By Reginald Stanley. Posted March 1, 2017, 11:40 PM.

Two storms brought rain and wind to the region on the last several days of February, with the second storm being generally stronger than the first.

The first storm arrived early Sunday morning, bringing light to moderate showers well into the afternoon. Totals from that storm were generally around 1/10 of a inch in most communities. The following storm was much stronger and arrived early Monday morning, with rain continuing well into the night. Storm totals from the second storm varied widely, in stark contrast to the first storm. Foothill and mountain communities, the southern half of the Temecula Valley as well as areas east of it, and San Diego all received much higher rain totals in excess of one inch or more. San Diego's City Heights station received 3.25 inches, dwarfing all others in the WeatherCurrents network. In Temecula Valley's Wine Country, an astonishing 3.39 inches was reported by Jim Sappington. In East San Jacinto, 2.44 inches was also reported by Monty Parrott. In contrast, the Riverside-San Bernardino metropolitan area, inland communities north of Wildomar and Menifee, as well as WeatherCurrents' outlying Simi Valley station northwest of Los Angeles, all received significantly less rainfall from the storm - less than one inch. In East Highland, 0.68 inches was reported by Peter Michas. Simi Valley, northwest of Los Angeles, received the lowest total with just 0.23 inches.

Why the substantial differences in rainfall? Just after noon on Monday, the National Weather Service identified a squall line just offshore from Orange County on Doppler Radar, rapidly approaching the coastline. A squall line is a narrow band of heavy rainfall, thunderstorms, and high winds associated with a cold front. Squall lines of such strength are not very common in Southern California, but they do occur when the conditions are favorable. This produced sustained heavy rainfall in San Diego County as well as some parts of southwestern Riverside County and southern Orange County, on Monday afternoon. The squall line and associated heavy rainfall did not reach areas further north, including the Riverside-San Bernardino metro area - resulting in lower rain totals there.

The rains were heavy enough in San Diego to cause major flooding in some areas, as well as historic flows in the San Diego River. The National Weather Service reports many locations breaking daily rainfall records on February 27th. The storm was created by one of many atmospheric river events over the eastern Pacific Ocean this winter - a phenomena typically associated with El Nino events. This winter, however, is being affected by a La Nina event instead.

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