923
FNUS21 KWNS 081632
FWDDY1

Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1031 AM CST Wed Jan 08 2025

Valid 081700Z - 091200Z

...EXTREMELY CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE SOUTHERN
CALIFORNIA COAST...
...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE SOUTHERN
CALIFORNIA COAST...

The previous forecast remains on track with no changes needed.
Recent radar reflectivity trends show an uptick in fire activity
associated with ongoing fires across the Los Angeles county area.
Wind gusts between 40-60 mph remain widespread with more isolated
gusts of 70-85 mph have been observed over the past hour (as of
16:30 UTC). Recent high-res guidance, including experimental WoFS
forecasts, indicate that these winds will continue for a couple more
hours through roughly 18 UTC before gradually abating through the
day (especially after 00 UTC). However, sustained winds between
20-30 mph with frequent gusts above 40 mph will likely continue
through mid afternoon.

Patchy mid to high-level cloud cover over the region will modulate
diurnal insolation to some degree, but RH values currently in the
mid-teens to low 20s should fall into the upper single digits to low
teens through mid-afternoon as downslope warming/drying continues.
Despite a slow reduction in winds, falling RH will be compensatory
in nature and maintain a very high fire weather threat. Fosberg and
Red Flag Threat Index forecasts from both the HREF and WoFS suggests
the peak in fire weather conditions will most likely occur during
the 18-21 UTC period when the temporal overlap of strong gusty winds
and falling RH will be greatest. As such, a multi-hour window of
extremely critical conditions remains likely for portions of Ventura
and Los Angeles counties.

..Moore.. 01/08/2025

.PREV DISCUSSION... /ISSUED 0143 AM CST Wed Jan 08 2025/

...Synopsis...
Water vapor imagery shows the upper-level low now over the lower
Colorado Valley. A belt of strong mid-level winds is now over
southern California. This mid-level jet should remain in the region
through mid morning. Though these winds will weaken through the day,
at least moderate flow will remain aloft. Similarly, the Great Basin
surface high will intensify this morning before weakening slowly.

...Southern California...
A dangerous fire weather event is currently unfolding in portions of
southern California.

As of early this morning, three hot spots (indicating ongoing fires)
are evident in Los Angeles County on shortwave IR imagery. Winds are
currently 20-35 mph with gusts of 50-60 mph (with isolated 70-100
mph gusts). These winds should increase into early/mid morning. RH
of 10-20% should also remain steady until sunrise when RH will drop
further with surface heating.

Extreme fire weather is still expected in portions of the typical
Santa Ana corridors. There is additional potential for localized
extreme conditions near the Santa Ana Mountains in Orange County.
Sustained winds could reach 30-40 mph and RH could fall to 5-10%.
With the surface high pushing farther south today, elevated to
critical fire weather will extent toward the San Diego vicinity.
Critical fire weather farther south should be more limited to the
terrain and the foothills. Ongoing fires and any others that start
will be capable of very rapid spread.

The most extreme fire weather conditions will lessen by the
afternoon. However, critical fire weather conditions should still
persist as the offshore gradient will still remain moderately strong
along with the lingering moderate mid-level winds.

...Please see www.spc.noaa.gov/fire for graphic product...

$$