ZCZC SPCFWDDY1 ALL
FNUS21 KWNS 070737
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0137 AM CST Tue Jan 07 2025
Valid 071200Z - 081200Z
...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN CALIFORNIA...
...Synopsis...
A broad trough across the West will undergo intensification today. A
strong mid-level jet will develop in the western Great Basin and
California. At the surface, high pressure will strengthen in the
Great Basin into the lower Colorado River Valley.
...Southern California...
The offshore pressure gradient may be sufficient to support elevated
to critical fire weather by this afternoon. RH will be the main
uncertainty during the afternoon, but around 20% appears likely and
near 15% is certainly possible. Winds this afternoon will peak at
20-25 mph outside of the terrain. Both the offshore gradient and the
supporting upper-level winds are expected to increase in magnitude
during the evening/overnight into Wednesday morning. The strongest
upper-level winds (and thus wind gusts) are most likely around very
late today to early Wednesday. How low RH will remain overnight is
also somewhat uncertain, but wind strength (25-35 mph) would still
support higher-end critical conditions in the typical Santa Ana
corridors in LA/Ventura Counties.
..Wendt.. 01/07/2025
U.S. Day 2 Fire Weather Outlook
ZCZC SPCFWDDY2 ALL
FNUS22 KWNS 070738
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0138 AM CST Tue Jan 07 2025
Valid 081200Z - 091200Z
...EXTREMELY CRITICAL FIRE WEATHER AREA FOR PORTIONS OF LOS ANGELES
AND VENTURA COUNTIES...
...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN CALIFORNIA...
...Synopsis...
A cutoff upper low pressure system within the lower Colorado River
Valley into the Gulf of California will slowly continue to sag
southeastward on Wednesday. A strong mid-level jet will remain
favorably oriented with offshore winds in southern California
through mid-afternoon. A strong surface high, though weakening
through the day, should remain sufficiently intense to drive strong
offshore surface winds across southern California.
...Southern California...
Strong surface winds of 25-40 mph (with significant wind gusts
within the terrain-favored areas) are expected during the morning
into at least the early afternoon. While some locations may
experience some RH recovery overnight, RH will begin to drop to
around 10-15% as temperatures rise during the day. Given the
intensity of the winds, extreme fire behavior appears likely should
ignitions occur. Extremely critical fire weather is most likely for
portion of Los Angeles and Ventura Counties. With high pressure
extending farther south than on Monday, critical fire weather will
extend to the San Diego vicinity as well. Even though the
upper-level winds will weaken along with the offshore gradient,
elevated to critical fire weather is expected to continue into
Thursday morning.
..Wendt.. 01/07/2025
U.S. Day 3-8 Fire Weather Outlook
ZCZC SPCFWDD38 ALL
FNUS28 KWNS 062149
Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0349 PM CST Mon Jan 06 2025
Valid 081200Z - 141200Z
Critical fire weather conditions are expected along the southern
California coast at the start of the extended period before a
relatively quiescent period of limited fire weather concerns across
the country - largely driven by recent widespread precipitation and
cold temperatures across the country.
..D3/Wednesday to D4/Thursday - Southern California...
Critical fire weather conditions will likely be ongoing at the start
of the forecast period/12 UTC Wednesday along the southern CA coast.
Latest water-vapor imagery depicts an upper ridge building along the
West Coast with an embedded shortwave trough propagating southward
across the Pacific Northwest. This shortwave will amplify over the
next 48 hours as it migrates into the lower CO River Valley. A
building surface high over the Great Basin coupled with
strengthening offshore mid-level winds will induce a strong,
prolonged offshore wind event along the southern CA coast beginning
on D2/Tuesday and persisting into D4/Thursday.
Medium-range deterministic guidance suggests widespread sustained
winds between 25-35 mph are expected with gusts between 50-60 mph
possible within the coastal terrain. While 25+ mph winds are
expected for much of the day, the general ensemble consensus
continues to indicate that the peak offshore pressure gradient will
occur on Wednesday morning, which may support isolated gusts upwards
of 70-80 mph in terrain favored areas. Relative humidity reductions
down to 10-15% are expected, and a few locations may see RH values
fall into the upper single digits. As such, some locations may
experience periods of extremely critical fire weather conditions
Wednesday morning and afternoon.
Wind speeds will gradually abate beginning early Thursday morning
into early Friday as the upper wave shifts east. Model spread
regarding the cessation of critical fire weather conditions remains
high, but critical wind speeds will likely persist within the higher
terrain of Los Angeles and Ventura counties through Thursday
morning. Consequently, 70% risk probabilities have been introduced,
and may need to be expanded as confidence in the wind forecast
increases.
..Moore.. 01/06/2025