Brief critical fire weather conditions returned to the Southland’s coastal mountain slopes Wednesday, with more warm, dry weather expected Thursday before a sharp change to the first truly cold days of autumn.
“Big swings in the weather this week, going from near normal temps, to much above normal, to well below normal all in the span of about four days,” the National Weather Service predicted.
Temperatures warmed up to the low 90s in some valley areas Wednesday, with highs of 92 in Northridge and Woodland Hills expected to rise to 94 on Thursday, according to the National Weather Service.
Winds were expected to pick up Wednesday night across L.A. and Ventura counties, though below advisory level, the weather service said. Gusty west to northwest winds are expected starting Friday and lasting off and on through the weekend, with 35- to 55-mph gusts possible Friday night into Saturday.
The brief combination of heat, wind and low relative humidity — 8-15 percent — will increase fire danger, prompting the NWS to warn residents to use extreme caution with potential fire sources. The NWS also warned residents never to leave children, seniors and pets in cars parked in hot weather as vehicle interiors can quickly become hot enough to kill.
The weather service also warned of dangerous sea and surf conditions, with gales of 30-40 knots and 10-20 foot steep seas.
A sharp cooling trend will arrive on Friday and continue into the weekend with a chance of light showers at times. Forecasters said the mountains and eastern L.A. County have the best chances for rain, but it shouldn’t be more than a tenth of inch.
Downtown Los Angeles is expected to see highs of 89 on Thursday, dropping to 72 Friday and 66 by Saturday, according to NWS projections. Van Nuys and Pasadena will also see highs of 66 on Saturday.
The predicted high in Northridge will drop to 74 and 69 Friday and Saturday.
Nighttime lows will begin dropping below 50 degrees across much of L.A. County on Friday and Saturday.
The Antelope Valley, which will see highs in the 80s Wednesday and Thursday, will drop into the upper 50s Friday and Saturday. Lows will dip into the 30s beginning Friday.
In Orange County, Anaheim is expected to reach 91 degrees Thursday before dropping to 73 Friday and 64 on Saturday, while the chillier coastal area of Newport Beach will see its high drop all the way to 60 on Saturday.
The NWS said “a very cold upper low will drop south along the West Coast Friday and usher in a much colder air mass that will stick around for the next several days.”