The extended California drought continues to worsen, with a third of the state now under exceptional drought conditions.
About 25 percent of the state had been gripped by the highest level of drought for the last two months, but the most recent U.S. Drought Monitor report shows that the exceptional drought conditions expanded in coverage to 33 percent.
Drought conditions also expanded in Arizona and Nevada, the Drought Monitor showed.
Spotty afternoon thunderstorms will occur in California and Nevada from mid-July through mid-August as the monsoonal rains arrive in the Southwest, said AccuWeather.com Senior Meteorologist Jack Boston, a member of the Long-Range Forecast Team.
"This is the kind of activity that doesn't help the drought," he said. "Even though it's so dry, they still could get flash flooding from one of these gully-washers, but it doesn't solve the drought."
The U.S. Environmental Protection Agency warns of water woes in the Southwest as warming decreased spring snowpack and Colorado River flows, both important water sources.
"Future warming is projected to produce more severe droughts in the region, with further reductions in water supplies," the EPA said on its Climate Change website. "Future water scarcity will be compounded by the region's rapid population growth, which is the highest in the nation."
It continues to put stress on agriculture, recreation and water supplies in the Southwest.
Severe water restrictions continue in Williams, Arizona, northwest of Flagstaff, where the city has faced a critically low reservoir level since February after an extremely dry winter.
Williams has received only 2.39 inches of precipitation since Jan. 1.
Additional Arizona cities may be forced to impose water restrictions if the drought continues. The New York Times reported on June 17 that Arizona could run out of water in six years.
Pamela Pickard, president of the Central Arizona Project's board, wrote on June 19 in the water agency's blog that two scenarios exist if the Colorado River basin continues in drought for another 10 years.
The scenarios are water conservation measures and reduced usage in the basin states or federal intervention with decades of lawsuits, Pickard said.
Well-above-normal temperatures are fueling the drought's grip in California.
At the end of May in California, the Sierra snowpack's water equivalent was almost zero, the state said. California residents have been asked to voluntarily cut back water usage by 20 percent.
In Nevada's Las Vegas Valley Water District, Lake Mead is more than 3 trillion gallons below capacity, a situation that only after many years of above-average runoff will be corrected.
Conservation measures by area residents have helped, the district said. Southern Nevada has reduced its daily demand from 314 gallons per person a day in 2002 to 222 gallons per person a day in 2011.
There is some hope to lessen the drought later this year as El Niño becomes a presence in the United States, Boston said.
"Later in the fall and winter, they may get enough rain to make a huge difference," he said.
While beneficial rains haven't fallen in most of the Southwest, some areas of the Plains have recovered because of recent rounds of rain and thunderstorms.
Exceptional drought conditions improved in Oklahoma and Texas for mid-June.
Only 6.5 percent of Texas was in the most serious drought, down from 25 percent at the end of May. Oklahoma fell from 34 percent from the week of May 20 to almost 15 percent for the week of June 17.
The extreme drought in Kansas has also lessened.
The percentage of the state in extreme drought - the second highest level - had fallen from 47 percent from the week of June 3 to 21 percent by the week of June 17, the Drought Monitor reported.