Fire Weather Outlook Discussion
Issued by NWS
FNUS22 KWNS 271840
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0140 PM CDT Mon Mar 27 2017
Valid 281200Z - 291200Z
...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN NEW MEXICO
AND WEST/SOUTHWEST TEXAS...
Ongoing forecast is generally on track. Considerable uncertainty
remains regarding the evolution of a dryline over west-central
Texas. The latest 12z Euro indicates a westwardly displaced dryline
over portions of west Texas west of Lubbock Tuesday afternoon.
This, in addition to potential for early morning wetting rains in
parts of the region, suggest that the overall fire weather threat
may not evolve as far east as previously indicated. The elevated
area has been moved westward slightly as a result, although the
critical area will remain unchanged for this outlook.
Observations/trends will be monitored for additional changes that
may be needed to the outlook in later updates.
More details are in the previous discussion (see below).
.PREV DISCUSSION... /ISSUED 0256 AM CDT Mon Mar 27 2017/
A strong mid-level trough across the southwest United States will
continue to close off early in the forecast period as it slowly
moves across the southern Rocky Mountains and into the southern
Plains. Accompanying this trough/low will be a very strong mid-level
jet. As this jet overspreads the Plains, a surface-low pressure is
expected to deepen as it lifts northeast from southeast New Mexico
toward western/central Oklahoma. Strong downslope flow, coupled with
a deepening surface low, will help to sharpen a north-south dryline
across portions of the Texas Panhandle and west Texas Tuesday
...Far southeast Arizona east to West Texas...
Diurnally driven vertical mixing will allow for downward momentum
transfer of the strong mid-level jet during the forecast period.
This, coupled with a tightening surface-pressure gradient will
result in strong, gusty westerly winds across much of the area. At
this time, relative humidity should remain above 20% across
southeast Arizona and southwest New Mexico except on brief/spotty
basis. This will result in elevated fire-weather conditions here.
Farther east, across eastern New Mexico and far West Texas,
downslope flow will aid the establishment of a low-level thermal
axis stretching from the Big Bend Country northward into eastern New
Mexico and far West Texas. Here, surface winds are expected to be
between 20-30 mph with relative-humidity values falling into the
7-15% range. This will result in critical fire-weather conditions.
The eastward extent of critical fire-weather conditions will be
heavily influenced by the exact evolution and location of the
surface dryline. At this time, areas delineated by critical
conditions are those with highest confidence of seeing critical
conditions. To the east, elevated delineation has been used to
indicate locations that will experience strong surface winds, but
given uncertainties in dryline location, confidence in
relative-humidity values reaching critical thresholds is lower.
...Lower Colorado River Valley...
Gusty north winds will develop across the region on the backside of
the deepening trough across the southern Rocky Mountains. These
strong winds will yield elevated to locally critical fire-weather
conditions for a few hours during the afternoon.
...Please see www.spc.noaa.gov/fire for graphic product...