‘Unprecedented’ March heat wave could bring highs near 100 and last about a week

“Unprecedented.”

That’s the word that the National Weather Service is using to describe the upcoming heat wave, which could bring near-triple-digit temperatures to the coastal areas of Southern California over the next week.

Temperatures could be high enough to make this the hottest March on record, even though we’re only 10 days into the month.

This week’s heat

As high pressure builds over the area, the first peak of the heat wave is expected to arrive on Thursday and Friday, with temperatures 30 degrees above normal in some spots. The coastal valleys (San Gabriel and San Fernando) could see temperatures in the upper 90s to 100s, while those along the coast will have to sweat through temperatures in the low to mid-90s. Desert areas will be slightly cooler, with temperatures in the upper 80s. Santa Ana winds are also likely, boosting temperatures and drying things out to a more severe degree.

Next week's heat

While we’ll get a slight reprieve over the weekend, the heat is expected to ramp back up to similarly extreme levels next week, though the exact days are unclear as it’s still a bit far out. There are some signs that the heat could break by the end of the next week, but that’s not certain.

“It’s hard to place into words how rare this will be,” said Robbie Munroe, meteorologist for the National Weather Service in Oxnard. The NWS will likely issue some sort of heat advisory due to the health risk the weather poses. “Normally we don’t have to communicate this type of messaging in March."

How does this effect the water supply?

Snowpack in the Northern Sierra — where California gets a substantial amount of water — is at just 34% of normal for early March. The Colorado River Basin is at 67% of normal. While California’s reservoirs are in good standing, it could be a rough year ahead for water. Much of the West is currently experiencing drought conditions.

What kind of fire risk is there?

There should be enough soil moisture left from earlier rains to prevent any fast moving fires from breaking out during this wave, though quick-drying grasses could be a risk.