Moisture from tropical systems Dolly and Norbert will bring drenching rain to part of the drought-stricken Southwest starting at the end of the week.
Enough rain may fall in some locations to ease the drought a bit, and too much rain may fall in other areas to the point that flash flooding, mudslides and road washouts occur.
In addition to northwestern Mexico, the bulk of the rain will be centered on Arizona and western New Mexico, but some rain will reach southern Nevada, southern Utah, southwestern Colorado and part of Southern California.
According to AccuWeather Senior Meteorologist Ken Clark, "Excessive rain is likely in some areas with the chance of life-threatening flash flooding."
This is due to the rocky terrain, steep hillsides and arroyos. Runoff is often very rapid and can fill the typically dry stream beds.
Early September marks the anniversary of the greatest natural disaster on record for Arizona.
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 cause 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.
People are urged to be vigilant during the pattern as the weather, stream and roadway conditions can change in a matter of minutes, depending on where showers and storms tend to cluster.
A general 1 to 3 inches of rain is forecast this weekend, centered on Arizona. However, much higher amounts are possible at the local level.
Some locations, such as Las Vegas and Phoenix, have the potential to double their rainfall for the year so far, which could bring their rainfall for the year back to normal. Additional rain may fall during the first part of next week.
Since the drought is much more severe in much of California, it will take more than a couple of rounds of spotty showers and thunderstorms to make a difference where it does rain in the state.
"The current California drought is one of the worst two or three since the 1870s, and in some areas it is the worst in recorded history," Clark said.
Over the past several years, the state has only received approximately 50 percent of normal rainfall. The drought has become even more severe this year due to to little snow over the mountains over the winter and very little rain since.
Norbert is forecast to weaken during the weekend. The circulation around the distant storm will hold the key as to how much, if any, moisture is directed toward the coast of Southern California.
"At the very least, people in coastal Southern California can expect more clouds and an increase in humidity this weekend." Clark said.
"Showers are not out of the question for Los Angeles, San Diego and other coastal areas."
In addition to the chance of some rain in Southern California, Norbert will send waves toward the beaches this weekend.
While the surf will not be as intense as that from Marie, it will bring the risk of strong rip currents.
"if you are not a strong swimmer or an experienced surfer, it will be best to stay out of the water," Clark said.