### Unusual Early June Rains Anticipated in Phoenix

Phoenix is on the brink of experiencing a rare early June weather phenomenon, with a storm system expected to bring significant rainfall to the area. This occurrence is particularly scarce, as recorded measurable rainfall in the first week of June has only happened 21 times since 1896, according to historical weather data. This rain would be a welcome change following a winter with below-normal precipitation levels.

A storm currently situated off the coast of Baja California in Mexico is set to move into the Southwestern United States, carrying remnants of post-tropical storm Alvin. This weather system, unusually moist for this time of year, is predicted to bring thunderstorms and brief heavy downpours to Southeast California, Southern Arizona, Southwest New Mexico, and even Phoenix from Sunday into Monday.

"For this time of year, this is quite unusual," commented Mark O'Malley, a meteorologist with the National Weather Service in Phoenix. Normally, rainfall for the first week of June is zero. However, this upcoming storm could potentially shift this norm, creating a 75 percent chance of rain at Sky Harbor International Airport by Sunday afternoon or evening, with the possibility of continuing rain into Monday.

The potential impact of this storm includes thunderstorms that could bring about half an inch of rain to areas near the airport. However, rainfall distribution could vary significantly, with some parts receiving more than others.

Peter Mullinax from the Weather Service's Weather Prediction Center highlighted the extensive reach of this storm, noting that rain and thunderstorms are likely across much of the Southwest. The affected areas include southeastern California, southern Nevada, all of Arizona, western New Mexico, the Wasatch Mountains in Utah, and parts of the Colorado Rocky Mountains.

Southern Arizona, Southwest New Mexico, and Southeast California face the highest chances of rainfall. The Weather Prediction Center has issued a marginal risk warning—level 1 out of 4—for these regions due to the potential for excessive rainfall leading to flash floods on Sunday. A portion of Southern Arizona faces a slightly higher slight risk—level 2 out of 4.

Minor flooding on roadways in the greater Phoenix area is also a possibility, as per Mr. O'Malley. While storms are not unusual in late spring, they typically don't bring rain. The monsoon season, which commences on June 15 and continues into September, is usually the period when significant rainfall is noted.

The key differentiator for this storm is the moisture being pulled in from the dissipated Alvin, emphasized Mr. O'Malley. Additionally, a strong southerly wind is aiding in drawing tropical moisture northward into the Southwest, explained Mr. Mullinax.

Alvin initially formed over the Pacific Ocean off west Mexico's coast last Thursday, bringing heavy surf to west-central Mexico and southern Baja California. Now a dissipated post-tropical cyclone, its moist remnants are set to influence weather patterns in Phoenix and the broader Southwest United States.