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Click for Day 1 FireWX Areal Outline Product
ZCZC SPCFWDDY1 ALL
FNUS21 KWNS 150658
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0158 AM CDT Mon Oct 15 2018
Valid 151200Z - 161200Z
...EXTREMELY CRITICAL FIRE WEATHER AREA FOR PORTIONS OF VENTURA AND
LOS ANGELES COUNTIES IN SOUTHERN CALIFORNIA...
...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN CALIFORNIA...
...Synopsis...
...High-end critical to extremely critical fire weather conditions
will occur across parts of southern CA today with extreme rates of
fire spread possible...
A portion of a positively tilted large-scale upper trough extending
from the Upper Midwest to the northern and central Plains/Rockies
and Great Basin will close off over AZ and adjacent portions of
northern Mexico today. Strong low to mid level northeasterly winds
of 40-60+ kt will be present over parts of southern CA through much
of the period. At the surface, a large area of high pressure will
encompass the Great Basin into the southern/central Rockies and
adjacent Plains.
...Portions of Southern CA...
The LAX-TPH pressure difference has already strengthened to -10 mb
per 05Z observations, and a few locations in the higher terrain of
Ventura and Los Angeles counties in southern CA are showing
northeasterly winds of 20-32 mph with gusts to 43 mph early this
morning. As the pressure gradient continues to strengthen, more
widespread east-northeasterly winds of 20-40 mph will develop
through the day across a greater portion of coastal southern CA,
along with critically reduced RH values of 4-15%. Stronger wind
gusts of 45-65 mph will occur in the higher terrain and favored
passes/canyons as the enhanced low to mid-level flow mentioned
previously reaches the surface through diurnal mixing/heating of the
boundary layer.
Extremely critical conditions (sustained winds of 30-40 mph and RH
values less than 10%) appear likely for parts of Ventura and Los
Angeles counties, especially in the mountains and foothills, as
these locations will be beneath the strongest mid-level winds
through this afternoon. The ongoing extremely critical area has been
expanded to include more of Ventura and Los Angeles counties per
consensus of latest high-resolution guidance. Extreme rates of fire
spread will occur in areas of dry/receptive fuels with any new fire
starts.
Given the expected meteorological conditions, the surrounding
critical area for much of coastal southern CA has been maintained
with just a small northward expansion into parts of Santa Barbara
and San Luis Obispo counties. Sustained winds of 20-30 mph and RH
values of 4-15% will be common across the critical delineation. Even
with some prior precipitation across parts of southern CA, all
available fuel guidance indicates live fuel moisture will be low
enough and fine fuels will be dry enough to support large to extreme
rates of fire spread.
...Portions of Northern CA...
Elevated to locally critical fire weather conditions should persist
for a few hours today across parts of the Sacramento Valley and
vicinity as the surface pressure gradient will remain sufficiently
strong through the early afternoon. Sustained northerly to easterly
winds of 15-20 mph and lowered RH values of 5-15% are expected. The
surface pressure gradient will relax across this region by early
evening, with a corresponding decrease in winds lessening the
overall fire weather threat.
..Gleason.. 10/15/2018
...Please see www.spc.noaa.gov/fire for graphic product...