The total combined storage in Lake Mead and Lake Powell at the end of September (the close of the “water year”) will be the lowest since 1968, when Powell was first being filled, according to the latest U.S. Bureau of Reclamation “24-Month Study” (pdf).
The current forecast calls for Lake Mead’s elevation to be 1,077.93 feet above sea level on Dec. 31, 2015, which is less than three feet above the trigger level for a shortage in 2016. That’s a little less than last month’s number. (See here for the background on how the shortage decision is made.)
Here’s the data: