The anomalous summer rains came to California thanks to Hurricane Dolores, which surged to a powerful category 4 last week. Since then, the remnant storm has tracked north parallel to to the coast, pumping tropical moisture into the Southwest U.S.
On Saturday, 1.03 inches of rain fell in San Diego, setting a new record for wettest day in July and pushing the month to the wettest July on record. An additional 0.66 inches fell Sunday, and as of Monday morning, the monthly rainfall total was an incredible 1.7 inches. The previous wettest July on record was in 1902, when 0.92 inches of rain fell. Los Angeles set a new record for wettest July, too, after 0.38 inches fell over the weekend.
These rainfall totals might not seem like much — all of San Diego’s rainfall so far this month could fall in any number of garden-variety thunderstorms east of the Rockies today — but for Southern California, this is epic summer rain. Mashable’s Andrew Freedman pointed out that San Diego’s weekend rains were more than what they saw in all of January this year. January is typically San Diego’s second-wettest month in the year, with winter being the rainy season and summer being the dry season.
As National Weather Service meteorologist Joe Sirard said, “Really, this is super historic.”
However, even when California gets epic, super historic, rarely-seen rainfall, it’s not enough to to bring any kind of drought relief to a region that is quite literally running out of water. It won’t even come close.
That’s because, four years into the worst drought the state has ever seen, the rainfall deficit in California is ginormous, and the weekend rain fell over a relatively small region of the state.
NOAA estimates that to bust the drought in six months, 12 to 16 inches of rain would need to fall in California’s Central Valley — the epicenter of the state’s agriculture industry, as well as many of its critical reservoirs. According to NOAA, that is the amount of water needed to bring things back to normal after taking into account the moisture recharge of the soil, runoff and water usage. Even to simply alleviate the drought conditions, to just make it better in the Central Valley in the next six months, nine to 12 inches of rain would need to fall.
So what are the chances that this much rain or snow will fall in California by early next year? NOAA places the chance of the drought ending in the southern Central Valley at anywhere from zero to 9 percent. The forecast is slightly wetter in the northern half of the state, where there’s about a 34 to 43 percent chance that enough rain will fall in the next six months to end the drought there.
The better odds for Northern California are bolstered by the ever-strengthening El Nino in the tropical Pacific, which appears to be on its way to one of the strongest on record. If all of the atmospheric puzzle pieces come together, this year’s El Nino could help California work its way out of the drought — or at least get into a better, wetter position — by providing much-needed wintertime rain and snow.
All this being said, what California really needs is a few years of average rainfall. Not epic or historic, or even above average. Just a few “normal” years could be enough to put the state back on track. But California hasn’t seen a year close to normal since 2011.