Another day of hot and humid weather is expected in San Diego County on Monday, accompanied by a threat of flash flooding in the mountains and deserts because of scattered thunderstorms forecast for Monday afternoon.
"Very moist and unstable conditions will produce thunderstorms in the mountains and on desert slopes this afternoon," according to a National Weather Service advisory. "These storms are expected to produce flash flooding in some areas. "
A flash flood watch is scheduled for mountain and desert areas from 10 a.m. through Monday evening.
The weather service warned that during that time, excessive runoff from heavy downpours may cause rapid filling and overflowing of normally dry washes, creeks, small streams and low-lying areas. There is also a threat of rock and mud slides below steep terrain in the mountains and recently burned areas, according to the agency.
Desert areas also are subject to an excessive heat warning, which indicates health-threatening conditions resulting from high heat and humidity, until 10 p.m.
"High pressure to the east and monsoonal moisture will continue hot humid weather through this evening," according to an NWS advisory. "A weak trough of low pressure over the Eastern Pacific will bring minor cooling and a little less humidity for the middle park of the week."
Daytime highs in the deserts on Monday are expected to be between 108 and 118 degrees, with overnight lows of 82 to 92 degrees.
-City News Service