SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0238 PM CDT Tue Oct 01 2019
Valid 021200Z - 031200Z
Locally critical surface wind/RH conditions still appear possible
across portions of central Colorado within the elevated delineation,
with temperatures still appearing to be on the cool side. The cooler
temperatures, and 20+ mph sustained winds being confined to terrain
favoring areas precludes a critical delineation at this time.
Similarly, locally critical conditions in the mountains and
foothills of southern California still appear possible both early
Wednesday morning, and then again late Wednesday evening. Both the
localized and brief nature of the critical conditions continue to
preclude a critical area addition here as well.
Relatively dry, breezy conditions are also possible across parts of
the lower Ohio Valley into the Mid-Atlantic late Wednesday afternoon
in advance of an approaching cold front. While wind/RH are expected
to remain generally below elevated criteria in these regions,
abnormally high surface temperatures (well over 90F) and drying
fuels associated with a mild to locally moderate short-term drought
may compensate to support localized grass-fire potential.
Otherwise, the previous forecast remains largely on track. Please
see the previous forecast below for more details.
..Squitieri.. 10/01/2019
.PREV DISCUSSION... /ISSUED 1222 AM CDT Tue Oct 01 2019/
...Synopsis...
The western U.S. mid-level trough will continue to evolve into an
open wave while migrating eastward toward the northern High Plains.
Mid-level flow across dry areas of the central Rockies will remain
strong however even as the mid-level jet migrates away from the
region. Mid/upper ridging will remain in place across the
southeastern U.S. throughout the forecast period. Meanwhile at the
surface, high pressure will build into the Great Basin and setup a
modest offshore gradient across coastal ranges of southern
California. A front will make southward progress across the central
Plains as well, though specific timing of this phenomenon is a bit
uncertain.
...Colorado...
Vertical mixing processes beneath stronger flow aloft will encourage
gusty westerly surface winds during peak heating hours even though
surface temperatures will be somewhat cooler than in prior days. 15
mph westerly winds will become common, though this flow will be
stronger in terrain-favored areas and may exceed 20 mph at times.
Meanwhile, critically low RH will develop by afternoon, and a few
locales may fall below 10%. Given dry fuels across the area,
elevated to locally critical fire weather conditions are likely and
an elevated delineation has been introduced for this outlook.
...Southern California...
An offshore surface pressure gradient will develop as high pressure
builds into the Great Basin. Easterly/northeasterly surface flow
will develop and exceed 20 mph at times in terrain-favored areas.
These conditions will occur amidst 20-25% RH values at times,
although winds should weaken some during the day before
strengthening again late D2/Wednesday. These conditions are
consistent with elevated fire weather thresholds and an attendant
delineation has been introduced.
...Please see www.spc.noaa.gov/fire for graphic product...
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