Fire Weather Outlook Discussion
Issued by NWS
FNUS28 KWNS 202126
Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0325 PM CST Fri Jan 20 2017
Valid 221200Z - 281200Z
An active southern-stream will result in several days of potential
fire weather conditions across portions of the southern Plains as a
series of shortwave troughs move through the strong mid/upper level
flow extending across the southern tier of the CONUS.
The first system will likely be moving from the southern Plains into
the lower MS valley at the beginning of the period (12Z Sunday),
continuing eastward through the Southeast while maturing. Shortwave
ridging is expected on D4/Monday in the wake of this system across
the Plains before another shortwave trough ejects out across the
central Plains on D5/Tuesday. As this occurs, another shortwave
trough is expected to drop southward through the western periphery
of the broad troughing covering the western CONUS. Some weakening of
this shortwave trough is likely on D6/Wednesday as it moves eastward
in tandem with its parent upper trough, which is expected to
gradually shift eastward toward the Plains.
...D3/Sunday through D5/Tuesday: Portions of Southern Plains...
A dry and deeply mixed airmass is expected in the wake of the first
shortwave trough across much of the southern Plains on D3/Sunday.
Strong mid/upper level flow amidst this deeply mixed environment
will result in strong northwesterly winds. Sustained wind speeds
from 30 to 35 mph with gusts around 45 mph are anticipated,
particularly across south Texas. Additionally in this region,
downslope effects will contribute to temperatures in the upper 70s.
These warm temperatures amidst an already dry airmass will support
minimum RH values around 20 percent. These meteorological conditions
combined with dry fuels will result in a critical fire weather
threat for south Texas. High temperatures, and related minimum RH
values, decrease farther northwestward (from the Edwards Plateau
into southeast NM), with a resulting decrease in the probability of
critical conditions as well.
A lee trough is expected to deepen across central High Plains on
D4/Monday, with the tightened surface pressure gradient contributing
to breezy conditions across portions of the southern High Plains.
Antecedent dry airmass, characterized by PW values near 0.30", will
support minimum RH values around 20 percent during the afternoon.
Some elevated fire weather conditions are possible but generally
unreceptive fuels should temper the overall threat.
On D5/Tuesday, a strong pressure gradient (resulting from the
development of a deep surface low over the central Plains) and
increasing mid/upper level flow will contribute to gusty conditions
from eastern NM across the TX panhandle/west Texas and into western
OK. Much like D4/Monday, temperatures are again expected to be 10-15
degrees above-average with minimum RH values generally in the 20s.
Some critical fire weather conditions are possible but current
uncertainty regarding fuel receptiveness precludes introducing any
70% delineations with this forecast.
...Please see www.spc.noaa.gov/fire for graphic product...