LOS ANGELES – California may be out of the drought, but uncertainties remain around the state’s water supply, according to a report from the state’s water agency.
The state experienced the highest level of rainfall this year since 1983 – making the year the wettest in terms of runoff, according to the California Department of Water Resources.
But the dramatic swing in water conditions highlights the need to develop better long-range weather forecasting to cope with the state’s highly variable annual rainfall, DWR said.
DWR said it wants to narrow the forecasting gap with improved sub-seasonal to seasonal forecasting. Working with researchers at the National Aeronautics and Space Administration and the Scripps Institution of Oceanography, DWR said it is is developing innovative technology to forecast land-falling atmospheric rivers.
“Current short-term forecasting for seven days out is 70% accurate, while the 14-day forecast is only 7% accurate,” said DWR Director Grant Davis. “That isn’t adequate for water management. Advancing accurate, even longer-range forecasting is critical for our ability to plan for California’s highly variable weather.”
Despite record-breaking rainfall in northern California in water year 2017, drought impacts still linger.
California Gov. Jerry Brown issued an executive order in April to end the statewide drought emergency, but maintained a state of emergency for the counties of Fresno, Kings, Tulare and Tuolumne, where homes with dry or contaminated private wells continue to receive emergency drinking water deliveries.
The record-setting precipitation in northern California and above-average rainfall elsewhere contributed to flooding in several river systems.
Fifty-two of California's 58 counties declared states of emergency due to the January storm sequence, and flood fight materials and specialists were pre-positioned in Merced, Butte, Stanislaus, Fresno and San Joaquin counties based on the forecasts in anticipation that local agencies would request support.