Rachel brings a variety of weekend weather to southern Arizona which includes wind, rain and cooler air

Tucson residents can expect a sharp change in the weather this weekend as moisture and wind from Tropical Storm Rachel move into southern Arizona. The storm’s remnants are expected to bring gusty conditions, isolated thunderstorms, scattered showers and a noticeable cooldown. The most active period is forecast from Saturday afternoon through Sunday afternoon, with another chance of rain Monday into Tuesday as a cold front crosses the region.

A Wind Advisory is in effect for much of southern Arizona, including Tucson, from 2 a.m. Sunday through 11 p.m. Sunday. Wind gusts could reach 55 mph in parts of central and western Pima County from Sunday morning into the afternoon. The strongest winds are expected west of Tucson, but gusty conditions may affect travel, outdoor activities and areas vulnerable to blowing dust. The broader storm system could also produce isolated severe thunderstorms, particularly Saturday afternoon.

Temperatures will begin the weekend unusually warm for the approaching change. Forecast highs are in the upper 80s to lower 90s Saturday, before falling into the upper 70s by Tuesday. The rain itself is expected to be limited in most of southern Arizona, with totals generally ranging from a trace to one quarter of an inch. Some locations could receive somewhat higher amounts, especially where thunderstorms develop. A second round of showers may arrive Monday or Tuesday as cooler air moves in from the northwest.

Rachel is expected to pass west of Tucson on Sunday after moving toward the northern Baja Peninsula. Its moisture and upper level circulation will spread inland even as the storm weakens over land. The system is forecast to hold onto tropical storm status until making landfall in northern Baja on Saturday night, with the remnants possibly reaching southeastern California early Sunday. Forecasters say the combination of warm ocean water and support from an approaching jet stream could allow Rachel to strengthen somewhat before landfall.

The storm has already prompted an unusual tropical storm watch for parts of Southern California, including San Diego County and San Clemente Island. A watch means tropical storm force winds, mainly in gusts, are possible within 48 hours. Northern Baja is under tropical storm warnings, where winds near 40 mph are considered more likely. Rachel is the first storm to trigger a tropical storm watch anywhere in Southern California since the remnants of Hurricane Hilary affected the state in 2023, according to the National Weather Service history cited in the reporting.

Southern California is also coming out of a record setting early October heat wave. Downtown Los Angeles reached at least 100 degrees for five straight days, while San Diego recorded two consecutive days above 100 degrees. Several cities across California and the interior West recorded their warmest start to October. Rachel and the incoming cold front are expected to end that heat, with temperatures across parts of the Southwest dropping into the 70s and 80s by Monday. Tucson’s forecast cooldown is part of that larger regional shift.

The storm’s effects could be much more serious in areas closer to its path. Rachel may bring strong winds, flash flooding and coastal flooding to Southern California, Baja California and the lower deserts. Forecast concerns include flooding in normally dry washes, arroyos, canyons and urban areas, along with blowing dust, tree damage and power outages. Southern California beaches could see dangerous surf, rip currents, erosion and flooding through early next week. Some forecasts call for one to five inches of rain across broader parts of the region, with locally higher amounts, although southern Arizona rainfall totals are expected to be considerably lower.

The unusual behavior of Rachel is tied in part to exceptionally warm eastern Pacific waters. Ocean temperatures near the storm are reported to be 10 to 13 degrees above average, giving the system additional energy despite dry air and limited thunderstorm activity near its center. Forecast models show a range of possible outcomes for Southern California, from a moderate storm impact south of Tijuana to a direct tropical storm strike in San Diego County. Higher elevations are considered more likely to experience damaging winds than lower elevations.

Rachel is not the only major weather threat in the region. Major Hurricane Simon is forecast to reach Mexico’s Jalisco state Sunday at Category 4 strength, bringing potentially catastrophic winds, storm surge and flooding rain near the west central coast. Up to 30 inches of rain could fall in parts of southwest Mexico, creating a serious landslide risk. Simon’s remnants may later contribute moisture to the central United States. For Tucson, the immediate concern remains Rachel’s wind and rain, followed by the cooler conditions expected early next week. Weather is forecast to settle into a more typical fall pattern by the end of next week.