The risk of localized flash flooding continues through the end of the week over part of the interior West.
Cities at risk for flash flooding during the random storms include Las Vegas, Phoenix, Tucson, Flagstaff, Albuquerque, Salt Lake City, Cedar City in Utah and Riverside, Calif.
According to Western Weather Expert Ken Clark, "An upper-level disturbance drifting in from the Pacific will focus an already in place flow of tropical moisture, known locally as the monsoon."
The end result will be more numerous and locally, extra-drenching showers and thunderstorms from interior California to New Mexico, northward to Utah and Colorado.
The storms will tend to favor, but not be limited to the high ground.
Isolated downpours can quickly flow downhill, causing canyons and arroyos to quickly fill with water.
The spotty downpours can also lead to debris flows in recent burn areas.
While area residents will welcome any non-destructive rainfall, a number of the storms will bring little or no rainfall, frequent lightning strikes and the risk for new wildfires.
"By the end of the week the storms will consolidate farther to the east and south over the Four Corners states as drier air invades from the north and west and the disturbance pushes inland," Clark added.
At such time the risk for flash flooding in Las Vegas and Phoenix will have ended.
Meanwhile, a stalled front will continue to bring rounds of drenching thunderstorms and the risk of flash and urban flooding to parts of the southeastern U.S. this week.
A renewed risk of severe weather will threaten portions of the north-central United States into midweek.
Heavy downpours will raise the concern for flash flooding along the Gulf Coast and lower Mississippi Valley through midweek.
A stifling heat wave will remain entrenched across the Northeast this week, despite a brief reprieve in humidity for some.
Dangerous heat will surge northward and send temperatures rising across the northwestern United States this week.
Severe thunderstorms rumbled through the Northeast on Monday, lashing the region with damaging winds while also unleashing heavy downpours that triggered flash flooding.
Here are five easy ways to stay cool in sweltering summer heat.
Houston, TX (1978)
For the second straight day, a lightning bolt struck an oil storage tank. This strike caused a 5 alarm fire.
Hamshire, TX (1989)
A total of 4.46" of rain in two hours (near Port Arthur).
Newark, NJ (1989)
99 degrees -- tied 1940 record.