Fire Weather Outlook Discussion
Issued by NWS
FNUS22 KWNS 291910
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0209 PM CDT Wed Mar 29 2017
Valid 301200Z - 311200Z
...CRITICAL FIRE WEATHER AREA FOR FAR SOUTHEASTERN ARIZONA INTO
SOUTHWESTERN NEW MEXICO...
...CRITICAL FIRE WEATHER AREA FOR HIGHER TERRAIN OF FAR SOUTHEASTERN
NEW MEXICO AND FAR WEST TEXAS...
A few changes were made to the outlook to expand critical into parts
of eastern Pima/Santa Cruz Counties in Arizona and also add a new
critical area for higher terrain of southeastern New Mexico and far
west Texas. 20+ mph wind speeds will be somewhat more widespread
than previously forecast especially late in the day when
strengthening mid-level flow commences in advance of a very strong
western Great Basin trough. Surrounding these critical areas,
critical wind speeds are likely, but should not last for sufficient
duration to include within critical areas.
Farther west into the Lower Colorado River Valley, wind speeds will
increase dramatically late in the day, perhaps exceeding 50 mph in
portions of southern Nevada and northwestern Arizona. Latest fuels
guidance suggests that dry fuels are not widespread in these areas,
although they are closer to borderline critically dry thresholds
with southward extent into southwestern Arizona/southeastern
California. After coordination with affected local WFOs, an
elevated fire weather delineation was maintained for this outlook to
address the critical atmospheric conditions and sub-critical state
The remainder of the forecast is on track and additional information
is provided in the previous outlook discussion below.
.PREV DISCUSSION... /ISSUED 0145 AM CDT Wed Mar 29 2017/
In the midlevels, a trough will amplify over the Western States
while tracking eastward. An accompanying band of enhanced flow aloft
will begin to overspread antecedent dry surface conditions from
portions of the Southwest States to the southern High Plains,
resulting in elevated to critical fire-weather conditions.
...Portions of the Southwest States to the southern High Plains...
Across the Critical area for portions of southeast AZ and southwest
NM, deep mixed layers will extend into the strengthening flow aloft
to support west-southwesterly to westerly surface winds around 20-22
mph and higher gusts. Furthermore, the deep mixing will support
minimum RH around 8-12 percent amid the strong winds and dry fuels.
Surrounding the Critical area, elevated to borderline-critical
fire-weather conditions are anticipated. Where RH values become
critically low amid dry fuels, critically strong winds are not
expected to occur on any more than a brief basis owing to the
delayed onset of stronger low-level flow relative to peak diurnal
heating. Strong surface winds may affect parts of northwest AZ,
southern NV, and adjacent southeast CA, though relatively higher RH
and/or less-favorable fuels for fire spread preclude Critical
...Please see www.spc.noaa.gov/fire for graphic product...