By Brian Thompson
An early-season storm system moving across Great Basin of the United States will help to trigger numerous thunderstorms and with localized severe weather and the risk of flash flooding through the weekend.
The greatest risk of flooding and severe storms will extend into Saturday evening.
A small number of the storms will be severe, but can bring wind gusts to 65 mph, frequent lightning strikes and a short-lived tornado. The storms have the potential to not only cause property damage and power outages, but can bring sudden low visibility from blowing dust.
While rainfall amounts will vary greatly because of the scattered nature of the moisture, the potential will exist for more than 2 inches of rain. This amount of rain is more than what typically falls during the entire month of September in many parts of Arizona and Utah.
The threat for flash flooding will include Phoenix, Las Vegas and Salt Lake City.
Motorists traveling on interstates 10, 15, 17 and 40 through Arizona and Utah, should be prepared for blinding downpours and flooding. Remember that many vehicles can be carried away by only a foot or so of water.
Despite the threat for flash flooding, the rain will beneficial to portions of the interior West and Southwest that have been dealing with drought.
This map, which focuses on the Southwest is a culmination of the U.S. Drought Monitor, the Palmer Drought Index and soil moisture departure from average as of Thursday, Sept. 25, 2014.
While this system will not help bring much, if any, rainfall to the hardest-hit drought areas in California, some places farther east will receive welcomed rainfall. Parts of southern Utah and northern Arizona are battling a long-term severe drought and will benefit from the rain.
The overall weather pattern that is beginning to spawn this storm has already helped bring much-needed rainfall to portions of northern California. The rain helped firefighters battling large wildfires in that area.
As isolated severe storms and flash flooding focus over the Great Basin, colder air will spill into the Sierra Nevada.
According to Western Weather Expert Ken Clark, “Snow will fall mainly above 7,500 feet in the Sierra Nevada this weekend with 4-8 inches over the high country.”
On Sunday, a few showers and thunderstorms will continue as the storm moves off to the east and loses intensity.
Drier weather will prevail across the Four Corners by Monday and Tuesday.
AccuWeather Senior Meteorologist Alex Sosnowski contributed content to this story.