The latest federal forecast for runoff in the Colorado River Basin is a bit gloomier than the one of just two weeks ago. It predicts April-July runoff into Lake Powell will be 47 percent of normal, compared to 52 percent of normal that was expected in early April.
Dry weather in April accounts for much of the decline in forecasted runoff, said Brenda Alcorn, a senior hydrologist for NOAA's Colorado River Basin Forecast Center. NOAA is short for the National Oceanic and Atmospheric Administration.
"We are melting some snow right now, but in April we can still be adding to the snowpack. Through the first half of the month, that was not the case," Alcorn said, adding, "We did get a nice little storm last weekend. It did affect quite a bit of the Upper Basin, but it fell in large amounts only in a small part of the basin."
This could speed the declaration of the first-ever Central Arizona Project shortage to next year, whereas until now the most likely scenario was for the first shortage to not occur until 2017. But that won't be known until the federal Bureau of Reclamation issues more detailed reports and forecasts for reservoir water releases and the like later this year.
The latest report from the U.S. Bureau of Reclamation also offered the following statistical tidbits:
-- Snowpack in the Upper Colorado River Basin is currently only 56 percent of the median, which looks good only when compared to the 6 percent that's been recorded this spring in drought-ravaged California. The Upper Colorado figure represents a decline since early April, when snowpack exceeded 60 percent of the median.
-- Lake Mead is 39 percent full, and Lake Powell is 45 percent full.
-- The reservoir system on the Salt-Verde River complex in Arizona is 58 percent full, compared to 48 percent full on the Lower Colorado River, which also includes Lakes Mohave and Havasu, both of which are well over 90 percent full, much better than the ailing Lake Mead at Hoover Dam.
John Fleck's Inkstain blog out of Albuquerque has more detail. Read it here.