By Reginald Stanley. Posted April 11, 2020, 2:18 AM.

A slow-moving, moisture-laden cutoff low brought rain and mountain snow to the region for over five consecutive days, becoming the wettest storm system to affect Southern California in April in more than two decades.

The storm dragged out starting late on the evening of April 5, alternating between light, moderate and sometimes heavy rain over the course of the week across the region, depending on where the cutoff low and associated moisture was concentrated during each day. A significantly large portion of the western United States was affected by the cutoff low, including the states of California, Nevada, Utah, and northwestern Arizona. The days when the largest rain totals occurred were April 6 and April 10, however some WeatherCurrents stations recorded high rain totals on other days. The convection expected on several days during the storm generally failed to materialize, however bursts of heavy rainfall did occur across some parts of the Inland Empire.

Storm totals for April 6, one of the wettest days of the week, ranged from 0.63 inches in Hemet to 1.96 inches in De Luz, across the WeatherCurrents network. In East Highland, a total of 2.81 inches was reported on April 6 alone (courtesy of Peter Michas), as well as a total of 1.56 inches in Yucaipa (courtesy of Don Kramer). In Temecula Valley's Wine Country, a daily total of 1.81 inches was reported (courtesy of Jim Sappington). Most WeatherCurrents stations recorded a total exceeding 1 inch on April 6, with Simi Valley falling just under with 0.94 inches. Hemet made up for its relatively low April 6 total the following day, recording 1.97 inches on April 7 - higher than any other WeatherCurrents station for that day. April 8 and 9 were not generally as wet, as Southern California remained in the drier part of the cutoff low during those two days. Precipitation picked up significantly on Thursday evening, with heavier rain moving into the Temecula Valley and Simi Valley continuing overnight and becoming more widespread.

April 10 saw some of the most widespread, heavy rainfall since April 6 across most of the region. South Temecula, De Luz and Fallbrook all benefited from particularly heavy rainfall on Friday, with all three exceeding 2 inches of precipitation on April 10 alone. The Temecula Valley, Hemet, De Luz and Fallbrook received high rain totals on Friday, while other parts of the eastern valleys, Riverside, and the more northerly locations including Simi Valley and Pinon Hills were somewhat drier. The National Weather Service had issued a Flash Flood Warning for southwestern Riverside County and part of northern San Diego County through Friday evening, due to unexpectedly intense wrap-around moisture affecting the area. Six-day storm totals ranged from just under 3 inches in Simi Valley, to over 6 inches in East Highland. The majority of storm totals accumulated up to between 3 and 6 inches across the WeatherCurrents network, as of 12 AM Saturday. Six-day storm totals in East Highland were 6.31 inches (courtesy of Peter Michas) as well as 5.62 inches in Yucaipa (courtesy of Don Kramer). A total of 5.29 inches was reported in Temecula Valley's Wine Country (courtesy of Jim Sappington). In Orange County, a six-day total of 2.80 inches was reported in the city of Orange (courtesy of Dan). The path of the cutoff low passed over Southern California yet again Friday afternoon, finally moving to the east by Friday night, however sporadic light rain was still falling in parts of the region early Saturday morning.

WeatherCurrents' stations in Perris and Moreno Valley experienced rain gauge problems. Perris storm totals have been recalculated and will be corrected. Moreno Valley experienced a rain gauge outage on April 10, as well as Anza on April 6.

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