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.
Tropical Depression Two has formed in the Atlantic and could become the next tropical storm of the season by midweek.
Warm and humid air in place over much of the Midwest and Northeast at midweek will contribute to the risk of drenching, gusty and locally severe thunderstorms on Wednesday.
After temperatures briefly climb to typical midsummer levels, another cooldown will roll into the Midwest and expand to the East for the last part of July.
Severe storms will fire up Tuesday afternoon and evening, threatening outdoor activities and travel for many.
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Unseasonable warmth is expected to continue from the United Kingdom through northern Europe and Scandinavia into the weekend.
Barrow, Alaska (1989)
Thunder reported for the first time since July 1982 (no rain fell with this so-called storm) July 1989 did go on to become the wettest July on record with more than 3 inches of rain.
Thompson, Manitoba (1990)
97 degrees -- record heat wave.
Bom Jesus, Brazil (1990)
About 1" of snow accumulated at elevation of 3,000; this is rare.