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 late-April snowstorm dumped over a foot of heavy, wet snow across parts of Colorado on Thursday into Friday, boosting snowpack for an extended ski season at local resorts.
Expanding rainfall will bring good news and bad news for people in the northeastern United States into early next week.
The risk of severe thunderstorms and flash flooding will shift to the Deep South for the first half of the weekend.
Residents of the southeastern United States may feel like the calendar has flipped ahead to Memorial Day weekend with warm and muggy weather in place for the start of May.
Those traveling during the end of the bank holiday weekend across the United Kingdom will face bouts of rain and increasingly gusty winds.
The seven-story building, which housed more than 125 single units, collapsed around 9:15 p.m. local time (2:15 p.m. Friday), officials said.
Pueblo, CO (1990)
16.8" of snow in 24 hours. This tied 24-hour record for April set from April 1-2, 1957.
Alta, UT (1991)
Record April snowfall of 136.2 inches beats the 136 inches set during 1963 and again in 1974. Season total was 580.1"; normal is 486.1".
Franklin County, PA (1994)
Gusty winds knocked a power line into a metal fence, illuminating it like the inside of a toaster. 15 cows near the fence were electrocuted.