By Reginald Stanley. Posted March 20, 2024, 1:48 AM.

A persistent cutoff low over the southwestern United States brought scattered showers, gusty winds and scattered thunderstorms intermittently between March 14th and March 19th.

Thunderstorms were the main event over the course of the cutoff low's passage through the region, with most communities recording their greatest one-day rain totals from the storm on March 15th alone. WeatherCurrents stations in Anza and Fallbrook were hardest hit, with Anza being struck by multiple thunderstorms throughout the day; Fallbrook was hit by a late-afternoon thunderstorm. These thunderstorms followed a period of very gusty Santa Ana Winds that had battered the region on March 14th. More sporadic, spotty light rain activity had also affected parts of the region on March 16-17, however totals were very light or not measurable at all. The region experienced a significant convective outbreak around mid-day on March 18th as another shortwave from our cutoff low had reignited over the region's transverse mountain ranges and convergence zones. Much of Southern California west of the mountains experienced intense thunder and lightning on March 18th as widespread convection developed. Lake Elsinore received the most rain on March 18 where 0.30 inches fell during a thunderstorm. These thunderstorms largely missed or narrowly hit most WeatherCurrents stations, resulting in relatively low precipitation totals for the date.

Storm totals for the period lasting from March 14-19 varied considerably, due to the convective and showery nature of the storm system. Anza recorded the highest total with 0.89 inches through March 18, when it was presumably knocked offline during thunderstorms. South Fallbrook followed with 0.51 inches, and Lake Elsinore where 0.44 inches fell. In East Hemet, 0.23 inches was recorded, while neighboring San Jacinto received only 0.04 inches. In Temecula Valley's Wine Country, 0.14 inches was reported through March 19 (courtesy of Jim Sappington). On the drier end of storm totals, Simi Valley was the only WeatherCurrents station to not receive any measurable rainfall during the whole period ending March 19 - likely owing to its northwesterly location, further away from the influence of the cutoff low. Residual moisture was confined to the mountains on March 19, and had departed the region by Tuesday night as a deeper marine layer formed. High pressure is forecast to keep the region warmer and drier through Friday, before more potential wet weather next weekend.

Here are the rain totals for the WeatherCurrents network and associates:

1. Anza storm total through afternoon of March 18.
2. French Valley season total incomplete.