...PARTICULARLY DANGEROUS SITUATION (PDS) RED FLAG WARNING IN
EFFECT NOON TUESDAY UNTIL 4 PM WEDNESDAY DUE TO DAMAGING NORTH TO
NORTHEAST WINDS AND LOW HUMIDITIES FOR THE FOLLOWING AREAS: SAN
GABRIEL MOUNTAINS/ SAN GABRIEL AND SAN FERNANDO VALLEYS
(ESPECIALLY FOOTHILLS)/ BEVERLY AND HOLLYWOOD HILLS/ COASTAL AREAS
ADJACENT TO SEPULVEDA PASS / SANTA MONICA MOUNTAINS / SANTA SUSANA
MOUNTAINS / MALIBU / EASTERN VENTURA VALLEY (MAINLY NEAR SIMI
VALLEY/MOORPARK) -- THIS WILL LIKELY BE A LIFE THREATENING,
DESTRUCTIVE, AND WIDESPREAD WINDSTORM...
...RED FLAG WARNINGS IN EFFECT FOR LOS ANGELES COUNTY AND MUCH OF
VENTURA COUNTY -- SEE TIMINGS IN HEADLINES BELOW...
...RED FLAG WARNING IN EFFECT FOR SANTA BARBARA MOUNTAINS
INCLUDING EASTERN SANTA YNEZ RANGE TUESDAY INTO WEDNESDAY...
***THIS IS A PARTICULARLY DANGEROUS SITUATION (PDS) FOR PORTIONS
OF LOS ANGELES AND VENTURA COUNTIES!***
.A very strong, widespread, and destructive north to northeast
windstorm will bring Extremely Critical fire weather conditions to
many areas of Los Angeles and eastern Ventura counties Tuesday
afternoon into early Wednesday afternoon. This is a PARTICULARLY
DANGEROUS SITUATION (PDS) Red Flag Warning event in many areas,
with the combination of very strong upper level wind support,
tightening offshore pressure gradients (LAX-Daggett peaking at
-7 to -8 mb), and moderate cold air advection. The strongest winds
with this event are expected to be Tuesday afternoon into early
Wednesday afternoon when widespread damaging wind gusts of 50 to
80 mph are likely. The San Gabriel mountains, Santa Susana
mountains, and foothills of the San Gabriel/San Fernando Valleys
will likely see areas of destructive wind gusts between 80 and
100 mph! Due to the very strong upper level wind support and high
risk for strong mountain wave activity, typical wind sheltered
areas such as portions of the LA basin and San Gabriel Valley.
The strong winds will likely result in widespread downed
trees/powerlines, as well as widespread power outages. THIS WILL
LIKELY BE THE MOST DESTRUCTIVE WINDSTORM SEEN SINCE 2011
WINDSTORM THAT DID EXTENSIVE DAMAGE TO PASADENA AND NEARBY
FOOTHILLS OF THE SAN GABRIEL VALLEY. ANY COMMUNITIES ALONG
HIGHWAY 118 AND 210 CORRIDORS WILL BE AT HIGHEST RISK FOR
COMPARABLE WIND DAMAGE. Humidity levels are also expected to
lower to between 10 and 15 percent in many areas by Tuesday
afternoon/evening, potentially lowering into single digits in
some areas by late Tuesday night into Wednesday.
The offshore winds are now expected to arrive early Tuesday
morning, resulting in the Red Flag Warning area being moved up to
4 am Tuesday in many areas. AREAS IN A RED FLAG WARNING
(ESPECIALLY DURING THE PDS TIME FRAME) WILL HAVE INCREASED RISK
FOR LARGE FIRES WITH VERY RAPID FIRE SPREAD, EXTREME FIRE
BEHAVIOR, AND LONG RANGE SPOTTING. While the longer duration of
strong winds and Red Flag conditions is expected to be focused
across Los Angeles and Ventura counties, there is now expected to
be a shorter duration of Red Flag conditions across the mountains
of Santa Barbara county Tuesday into Wednesday. Long duration Red
Flag Warnings are in effect for much of Los Angeles and Ventura
counties Tuesday through Thursday, with Fire Weather Watches in
effect Thursday night into Friday.
...FIRE WEATHER WATCH REMAINS IN EFFECT FROM THURSDAY EVENING
THROUGH FRIDAY AFTERNOON FOR POTENTIAL WEAK TO MODERATE OFFSHORE
WINDS AND LOW RELATIVE HUMIDITY FOR MUCH OF LOS ANGELES AND
VENTURA COUNTIES...
* WINDS...Strong/damaging north to northeast winds Tuesday into
Wednesday, likely peaking in many areas between Tuesday
afternoon and Wednesday morning when there is the potential for
strong mountain wave wind activity. During this peak, sustained
winds of 35 to 50 mph and widespread damaging gusts of 50 to 70
mph can be expected. Moderate north to northeast winds will
likely persist Thursday with gusts of 30 to 50 mph, with some
weakening possible by Friday.
* RELATIVE HUMIDITY...Humidities 20 to 30 percent early Tuesday
morning, falling to 10 to 20 percent by late Tuesday
afternoon/evening. Humidities will potentially fall to single
digits in some areas from Wednesday into Friday.
* IMPACTS...If fire ignition occurs, conditions are favorable
for very rapid fire spread and extreme fire behavior,
including long range spotting, which would threaten life and
property. There will be a high risk for widespread downed
trees and powerlines, as well as widespread power outages.
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.
A Fire Weather Watch means that critical fire weather conditions
are likely to occur in the coming days. Residents near wildland
interfaces should prepare now on what to do if a wildfire breaks
out. See readyforwildfire.org and wildfirerisk.org for
information.