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886
FNUS28 KWNS 282206
FWDD38

Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0506 PM CDT Tue Mar 28 2017

Valid 301200Z - 051200Z

An active period for fire weather conditions will exist throughout
the extended forecast period, with at least low-end critical
potential on multiple days through at least D8/Tue Apr 4.  A
powerful mid-level jet will dive southward from California into
southern Arizona on D3/Thu, resulting in what will eventually become
a closed low over the Four Corners and southern Plains that will
persist through D6/Sun across these regions.  This low will be
responsible for enhanced mid-level flow in portions of the region
throughout the period that will contribute to the fire weather
threats on these days.  Beyond D6/Sat, models eject the closed low
over the southern tier of the U.S. while keeping enhanced mid-level
flow across the Southwest and Southern Rockies amidst several
low-amplitude shortwaves that will traverse the region.  Model
agreement on specific timing and placement of these waves is
relatively poor, but enough agreement exists on the overall synoptic
pattern to highlight areas on the D7/Mon and D8/Tue Apr 4 time
frames with low probabilities.

...D3/Thu and D4/Fri - Portions of the Southwest eastward to the
Southern Plains...
The aforementioned powerful mid-level jet entering the region will
be the primary impetus for enhanced fire weather concerns during
these periods.  A favorable surface pressure gradient, combined with
vertical mixing processes, will foster the development of widespread
areas of 20+ mph surface flow on both days.  A D3/Thu critical area
has been introduced in this forecast for portions of southeastern
Arizona and southwestern New Mexico based on increased confidence of
20-25 mph winds (with higher gusts) occurring amidst dry low-level
conditions during this period.  40% probabilities exist as far west
as the Lower Colorado River Valley, where particularly strong
surface flow may develop amidst a modestly dry low-level airmass,
although questions regarding fuel receptiveness preclude higher
probabilities at this time.  More extensive, and potentially
higher-end, fire weather conditions will exist in portions of New
Mexico and west Texas on D4/Fri as a dry sector develops across
portions of this region southwest of a deepening Plains surface low.

...D5/Sat and D6/Sun - Southeastern New Mexico and Portions of West
Texas...
The cut off low responsible for critical conditions in previous days
will slowly depart the region during this time period, with enough
of a lingering pressure gradient and low-level warming/drying for
locally critical fire weather conditions in these regions.  A cooler
airmass will filter into portions of Texas on D6/Sun and keep the
driest conditions focused along the Rio Grande River Valley, where
40% probabilities were maintained.

...D5/Sat - Portions of the Lower Colorado River Valley...
Models indicate enough lingering low-level flow in the region for at
least elevated fire weather conditions in the region.  A 40%
delineation has been added to the forecast to address this threat.

...D7/Mon and D8/Tue Apr 4 - Portions of the Southern Rockies and
adjacent Plains...
As mentioned previously, enough confidence exists in the overall
synoptic pattern being favorable for at least low-end fire weather
conditions to highlight areas with low (40%) probabilities.  These
regions will be revised in later forecasts as details regarding the
synoptic pattern become clearer.

..Cook.. 03/28/2017

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

$$



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