Fire Weather Outlook Discussion
Issued by NWS
FNUS21 KWNS 291544
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1043 AM CDT Sat Apr 29 2017
Valid 291700Z - 301200Z
...CRITICAL FIRE WEATHER AREA FOR FAR SOUTHWESTERN NEW MEXICO AND
FAR SOUTHEASTERN ARIZONA...
...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE LOWER COLORADO
A few spatial adjustments have been made to the ongoing forecast.
Portions of far west Texas were removed from the ongoing critical
based on morning observations, which indicated that cooler air had
filtered into the region from the north. Some warming/drying may
occur later in the afternoon in this region, although it appears
that conditions will not meet temporal critical thresholds in that
area today. The critical in southeastern Arizona and southwestern
New Mexico remains in tact, however, and elevated fire weather
conditions are possible east of this area from the Transpecos to
near San Angelo, Texas.
Farther west, minor spatial alterations to the critical were made in
the Lower Colorado River Valley, where critical atmospheric
conditions (20+ mph northerly surface flow and <10% RH) are expected
for several hours this afternoon amidst dry fuels.
Elevated fire weather conditions remain likely today in portions of
the Florida Peninsula.
See the previous discussion below for more information.
.PREV DISCUSSION... /ISSUED 0214 AM CDT Sat Apr 29 2017/
In the mid levels, a deep cyclone and attendant band of strong flow
aloft are forecast to track from portions of the southwest States to
the southern Great Plains. An area of dry conditions/low RH will
extend from portions of the southwest States to southwest Texas,
which will be overtaken by a cold front advancing southward and
southeastward across portions of the southern Rockies vicinity and
southern High Plains. During the afternoon, the strong winds aloft,
overlying the low RH, will support elevated to critical fire-weather
conditions as vertical mixing strengthens.
...Portions of southeast AZ, southern NM, the Trans-Pecos region of
Westerly to northwesterly winds of 20-30 mph -- strongest across
portions of the TX Trans-Pecos region -- are forecast to combine
with minimum RH of 6-15 percent amid dry fuels. As a result, a
Critical area is in effect. This will be supported by diurnally
enhanced vertical mixing amid a core of strong flow aloft trailing
to the west/southwest of the deep mid-level cyclone.
...Portions of the lower CO River Valley...
A separate area of strong winds -- 20-25 mph from the north -- is
expected to combine with minimum RH of 7-12 percent amid dry fuels
in support of an added Critical area. This will be supported by
diurnally enhanced vertical mixing amid a northerly component to the
strong flow aloft to the west of the deep mid-level cyclone.
...Surrounding the two Critical areas, from portions of the lower CO
River Valley eastward across portions of AZ into southern NM and
Surrounding the Critical areas, elevated to perhaps borderline-
critical fire-weather conditions are anticipated. Despite low RH
across portions of AZ outside of the Critical areas, winds are not
expected to be sufficiently strong for critical designation. Across
portions of southwest TX (to the east of the eastern Critical area),
generally higher RH is expected limit the critical fire-weather risk
despite areas of strong winds.
...Portions of the central FL Peninsula...
Easterly to southeasterly winds of 10-15 mph are forecast to combine
with minimum RH around 35-40 percent amid dry fuels, resulting in
elevated fire-weather conditions. Without stronger winds and lower
RH, critical fire-weather conditions are unlikely.
...Southern CA coastal ranges and adjacent foothills...
Enhanced northeasterly winds are forecast to combine with low RH,
resulting in elevated to critical meteorological conditions.
However, fuels are not expected to be sufficiently dry to warrant
elevated or critical designation.
...Please see www.spc.noaa.gov/fire for graphic product...