A surge of moisture from Hurricane Norbert will spread across the Southwest heading into the new week, raising the threat of flash flooding across the region.
At the same time, leftover moisture from what was once Tropical Storm Dolly will also be moving into the region, enhancing the showers and thunderstorm activity even further.
As a result, several inches of rain are possible across the interior Southwest through Monday with some storms lingering around into the middle of the week.
According to AccuWeather Senior Meteorologist Ken Clark, "Excessive rain is likely in some areas with the chance of life-threatening flash flooding."
The zone of heaviest thunderstorms will slowly expand north and west through Monday, impacting cities such as Phoenix, Tucson and Flagstaff, Arizona; Las Vegas; Palm Springs, California; and Saint George, Utah.
People in these areas should prepare for the possibility of flash flooding, especially those driving during the blinding downpours. If you are driving and come across a flooded roadway, you should avoid driving through it as the water may be deeper than it appears.
Even though the bulk of the rain will fall over the interior Southwest, enough moisture may move over Southern California to deliver a few showers and thunderstorms to cities such as Los Angeles and San Diego.
Haboobs, or dust storms, may develop ahead of some of the thunderstorms in the deserts, significantly reducing visibility and bringing traffic to a stand still.
Although the rain will bring the risk of flash flooding, it will also help battle the long term drought being experienced across the region.
Several days of showers and thunderstorms will help lessen the severity of the drought, but much more rain is required to bring an end to the drought conditions.
Unfortunately, very little rain is expected to fall in the areas that need rain the most.
"While the hardest-hit drought areas of California are not likely to receive any rain from the pattern, enough rain may fall in some locations of the Southwest to ease the drought a bit," said AccuWeahter Senior Meteorologist Alex Sosnowski.
The heavy rain expected over the Southwest through Monday may be reminiscent of 1970 when the greatest natural disaster on record for Arizona occurred.
According to AccuWeather Chief Meteorologist Elliot Abrams, "On Sept. 4, 1970, inches of rain from the remnants of Tropical Storm Norma fell in 24 hours and caused rapid flooding of multiple rivers."
Approximately two dozen lives were lost and damage was in the millions of dollars as cars and buildings were swept miles downstream during the 1970 flood.