• October and November temperatures were slightly above (1 degree) average.  December temperatures were 3 degrees below average for the  foothills and eastern plains, and near normal for the central mountains and western slope.  January 1-16, 2012 temperatures in northeastern Colorado were well above average ranging from 6 to 8 degrees Fahrenheit above average.
  
  
• December, 2011 precipitation was well above average for southeast Colorado ranging from 200 to 300% of normal while the central and western mountains experienced well below average moisture.
  
  
• Colorado Climate Center weather stations for the month of December report above average moisture conditions for Pueblo (125%), Walsh (205%), Burlington (117%), Fort Collins (130%), and Boulder (116%); average moisture conditions for Mesa Verde (104%) and Del Norte  (102%); and below average moisture conditions for Grand Lake (53%), Grand Junction (70%), Montrose (79%), Alamosa (73%), and Akron (81%).
  
  
• Drought conditions in Baca County in southeast Colorado have seen significant improvement over the last six weeks, however D2, severe drought conditions still remain in both Baca county as well as the San Luis Valley.  Elsewhere in the state abnormally dry conditions have emerged, with D0 now extending into the central and northern mountains all the way to the Wyoming and Utah borders.  Up to 36% of the state is now experiencing D0 conditions.
  
  
• As of January 17, 2012 61% of the state is now experiencing some level of drought classification, according to the U.S. Drought Monitor, a nearly 20% increase from previous weeks.  D4 has been entirely removed from Baca County and D3 has been significantly reduced.  However, D2, D1, and D0 conditions are impacting much of the rest of the state.  D0-D4 represents abnormally dry, moderate, severe, extreme and exceptional drought conditions respectively.

Statewide Water Conditions:

• October to December 2011 Total Water Year Precipitation for the State of Colorado is below average for all basins so far except for the Upper Rio Grande basin (104% of average), and the cumulative statewide average is currently at 78% of normal.
  
  
• Statewide reservoir storage is currently at 105% of average, and is good for all basins except for the Upper Rio Grande.  The Upper Rio Grande basin has the lowest reservoir storage level in the state at 64%.
  
  
• Mid-winter statewide snowpack is only at 66% of average so far, and ranges from a high of 87% of average in the Arkansas basin to a low of 60% of average in the Colorado and the Yampa/White/North Platte basins.
  
  
• The NRCS stream flow forecast for 2012 projects near average flow for streams within the Gunnison basin and San Miguel/Dolores/San Juan/Animas basin, and below average flow for streams within all other basins.
  
  
• The statewide Surface Water Supply Index (SWSI)* values for December (January 1, 2012) range from a high value of +1.5 in the South Platte Basin to a low value of -2.6 in the Yampa/White Basin.  Two of the basins (South Platte and Rio Grande) experienced no change from the previous month’s value, while the remaining five basins (Arkansas, Gunnison, Colorado, Yampa/White, and San Juan/Dolores) experienced a loss from the previous month’s value.  The western half of the state shows a dramatic contrast in SWSI value from last year at this time, due to December 2010’s significantly above average snowpack and this year’s lagging snowpack.
  
  
• *The SWSI is developed by the Colorado Division of Water Resources and the Natural Resources Conservation Service and is used as an indicator of mountain-based water supply conditions in the major river basins of the state.  It is based on stream flow, reservoir storage, and precipitation for the winter period of November through April (December 1 through April 1).  During the winter period, snowpack is the primary component in all basins except the South Platte basin where reservoir storage is given the most weight.  

Listed in the following table are reservoir storage and precipitation conditions as of January 18, 2012.  

Basin	Snow Pack (% of Average)	Reservoir Storage (% of average)	Total Water Year Precipitation (% of average)
South Platte	76%	112%	85%
Arkansas	82%	93%	89%
Upper Rio Grande	87%	64%	104%
San Miguel, Dolores, San Juans, Animas	70%	102%	90%
Gunnison	61%	104%	71%
Colorado	60%	112%	68%
Yampa, White, North Platte	60%	118%	64%
Statewide Conditions	66%	105%	78%

Forecast (copied from Klaus Wolter’s Executive Summary) January 18, 2012. 

• La Nina has made a come-back, confirming my long-lead statements from last year.  It is weaker than last year, and has not left the typical footprints of La Nina, such as drought in Texas – so far.  However, an overall drier season was anticipated based on 2nd year La Nina conditions for our mountain snowpack.
  
  
• Snowfall has been unusually anemic in north-central Colorado.  This does not bode well for our runoff season (42% variance of Colorado River runoff is related to fall moisture).  This week’s snow storm is hopefully just the opening salvo for a more typical La Nina storm track that will favor the mountains for at least another week or two.
  
  
• My latest forecast for January through March 2012 has reverted back to a mostly dry outlook for the southwestern U.S., including most of our mountain ranges, except for the eastern San Juan and Sangre de Cristo mountains.  The only region with a tilt towards  wetter conditions remains in northern New Mexico.  Northeastern Colorado is sitting this one out as in earlier editions of this forecast: the odds for either wet or dry conditions in the next three months are higher than for a near-normal outcome.
  
  
• Bottom line: Considering that 2nd year La Nina seasons are often drier than during the 1st year, the current outlook for January through March 2012 has reverted back to that overall scenario for much of our mountains.  Given the current deficit of 20-40% in our state’s snowpack, it would take an almost equally large positive anomaly to recover this lost ground by April 1st.  As best as I can estimate right now, the odds for this to occur are less than 10% (i.e., less than in most other years).  My current estimate for Colorado River runoff in 2012 is similar to two years ago when it ended up between 12-13 MAF for the naturalized flow.

Abbreviated Basin Updates (From Division of Water Resource’s Water Supply Conditions Report Dated November 2011):

S. Platte –  Reservoir storage for Dillon, Horsetooth, Eleven Mile, Cheeseman, Jackson, and Barr Lake reservoirs was 117% of normal as of the end of December.  Cumulative storage in the major plains reservoirs: Julesberg, North Sterling, and Prewitt, is at 91% of capacity.  Cumulative storage in the major upper-basin reservoirs: Cheeseman, Eleven Mile, Spinney, and Antero is at 95% of capacity.  Flow at the gaging station South Platte River near Kersey was 922 cubic feet per second (cfs), as compared to the long-term average of 684 cfs (110 years of record).  Flow at the Colorado/Nebraska state line averaged 800 cfs, as compared to the long-term average of 402 cfs (109 years of record).  December continued the very good start of the 2011-2012 Irrigation Year.  While still early in the snow season, the continued below average snow pack numbers are starting to create some concern.  The stream flows recorded by the key South Platte index gages at Kersey and Julesberg continued the well above average trend from November with kersey at 135% of its December average and Julesberg at 201% of its December average.  Storage in the basin also remained above average with end of December reservoir contents at 112% of average.  The January-March outlook for the South Platte basin is for equal chances of above or below average precipitation and temperatures.  The longer-term forecasts do show the South Platte basin shifting to warmer and drier than average conditions through the spring.

Arkansas – Flow at the gaging station Arkansas River near Portland was 468 cfs, as compared to the long-term average of 405 cfs.  Storage in Turquoise, Twin Lakes, Pueblo, and John Martin reservoirs totaled 96% of normal as of the end of December.  The Pueblo Winter Water system grand total was 50,823 acre-feet at the end of December representing a slight increase from last year’s storage to date, which was 49,143 acre-feet.  The previous five-year average for this period is 57,518 acre-feet and the average since 1990 for this period has been 62,232 acre-feet.  Conservation storage in John Martin Reservoir is about 35% below last year.  Storage since November 1st has been 7,068 acre-feet while storage a year ago for the same time period was 9,554 acre-feet.

Rio Grande – Flow at the gaging station Rio Grande near Del Norte averaged only 157 cfs (81% of normal) during December.  The Conejos River near Mogote had a mean flow of 45 cfs (86% of normal). Storage in Platoro, Rio Grande, and Santa Maria reservoirs totaled 92% of normal as of the end of December.  Alamosa received 0.27 inches of precipitation during December, 0.06 inches below normal.  Alamosa’s total precipitation of 4.60 inches during 2011 was 2.65 inches below the annual average.  For the year, the average temperature was 1.5 degrees above normal and included an all-time record warm July.  Stream flow in the basin should be below average for the next few months.  Currently, the Natural Resources Conservation Service (NRCS) forecasts the 2012 runoff to be slightly below normal for key streams in the Upper Rio Grande Basin.  Recent National Weather Service climate forecasts call for warm and dry conditions in the San Luis Valley for the remainder of the winter.  Far below average runoff was experienced in the Upper Rio Grande basin in March, April, and May 2011 as little low-elevation snowpack existed.  June was near-average for some drainages as the high snow melted out.  Thereafter, most drainages were on a sharp decline.  Stream flow in the basin was generally very poor from July through September.  There was no normal monsoonal activity during July, August, and September.  A snowstorm in early October brought desperately needed moisture to the basin.  In the end, the Rio Grande near Del Norte had annual flows of 80% of normal.  The Conejos near Mogote annual volume was 90% of normal.  The smaller drainages in the basin were not so fortunate and recorded annual runoff at 40 to 70% of normal.  In summary, 201 was a poor year for runoff.  Low precipitation during the irrigation season parched rangeland and forced reservoir releases and massive well pumping from the Valley’s aquifers.  These aquifers will already be in a stressed condition with little hope of recovery when the next irrigation season kicks into high gear.     
       
Gunnison – Flow at the gaging station Colorado River near Dotsero was 1,492 cfs, as compared to the long-term average of 1,038 cfs.  Storage in Green Mountain, Ruedi, and Williams Fork reservoirs totaled 114% of normal as of the end of December. Roaring Fork, Eagle and Colorado River flows will fall below average in January.  Blue River flows have and will continue to be slightly above average.  Mid-season snowfall has been significantly below average in the Upper Colorado Basin.  
   
Colorado – Flow at the gaging station Colorado River near Dotsero was 1,768 cfs, as compared to the long-term average of 1,310 cfs.  Storage in Green Mountain, Ruedi, and Williams Fork reservoirs totaled 105% of normal as of the end of October.  Basin wide river flows have continued a gradual decline to near average where they will likely remain through November.  Coordinated Reservoir operations to supplement endangered fish target flows in the 15-mile reach have been ended.  Green Mountain Reservoir releases have been incrementally ramped down to less than half their volume in early October.  Ongoing maintenance work continues at Shoshone Power Plant, which anticipated returning to full operation by the end of the calendar year.  Ruedi Reservoir releases will remain below 100 cfs throughout November.   Snowmaking operations began at many of the area ski resorts.  Upper Blue Reservoir will begin the seasonal 100 acre foot delivery at a rate of 5 cfs for snow making operations at Breckenridge Ski Resort on November 12th.  This is part of a Colorado Springs Utilities substitution agreement which exchanges CSU water from Wolford Mountain Reservoir.

Yampa/White – Flow at the gaging station Yampa River at Steamboat was 134 cfs, as compared to the long-term average of 107 cfs.  December October precipitation was well below average in the Yampa, White, and North Platte River basins.  The snow water equivalent (SWE) as of December 31, 2011 was 69% of average for the North Platte River basin and 69% of average for the Yampa and White River basins.  Steamboat Ski Resort is reporting a base of 27 inches and snow making is scheduled to end before the end of January.  A total of 79.5 inches of snow have fallen at the resort this season to date.

San Juan/Dolores – Flow at the Animas River at Durango averaged 202 cfs (91% of average).  The flow at the Dolores River at Dolores averaged 50 cfs (86% of average).  The La Plata River at Hesperus averaged 8.1 cfs (99% of average).  Precipitation in Durango was 0.83 inches for the month, 47% of the 30-year average of 1.77 inches.  Precipitation to date in Durango, for the water year, is 5.18 inches, 102% of the 30-year average of 5.09 inches.  The average high and low temperatures for the month of December in Durango were 41 degrees and 15 degrees.  Precipitation (0.83 inches0 was below average for the month of December in Durango.  There are 83 years out of 117 years of record where there was more precipitation than this year.