top right). 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:

  • Today and tomorrow (Tues/Wed) much of Colorado and Eastern Utah are under a flash flood watch as monsoonal moisture is forecast to enter the area bringing numerous showers and thunderstorms which are capable of producing flash flooding. 
  • 5 day QPF values maximize over the mountain and foothills in Colorado where up to 4.1" of precipitation is forecast for the 5 day period.  The UCRB is mainly forecast to receive <1.00" over the 5 day period.
  • The highest amounts also extend SE onto the plains in Colorado where moisture is still very much needed in the drought stricken areas.  That area is forecast to see 1.00-2.50" for the 5 day period.
  •  The forecast dries out toward the weekend but with lingerning moisture, chances for thunderstorms will remain in the afternoons. 
  • Current forecasts show another surge of monsoonal moisture Sunday into Monday next week.

Longer Term:

  • The 8-14 day precipitation outlook shows chances of above average precipitation for the UCRB and all of Colorado. 
  • The 8-14 day temperature outlook (not pictured) shows increased chances for below average temperatures over much of the UCRB and all of Colorado.
  • The CPC 3-month outlook shows higher chances for wetter than normal conditions over the UCRB in Utah, Colorado, and Wyoming for the late July-mid October time period.
  • The seasonal drought outlook indicates no areas in the UT, WY, or CO where drought is anticipated to develop or intensify. Drought conditions are likely to improve in UT due to the combination of El Nino development and the North American Monsoon. In drought-stricken SE-CO drought is likely to continue, but improve. 
  • Drought in the Four Corners region is anticipated to continue, but improve. 

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 29 July 2014:

Conditions were dry over the northern portion of the UCRB for the past week while areas to the south were a bit wetter in the San Juan mountains. 

East of the divide saw good moisture on the SE plains while things were a bit drier on the NE plains. 

 

Recommendations:

UCRB

In conjunction with Tony Bergantino's recommendations, Sweetwater county in Wyoming and portions of Moffat in Colorado and Daggett in Utah are suggested to be degraded from D0 to D1 as dryness continues in that area. This is supported by both the VegDRI and VIC models since there is little station data in the area. 

Eastern Plains

The odd D3 shape on the border of Baca/Las Animas counties in SE Colorado is suggest to be improved from D3 to D2.  That area again received 1-2" of moisture over the past week.  Month to date totals in that area are 2-4" with portions of western Baca receiving 4-6" since the beginning of the month.