Headline:
Red Flag Warning issued December 10 at 9:06AM PST until December 10 at 2:00PM PST by NWS Los Angeles/Oxnard CA
Event:
Red Flag Warning
Urgency:
Expected
Effective:
December 10, 2024 - 9:06am
Expires:
December 10, 2024 - 2:00pm
Description:
...PARTICULARLY DANGEROUS SITUATION (PDS) RED FLAG WARNING IN
EFFECT UNTIL 2 PM TODAY DUE TO DAMAGING SANTA ANA WINDS AND VERY
LOW HUMIDITIES FOR THE FOLLOWING AREAS: SAN GABRIEL MOUNTAINS/
SANTA MONICA MOUNTAINS/ SANTA CLARITA VALLEY/ CALABASAS/ VENTURA
COUNTY COASTS AND VALLEYS/ WESTERN SAN FERNANDO VALLEY -- AND RED
FLAG WARNINGS IN EFFECT FOR ALL OTHER TIMES UNTIL 6 PM WEDNESDAY
IN THESE SAME AREAS...
...PARTICULARLY DANGEROUS SITUATION (PDS) RED FLAG WARNING IN
EFFECT UNTIL 10 AM WEDNESDAY DUE TO DAMAGING SANTA ANA WINDS AND
VERY LOW HUMIDITIES FOR THE FOLLOWING AREAS:
SANTA SUSANA MOUNTAINS-- AND RED FLAG WARNINGS IN EFFECT FOR ALL
OTHER TIMES UNTIL 6 PM WEDNESDAY IN THIS SAME AREA...
...PARTICULARLY DANGEROUS SITUATION (PDS) RED FLAG WARNING IN
EFFECT UNTIL 2 PM TODAY DUE TO DAMAGING SANTA ANA WINDS AND VERY
LOW HUMIDITIES FOR THE FOLLOWING AREAS:
VENTURA COASTAL PLAIN (ESPECIALLY FOOTHILLS)/ MALIBU COAST -- AND
RED FLAG WARNINGS IN EFFECT FOR ALL OTHER TIMES FROM 2 PM MONDAY
UNTIL 2 PM WEDNESDAY IN THESE SAME AREAS...
...RED FLAG WARNING IN EFFECT UNTIL 6 PM WEDNESDAY FOR VENTURA
MOUNTAINS, I5 CORRIDOR, EASTERN SAN FERNANDO VALLEY, AND SAN
GABRIEL VALLEY DUE TO GUSTY SANTA ANA WINDS AND VERY LOW
HUMIDITIES...
...RED FLAG WARNING IN EFFECT UNTIL 10 PM THIS EVENING FOR THE
SAN LUIS OBISPO COUNTY MOUNTAINS DUE TO GUSTY EAST TO SOUTHEAST
WINDS AND VERY LOW HUMIDITIES...
...RED FLAG WARNING IN EFFECT UNTIL 2 PM TODAY FOR THE CHANNEL
ISLANDS AND PALOS VERDES DUE TO GUSTY SANTA ANA WINDS AND VERY LOW
HUMIDITIES...
***THIS IS A PARTICULARLY DANGEROUS SITUATION (PDS) FOR MANY
AREAS OF LOS ANGELES AND VENTURA COUNTIES ***
A strong, widespread, and long duration Santa Ana event will
bring widespread critical to extremely critical fire weather
conditions to many areas of Los Angeles and Ventura counties
through Wednesday. This will be a PARTICULARLY DANGEROUS
SITUATION (PDS) Red Flag Warning event in many areas, with the
combination of a strong offshore pressure gradient, strong cold
air advection, and moderate upper level wind support.
As surface high pressure builds into the Great Basin, Santa Ana
winds will continue today into Wednesday, peaking through early
this afternoon. The offshore winds are expected to diminish some
by Wednesday, but a very dry air mass will persist. With the
strong likelihood of widespread single digit humidities with this
event, there is high confidence for a long duration Red Flag
event. In addition, there is high confidence of PDS Red Flag
Warning conditions through early this afternoon, as damaging wind
gusts of 60 to 80 mph will likely overlap with single digit
humidities across many of the windier mountain and foothill areas.
Peak gusts of 40 to 65 mph will also affect most wind prone
coastal and valley areas of Los Angeles and Ventura counties. With
the threat of damaging wind gusts in these windier corridors,
there will be an increased risk for downed trees and powerlines,
along with power outages.
The hardest hit areas will likely be the San Gabriels, Santa
Susanas, western Santa Monicas into Malibu, Ventura county
valleys (especially Simi Valley and Moorpark), western San
Fernando Valley (especially Highway 118/210 corridors from Porter
Ranch to San Fernando), and the hills above Camarillo into east
Ventura. Due to the expected long duration of dangerous fire
weather conditions and critically dry fuels, there is an
increased risk for any new ignitions to have very rapid fire
spread and extreme fire behavior (including long range spotting).
As a result, there is the increasing threat for fire weather
conditions to rival other historical fires in recent times
including the Mountain and Thomas Fires. Dry offshore conditions
will likely persist into Thursday morning, with a return of
onshore flow and some humidity recovery in the afternoon.
* WINDS...Santa Ana winds will peak this morning, with wind speeds
of 25 to 35 mph gusting to 45 to 60 mph expected. The strongest
winds will be focused across higher terrain.
* RELATIVE HUMIDITY...Widespread humidities of 5 to 10 percent.
* IMPACTS...If fire ignition occurs, conditions are favorable
for large fires with very rapid fire spread, extreme fire
behavior, and long range spotting, which would threaten life
and property. There is also the risk of locally damaging winds.
Instruction:
A Red Flag Warning means that critical fire weather conditions
are either occurring now, or will shortly. Use extreme caution
with anything that can spark a wildfire. Residents near wildland
interfaces should be prepared to evacuate if a wildfire breaks
out. See readyforwildfire.org and wildfirerisk.org for
information.
Area Description:
San Miguel and Santa Rosa Islands; Santa Cruz and Anacapa Islands
Forcast Office:
NWS Los Angeles/Oxnard CA