…FIRE WEATHER WATCH IN EFFECT FROM TUESDAY MORNING THROUGH
THURSDAY EVENING FOR GUSTY SANTA ANA WINDS AND LOW RELATIVE
HUMIDITY FOR MUCH OF CENTRAL/WEST-CENTRAL/SOUTHWEST LOS ANGELES
COUNTY AND CENTRAL/EAST-CENTRAL/SOUTHERN VENTURA COUNTY…
.Confidence continues increasing that the weather pattern next week will
become favorable for elevated to critical fire-weather conditions
across Santa Ana wind-prone areas of Los Angeles and Ventura Counties,
as well as portions of Santa Barbara County prone to north-wind
enhancements. Next week, an upper-level ridge is forecast to gradually
build along the Pacific coast to the west of a large upper trough
encompassing much of the central and eastern states. Correspondingly,
surface high pressure strengthening over the Great Basin will facilitate
increasing offshore flow amid slight to moderate upper support, which
will combine with unseasonably warm temperatures assisted by the
building upper ridge to produce the increased fire-weather risk. LAX-
Bakersfield offshore gradients are currently forecast to reach 5-7 mb
starting Monday, with LAX-Daggett offshore gradients reaching 4-5 mb
starting Tuesday. Given the enhanced northerly pressure gradients, wind
directions could be 10-20 degrees more northerly than easterly for this
event compared to other November and December 2024 events, especially
early on for this next event.
The greatest potential for critical fire-weather conditions will include
areas prone to a moderate Santa Ana wind event, for Tuesday through
next Thursday. This includes much of Central/West-Central/Southwest Los
Angeles County and Central/East-Central/Southern Ventura County.
Strengthening consensus among weather-model solutions regarding the
pattern favoring critical fire-weather conditions has warranted the
issuance of the Fire Weather Watch.
Regarding alternate scenarios, there is a 60% chance for fire-weather
headlines to be expanded to include the eastern San Gabriels, northwest
Los Angeles County Interstate-5 corridor, and northern Ventura County
mountains. In addition, the enhanced northerly gradients may tend to
expand the fire-weather risk to the east of areas more typically prone
to a moderate Santa Ana wind event, to also include areas from Hollywood
to Beverly Hills and Santa Monica — Confidence: lower chance at 40%
for fire-weather headlines. Elevated to brief critical fire-weather
conditions will also be a concern farther west across the Santa
Barbara County mountains and especially the Santa Ynez range when
northerly pressure gradients are strongest on Monday and Tuesday,
though humidities will likely remain elevated — Confidence:
even smaller but non-zero chance at 20% for fire-weather headlines.
The National Weather Service in Los Angeles/Oxnard has issued a
Fire Weather Watch for gusty Santa Ana winds and low relative
humidity, which is in effect from Tuesday morning through Thursday
evening.
* WINDS…North to northeast winds gusting to 35 to 55 mph.
* RELATIVE HUMIDITY…Relative humidities 10 to 20 percent Tuesday
decreasing to 5 to 15 percent by Thursday.
* IMPACTS…If fire ignition occurs, conditions are favorable for
rapid fire spread and extreme fire behavior which would threaten
life and property.