ZCZC SPCFWDDY1 ALL
FNUS21 KWNS 221537
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1037 AM CDT Fri Sep 22 2017
Valid 221700Z - 231200Z
...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF EASTERN COLORADO...
...Portions of Eastern Colorado...
The critical fire weather area has been expanded north and eastward
this update to account for latest HRRR wind/RH guidance and surface
observation trends this morning. RH values are expected to fall into
the 12-15 percent range in the critical area with sustained wind
speeds in the 20-30 mph range with higher gusts for several hours
this afternoon.
The surrounding elevated area from portions of central NM into the
central High Plains has been adjusted only slightly. See previous
discussion below for more details.
..Leitman.. 09/22/2017
.PREV DISCUSSION... /ISSUED 0134 AM CDT Fri Sep 22 2017/
...Synopsis...
A large-scale upper trough will make only slow eastward progress
across the western CONUS today, while upper ridging remains over
much of the central and eastern states. At the surface, a weak low
will develop northeastward across the northern Plains today, while a
second area of low pressure redevelops across eastern CO. A surface
trough/dryline will extend southward from the low over eastern CO
across the central/southern High Plains.
...Portions of the Central/Southern High Plains...
Strong 40-50 kt mid-level southwesterly winds will be present across
much of the High Plains today in association with the previously
mentioned upper trough over the western CONUS. As diurnal mixing of
the boundary layer occurs, a broad corridor of strong/gusty surface
winds will develop this afternoon from portions of the Southwest
into the eastern Great Basin, central/southern Rockies, and adjacent
High Plains. Sustained south-southwesterly winds of 20-30 mph will
likely occur, with higher gusts possible, particularly in higher
terrain. RH values will become lowered mainly into the 15-25% range
through downslope warming/drying of low levels along/behind a
surface trough/dryline. Latest short-term guidance suggests these
lowered RH values will likely occur across parts of NM, and the
ongoing elevated area has been extended southward to account for
this risk. A small area of critical conditions now appears likely
across parts of southeastern CO for a few hours this afternoon where
RH values will fall into the 12-15% range. Coupled with receptive
fuels, these forecast meteorological conditions warrant the
introduction of a small critical area across parts of southeastern
CO.
...Please see www.spc.noaa.gov/fire for graphic product...
ZCZC SPCFWDDY2 ALL
FNUS22 KWNS 220635
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0135 AM CDT Fri Sep 22 2017
Valid 231200Z - 241200Z
...NO CRITICAL AREAS...
...Synopsis...
A large-scale upper trough/low centered over the Great Basin will
continue to move slowly eastward across the western CONUS on Day
2/Saturday. An upper ridge will persist over much of the eastern
CONUS. While enhanced mid-level winds will remain present over
portions of the Southwest into the High Plains Saturday afternoon,
RH values behind a surface cold front are generally expected to
remain above critical levels. Locally elevated fire weather
conditions may occur across parts of northern AZ and southeastern UT
where RH values could become lowered near 20% in conjunction with
strong/gusty surface winds. However, only marginally receptive to
unreceptive fuels across this region and cooler temperatures behind
the surface cold front preclude the introduction of an elevated area
at this time.
..Gleason.. 09/22/2017
...Please see www.spc.noaa.gov/fire for graphic product...
