Nearly half of the United States is experiencing drought, and those conditions are likely to continue through the fall or even longer, National Oceanic and Atmospheric Administration scientists forecast Aug. 19.

Following record-breaking high temperatures in July, drought conditions spread and worsened slightly in some parts of the U.S., continuing the second dry year in a row or longer for many Western states. About 47% of the U.S. is in drought, according to NOAA experts.

While Western states are scorched by wildfires, water resources are also dwindling.

In a first, the U.S. declared a water shortage on the Colorado River, prompting water cuts, including the first shortage ever declared on Lake Mead, the country's largest reservoir, part of a larger trend.

"The water supply in the Colorado River Basin has actually been declining for about the last 20 years," Dan McEvoy, regional climatologist for NOAA's Western Regional Climate Center, said during the Aug. 19 briefing. "So this is a bigger problem than just the past two years."

Continued drought conditions contributing to lower water levels will likely lead to reduced water supplies for Arizona and Nevada beginning in 2022, McEvoy said.

Reservoirs are also critically low throughout California. Lake Oroville reached its lowest level on record and no longer had enough water to operate.

"This has forced the first-ever shutdown of the hydroelectric plant that was built there in 1967," McEvoy. "These water supply drought impacts are really starting to stack up."

The Edward C Hyatt plant and Edward C Hyatt PS pumped storage units owned by the California Department of Water Resources make up the state's second-largest hydroelectric facility, with an overall generating capacity of about 750 MW.

The drought conditions are expected to continue for the next few months at least, NOAA scientists said. NOAA's outlook for September through November calls for continued above-normal temperatures for the vast majority of the United States.

"For a lot of the Western U.S., we are expecting drought to persist," said Matt Rosencrans, meteorologist for the NOAA Climate Prediction Center. "There is some potential for drought recovery ... in the Pacific Northwest, Oregon and Washington especially west of the Cascades ... There's also some potential for improvement in southern Wisconsin and in the central parts of the Appalachians once summer temperatures go down."