By David Gale
Just as residents in Southern California start adjusting to life with lawn-watering restrictions, there are signs California’s drought may be coming to an end next winter.
Climate scientists say conditions are ripe for the formation of an El Nino over the Pacific Ocean, an intermittent weather condition that brings wet winters to the southern United States.
That means there is a good chance Southern California will get above-normal rainfall next year.
It also means that, the roofs of your apartments could cause you serious trouble if they’re not in good condition. Even if you presently have no leaks, it would be prudent to engage in some preventative maintenance if your roofs are showing their age. Even a small leak developing in the middle of a storm can, at the very least, cause a hardship for your tenants and strain the good relationships with them you presently enjoy. Naturally, no weather prediction is ironclad but all indications point to an El Nino presently forming in the Pacific which means we could be facing a very wet winter and spring.
“There are no guarantees, but we’re unlikely to have another dry winter,” said Dave Pierce, climate researcher at UC San Diego’s Scripps Institution of Oceanography.
“It generally means significant drought relief for Southern California when you have an El Nino,” said Doug LeComte, a drought expert with the National Weather Service’s Climate Prediction Center in Camp Springs, Md.
“It greatly increases the odds for heavy rains in the southern part of the state next winter,” he said. If it gets to be a monster like the one in 1997-98 that dumped more than 30 inches of rain on parts of Southern California, it would spread higher-than-normal precipitation all around the state, refilling parched reservoirs, LeComte said.
A moderate El Nino, on the other hand, might only increase precipitation in Southern California without doing anything for points north and a fledgling El Nino could do more than replenish reservoirs.
“Be careful what you wish for: You could get lots of flooding from El Nino, too,” LeComte said.
Indeed, some of Southen California’s worst floods occurred during storms spun off from various El Ninos.
Sea surface temperatures increased for the fifth consecutive month, with above-average temperatures extending across the equatorial Pacific Ocean by the end of May. Accordingly, the latest weekly sea surface temperatures indices ranged between +0.4° to +0.5°C in all four Niño regions. Subsurface oceanic heat content anomalies also continued to increase in response to a large area of above-average temperatures (+2° to +4°C) near thermocline depth. These surface and subsurface oceanic anomalies typically precede the development of El Niño.
At the start of the year, our weather was controlled by a La Nina condition that is marked by cooler-than-normal ocean water and gives us dry weather. Since then, water temperatures have risen one degree above normal. If the water continues to warm, and if prevailing easterly winds along the equator weaken in response, L’Heureux said, later this summer the climate center will declare that an El Nino has arrived.
The ocean’s temperature is important because the central Pacific is the engine for the North American jet stream. The jet is a narrow column of air six miles above the earth where winds blow extremely hard and funnel storms into areas along its path.
Strong El Ninos tend to pump moisture into the jet stream and steer it south of its normal track, across the southern tier of the United States. That tends to funnel storms right through Southern California.