By Reginald Stanley. Posted August 22, 2023, 1:47 AM.

Hurricane Hilary, downgraded to Tropical Storm intensity as it reached Southern California, brought significant rain and wind to the region, and produced areas of flooding, especially in the deserts. As Hilary made landfall in northern Baja California, the tropical cyclone picked up speed significantly and also took a more easterly track, which lowered rain amounts in some areas. Anticipated convection largely failed to materialize west of the mountains, limiting thunderstorm development. However, numerous floods did occur and a tornado warning was briefly issued for the mountain communities of Alpine and Descanso in southern San Diego County, for 22 minutes on Sunday afternoon. Palm Springs was significantly affected by severe flooding Sunday.

Rain amounts from Hilary were particularly high in the mountains and deserts. At WeatherCurrents' station in Pinon Hills, an incredible total of 6.63 inches was recorded on Sunday alone - the highest one-day total ever observed at any WeatherCurrents station. To the east, Anza recorded 3.62 inches up through approximately 4:34 PM Sunday - until the station was knocked offline, likely due to a weather-related power outage. Anza's true total likely exceeded four inches. Simi Valley was particularly hit by heavy rains Sunday with 3.68 inches recorded there. Temecula and Murrieta both also received totals exceeding three inches. A large portion of remaining WeatherCurrents stations received between two and three inches of rain, being near or slightly below initial projected totals for those areas. In Temecula Valley's Wine Country, a total of 2.52 inches was reported (courtesy of Jim Sappington). Hemet and San Jacinto were considerably drier, being the only two active WeatherCurrents stations to receive under two inches of rain from Hilary. WeatherCurrents' station in Riverside (Orangecrest) reported a suspiciously low total of 1.10 inches, believed to be erroneous as this total is inconsistent with storm totals from nearby areas. Orangecrest's total should be closer to two inches, according to data borrowed from Wunderground stations located in Orangecrest's immediate vicinity.

Tropical Cyclone Hilary moved north from Southern California into southern Nevada on Monday, losing all of its tropical characteristics and becoming a post-tropical cyclone, or remnant low. Warm, dry conditions are forecast to remain in place throughout the region this week until a surge of monsoonal moisture brings thunderstorm chances to the mountains and deserts on Thursday.

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

1. Anza storm total incomplete due to likely power outage during storm.