When Californians suffer under oppressive heat, as they have for weeks, another concern is sure to follow: drought.
Long-term weather outlooks for the Golden State do not provide much reassurance. While the stubborn heat gripping the state is expected to ease starting Wednesday, there is zero rain in the forecast.
Indeed, drought conditions have worsened across California compared with one year ago, and are expected to get more severe through December. Sixty-nine percent of California is considered to be in moderate drought conditions or worse, according to the National Drought Mitigation Center. One year ago, none of the state was in that condition.
The national drought center bases its outlook largely on soil moisture measurements.
California officials look at drought a little differently, basing it on whether people's water needs are being met. The state Department of Water Resources is a long way from declaring a drought, saying it depends much more on local conditions and regional demand.
But it acknowledges the potential is there.
For instance, most of the state's major reservoirs are at below-average storage levels. California avoided drought this summer because those reservoirs were filled to the brim by a wet winter in the early months of 2011. Such was not the case January through March of this year, and the surplus is gone.
Examples include Folsom Lake on the American River, which stood less than half full Monday, with capacity about 81 percent of average for this time of year.
"Groundwater levels are starting to go down a little in some places, and reservoir storage levels are starting to go down," said Jeanine Jones, interstate resources manager at the DWR. "If this winter is dry, we'll feel it more."
On Sunday, Sacramento set a record with 26 days in September at 90 degrees or hotter, according to the National Weather Service. That broke the previous record of 24 days set in 1974.
Fresno also broke records for the hottest average temperatures in August and September. The prior records had stood since 1931 and 1984, respectively.
The first few days of October offer little relief. The high temperature in downtown Sacramento on Monday was 100 degrees, one degree shy of the record. Today's peak is expected to reach 99 degrees.
"We're going to break some records today," said Bill Patzert, a climatologist at the NASA Jet Propulsion Laboratory in Pasadena, where today's predicted high is 102. "I tried to figure out whether this is some sort of precursor for the winter. Maybe I'm getting senile, but I don't see it yet."
The rest of the week will bring a gradual cool-down, to the point that weekend temperatures may actually be in the low 80s below normal and cloudy. That means the massive dome of persistent high pressure over California's coastline, the culprit behind the hot trend, is finally breaking down.
Still, despite the promise of clouds, there is no rain in the forecast. As a result, fire hazards have worsened across Northern California.
Conditions have been so dry and hot that, on Monday, the National Interagency Fire Center extended an "above average" fire warning across Northern California all the way to the edge of the Pacific Ocean. It also warned that warm, dry winds could blow across the state from inland deserts next week, rather than from the ocean as usual.
The National Weather Service has declared a weak El Niño to be in play this winter. That means the tropical Pacific Ocean is warmer than normal, a cycle that typically alters climate patterns to produce dry conditions in Northern California and wet conditions in the south part of the state.
In a long-range forecast issued Sept. 20, the weather service said odds favor just that: dry weather through December in Northern California, which happens to be where most of the state's water supply is stored.
But Patzert disagrees with that forecast, and said El Niño conditions are ending. That will result in "neutral" conditions, which he also calls "La Nada." And it means precipitation effects will be even harder to predict, he said.
"This is when you gotta be way smarter than me, or just flat lucky, if you are forecasting snowpack and rainfall for California," he said.
The situation is not preoccupying water managers in the state, said Tim Quinn, executive director of the Association of California Water Agencies. They are accustomed to uncertainty, especially this early in the season.
"I'm not hearing a lot of dread at the present time," Quinn said. "I never paid a lot of attention to the long-term prognosticators. They're wrong as often as they are right. And no matter what they say, you want to be prepared for the worst."