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A dome of high pressure over New Mexico is preventing Southern California from getting the cool sea breeze that keeps temperatures pleasant. Heat warnings and hot temperatures are expected to continue this week. Fritz Coleman reports for the NBC4 News at 5 p.m. on August 13, 2012.
Flash flood watches were issued Monday afternoon for Riverside and San Bernardino counties as more severe weather threatened the region.
The watches, in effect until about 9 p.m., come after strong winds snapped power poles and damaged roofs Sunday in Riverside County.
Earlier Monday, a flash flood warning -- a more urgent advisory -- was in effect through 4:30 p.m. for the two counties. The National Weather Service issues flash flood warnings to inform the public and public safety agencies that flash flooding -- rapid and extreme flow of water into a normally dry area -- is in progress, imminent or highly likely.
A flash flood watch means conditions may develop that lead to flash flooding.
Warnings often are preceeded by a flash flood watch, which indicates conditions that are favorable for flash flooding.
Late Sunday, a storm system moved through the region during the evening and prompted a flash flood watch. A tornado warning was issued Sunday after weather spotters reported funnel clouds.
Damaging winds, possibly a tornado, were reported west of Perris near Route 74 and in the Nuevo area, just east of the 215 Freeway.
"She said it sounded like the house was coming apart," said a Nuevo resident who received a call from his daughter. "The sky got real dark, lightning was flashing like crazy.
"This is Oklahoma weather."
The National Weather Service is attempting to determine whether the damage in Nuevo was caused by a tornado.
More storms are possible Monday.
The severe weather warnings come amid a heat wave that has blanketed Southern California and prompted another Flex Alert, a call from the state's main power grid operator to conserve energy.