U.S. Day 1 Fire Weather Outlook
ZCZC SPCFWDDY1 ALL
FNUS21 KWNS 141644
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1044 AM CST Tue Jan 14 2025
Valid 141700Z - 151200Z
...EXTREMELY CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE WESTERN
LA BASIN...
...CRITICAL FIRE WEATHER AREA FOR MUCH OF SOUTHERN CA...
...17z Update...
Morning obs show offshore flow has been slow to develop across
western Ventura and LA Counties. Stronger gusts of 50-60 mph were
noted in the western San Gabriel mountains, and should become more
common across the higher terrain through the afternoon. As
mechanical mixing increases with diurnal heating, stronger winds
should also develop across much of southern CA. Sustained 20-30 mph
winds with RH below 20% is expected across the Ventura Plain and
interior Valleys this afternoon, as upper-level winds become aligned
with offshore gradients. This should promote several hours of
high-end critical to localized extremely critical conditions through
terrain-favored corridors. Critical fire concern should continue
overnight as winds strengthen again into early D2/Wed morning. The
prior outlook area is unchanged, see the previous discussion for
more info.
..Lyons.. 01/14/2025
.PREV DISCUSSION... /ISSUED 0152 AM CST Tue Jan 14 2025/
...Synopsis...
A belt of stronger northeasterly mid-level flow will overspread
southern California as a 500 mb cut-off low attempts to drift
southwest from the coastline today. A localized tightening of the
surface pressure gradient is likely during the morning hours,
encouraging very strong, dry offshore flow from the Ventura Valley
to the Laguna Mountains. Widespread 20-30 mph sustained offshore
winds are likely (perhaps with gusts exceeding 50 mph at times) for
much of the period, warranting the maintenance of Critical
highlights. Similar to yesterday, the best chance for sustained
30-40 mph winds amid 10 percent RH will be from around the Ventura
Valley to the San Bernardino Mountains. Here, Extremely Critical
highlights remain given the potential for very dangerous
wildfire-spread conditions and the potential for extreme fire
behavior.
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U.S. Day 2 Fire Weather Outlook
ZCZC SPCFWDDY2 ALL
FNUS22 KWNS 141919
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0119 PM CST Tue Jan 14 2025
Valid 151200Z - 161200Z
...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN CA...
...19z Update...
Confidence continues to increase that strong offshore winds and
high-end critical fire-weather conditions will be ongoing at the
start of the period D2/Wed morning. A belt of 25-35 kt mid-level
east-northeasterly flow, will gradually become more easterly and
align with a pronounced offshore pressure gradient across southern
California. This should support sustained 25-35 mph surface winds
and RH near 10% across the western LA Basin Santa Ana corridors.
Stronger gusts to 40-50 mph will also be possible across the higher
terrain. Fire-weather concerns will remain high through the day
before winds decrease overnight into D3/Thurs. See the prior outlook
for more info.
..Lyons.. 01/14/2025
.PREV DISCUSSION... /ISSUED 0208 AM CST Tue Jan 14 2025/
...Synopsis...
A belt of stronger mid-level east-northeasterly flow, along with
surface high pressure over the Great Basin, will continue to support
a pronounced pressure gradient across southern California, where dry
offshore flow will remain a concern for most of the Day 2
(Wednesday) period. Latest guidance consensus shows at least 25 mph
sustained winds amid 10-20 percent RH across terrain favoring areas
from the Ventura Valley to the Laguna Mountains. These conditions
are most likely during the first half of the period, with Critical
highlights added to address the wildfire-spread potential.
U.S. Day 3-8 Fire Weather Outlook
ZCZC SPCFWDD38 ALL
FNUS28 KWNS 132142
Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0342 PM CST Mon Jan 13 2025
Valid 151200Z - 211200Z
Widespread and high-end critical fire-weather concerns are expected
to persist through midweek this week over portions of southern CA. A
strong upper low and easterly mid-level flow are forecast to develop
off the Pacific Coast. As the upper low cuts off, mid-level flow
will align with strong offshore pressure gradients over the western
LA Basin and mountains through D4/Thur. Winds will then slowly
weaken through the remainder of the week. High pressure redevelops
this weekend and additional fire-weather concerns are possible.
...Southern CA...
Strong offshore winds are expected to be ongoing at the start of the
forecast period D3/Wed morning. Sustained 25-40 mph with gusts of
45-70 mph and single digit RH will likely support extreme fire
danger across portions of the western LA Basin and Transverse ranges
through noon. Critical fire-weather conditions will likely continue
into D3/Wed afternoon with strong winds and low RH. Offshore
gradients will gradually weaken into the evening as the upper low
shifts southeastward. Upper-level flow is also forecast to slowly
weaken into early D4/Thursday. The winds aloft are forecast to
become more southeasterly as they weaken. This shift should favor
less alignment with typical Santa Ana corridors in the LA Basin.
Still, elevated to critical conditions will likely persist across
the Santa Monica and Santa Ynez Mountains through D4/Thurs before
winds weaken below 25 mph.
Fire-weather concerns will lessen through the remainder of the work
week as onshore flow returns on the backside of the upper low.
However, high pressure over the Great Basin is forecast to
strengthen again this weekend and into week 2, as an arctic air mass
intrudes the lower 48. This could support another prolonged period
of offshore flow and heightened fire-weather concerns. However,
confidence in the strength of any offshore winds later in the period
is low.
..Lyons.. 01/13/2025
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