Meteorologist Reports on Unusual Weather Risks in Arizona and Southern California

Meteorological Analysis of Severe Weather Events

On interstate 10 in Phoenix on September 28, severe weather posed a risk to vehicles navigating through heavy rain. Meteorologists identified a Level 1 out of 5 risk in Arizona and Southern California, specified by the National Weather Service Storm Prediction Center. The affected areas include Phoenix, Tucson, and the immediate coastline of Southern California.

An isolated, brief tornado could appear near the Southern California coast. Rotating cells might form waterspouts that could cause brief tornado damage before dissipating inland. The weather system causing this severe risk is an upper-level low, centered offshore from Southern California. It consists of a high altitude pocket of cold air, low pressure, and spin, bringing warm, moist air northward.

Impact of Weather Systems on Arizona

Arizona will experience increased Pacific moisture, prompting a flood watch across the state. This moisture contributes to showers, storms, and potential severe thunderstorms. Wednesday afternoon could see storms depositing one to two inches of rainfall. This quick surge in rain may lead to localized flash floods due to Arizona’s sandy soil.

Beyond general storms, there exists potential for supercells. These are rotating thunderstorms spurred by the weather patterns. The upper-level low-pressure area is altering the jet stream, creating a trough that introduces wind shear. Shearing winds interact with tall thunderstorm clouds, causing rotation and some risk of tornadoes, which is uncommon in this region of the United States.