April 24, 2013

Current Snowpack

Several potent spring storms since April 8 have given the snowpacks a significant late boost in Wyoming, northern and central Utah, and northern and central Colorado, with many SNOTEL sites accumulating 2-6" of SWE over the two-week period. The Current Basin Snowpack map from NRCS shows many basins across the region now having 90–110% of median snowpack for April 23. While these values this late in the season can be misleading—the median snowpack curve has peaked and is declining at most sites after mid-April—the "current SWE as % of peak" values, especially at the highest-elevation sites, suggest that most of this recent increase in % of median is "real" and will be reflected in greater runoff than was forecasted on April 1.

The recent storms did not benefit southern Colorado and southern Utah nearly as much as farther north, and these basins remain at well below median snowpack.

Seasonal Climate and Drought Forecasts

The latest monthly and seasonal Climate Outlooks released on April 18 by NOAA CPC show no tilt for precipitation for May, but a tilt towards drier-than-average conditions for the May–July period for all of the region, with the strongest tilt over western Colorado and eastern Utah. For the June–August period. the area with dry tilt shrinks and shifts to southeastern Colorado. The CPC Climate Outlooks once again show enhanced odds for above-normal temperatures for the upcoming seasons, consistent with the long-term warming trend. The latest CPC Seasonal Drought Outlook released April 18 projects that over most of our region drought conditions will persist, but some improvement is expected in far eastern Wyoming and the eastern half of Colorado over the next three months.