West LA Times

UCLA climate scientist Daniel Swain will host a video session today to provide context on the ongoing major heatwave affecting the West Coast. The session, scheduled for 2 p.m. PT, follows Swain's Monday blog post where he detailed the unusual nature of the current weather conditions.

Swain noted that while September heatwaves are common in the region, this particular event is expected to break daily heat records and become the most significant of the year in coastal Southern California, with temperatures reaching up to 115 degrees Fahrenheit.

“June and July were so persistently and extremely hot across most of California that the summer will likely officially end up as the hottest on record despite an August that featured near to even below average temperatures in many areas. That is genuinely remarkable,” Swain wrote.

He highlighted that although much of California’s immediate coastline avoided record-breaking heat this season, other parts of the state experienced a record-hot summer. “Most of California’s immediate coastline missed out on record heat this season (including some of the most densely populated portions of the SoCal megalopolis) — meaning that while a majority of California’s land area did indeed just experience a record-hot summer, the majority of California’s population likely did not (a pattern we’ve seen repeated in several recent years). The millions of folks living in and near Las Vegas and Phoenix, however, were not so lucky.”

Swain further explained that this week’s heatwave will be one of the largest in over a month, impacting areas along the entire West Coast and extending into British Columbia. “Temperatures will be at least 5–10 F above average virtually everywhere (even along the immediate coast) and as much as 15–20 degrees above average inland. While I don’t expect any record-shattering heat with this event, unlike back in July, there may be some daily records.”

“This heat event will actually be the most notable of the year so far in coastal SoCal, where temperatures will make it into the upper 90s within just a few miles of the beaches and could locally end up as hot as 110-115 F in portions of the San Fernando Valley,” he added.

Swain also mentioned potential wildfire risks due to increased temperatures: “[Later in early September], it’s probably simpler to list the areas that I think will not see substantially increased wildfire activity in the coming days.”

The YouTube ‘Office Hours’ session with Daniel Swain can be accessed today at 2 p.m. PT / 5 p.m. ET.