By Reginald Stanley. Posted September 12, 2022, 10:04 PM.

Moisture from remnants of Tropical Cyclone Kay continued to bring unsettled weather to the region at the beginning of the week, mostly on Sunday.

Warmer temperatures on Sunday helped to contribute to the formation of thunderstorms across much of inland Southern California. Clusters of significant thunderstorms over the mountains began to drift westward over the inland valleys Sunday afternoon, bringing heavy rain, strong winds, thunder and lightning to western Riverside County. The Elsinore Convergence Zone saw its first major thunderstorm outbreak of the summer, with Lake Elsinore itself hit particularly hard by thunderstorms Sunday afternoon, with an additional thunderstorm hitting the city on Monday afternoon. All but two of the sixteen active WeatherCurrents stations recorded measurable rainfall during Sunday-Monday, with only Fallbrook and Simi Valley failing to receive any measurable rainfall. The rain gauge at WeatherCurrents' station in Riverside (Orangecrest) was offline during the event.

As is typical with thunderstorm outbreaks, precipitation varied widely depending on how directly a station was hit by heavy rains. Lake Elsinore recorded by far the highest amount, with a staggering 1.85 inches there over several thunderstorms on Sunday and Monday. An area stretching roughly from Temecula Valley's Wine Country - where 0.68 inches was recorded (courtesy of Jim Sappington) to most of Murrieta - was hit by particularly heavy rains Sunday afternoon. A total of 0.73 inches was recorded in Central Murrieta, followed closely by 0.68 inches at WeatherCurrents' station in northwestern Murrieta. Communities such as San Jacinto, Moreno Valley, and Temecula all experienced heavy rain but lasting a shorter time, with totals between 0.30 and 0.36 inches recorded at those locations. WeatherCurrents' stations in East Hemet and Perris, despite their relatively close proximities to stations in San Jacinto and Moreno Valley, were much drier than their neighborly counterparts. A total of 0.23 inches was recorded in East Highland (courtesy of Peter Michas). Anza recorded the lowest measurable total with 0.04 inches. Fallbrook and Simi Valley were outside of the influence of Sunday's thunderstorm outbreak.

While most of the action occurred on Sunday for most communities, some instability continued into Monday, mostly in the mountains. A thunderstorm brought additional rain to Lake Elsinore. Thunderstorm activity is expected to decrease Tuesday as the marine layer returns under troughing later in the week, with temperatures hovering around slightly-below to near-normal.

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