The sun is shining today in Los Angeles after an unusually wet few months—but don’t let the verdant hills and blue skies fool you. The area is not drying out. Back-to-back storms are headed to Southern California, and the second will be the strongest so far this season, National Weather Service meteorologist Tom Fisher tells Curbed.
Earlier this week, forecasters were hesitant to say for sure just how potent these storms would be, but now the Weather Service is describing them as “dangerous.” Fisher said he’s 100 percent confident they’re going to be a big deal. Not only will they dump a lot of rain on the area—rainfall rates are expected to reach a rate of 1 inch per hour—they’ll move through the area slowly and unleash gusty winds.
As with another big storm that hit the region earlier this winter, these will be the result of a weather system known as an “atmospheric river,” which moves high concentrations of water vapor from the tropical Pacific and blasts it at the West Coast, like a fire hose.
Here are five other things to know about these storms, which the Weather Service advises should be taken “very seriously.”
1. When will the storms arrive?
Fisher said to expect rain to arrive late Thursday night into early Friday. Precipitation will be light at first. But drizzle will turn to full-on showers, if not downpours. There will likely be a 12-hour period of rainfall, and half of that will be “intense,” he said.
The peak of the heavy rain is expected early Friday morning through Friday night into early Saturday morning. It will taper off Saturday, but scattered showers could linger through the evening.
2. How much rain are we going to get?
In the low-lying areas in and around Downtown Los Angeles, expect 2 to 4 inches of rain. The foothills and mountains could see double those amount, and the Weather Service said 8 inches might even be a conservative estimate for south-facing slopes of the foothills and mountains.
— NWS Los Angeles (@NWSLosAngeles) February 15, 2017
3. How much rain has already fallen?
City News Service reports that Downtown has recorded a whopping 16.25 inches so far this season, which runs from October to April. That’s almost double the normal amount of 8.96 inches.
4. What about snow?
Since the atmospheric river will tap into warmer water vapor, snow levels will remain relatively high at above 8,000 through Friday evening before lower to around 6,000 to 6,500 feet.
5. Will there be flooding?
Most likely. A flash flood watch is in effect from Friday morning through Saturday morning. “The potential for widespread flooding and flash flooding is a definite threat. Not just for the recent burn areas, but anywhere there is the potential for flooding,” says the Weather Service.
— LA EMD (@ReadyLA) February 15, 2017