Note: Fire weather probabilistic information in
PDF. Note: On February 23, 2021 the Probabilistic Day 3-8 Fire Weather Outlooks became operational. Please see the Service Change Notice 20-115 for more details.
ZCZC SPCFWDD38 ALL
FNUS28 KWNS 092049
Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0349 PM CDT Fri Apr 09 2021
Valid 111200Z - 171200Z
A split-flow regime in the mid levels will begin with northwesterly
flow dominating much of the western CONUS in the wake of a strong
upper low across the central US. A shortwave trough embedded within
the flow will drive a cold front south across the central Plains
Day4/Monday, before a second upper low across the West Coast digs
into the Great Basin by mid week. Elevated/critical fire weather
conditions are expected periodically across portions of the Great
Basin and Southwest.
...Great Basin into the Southwest...
Ahead of the cold front Day3/Sunday, widespread dry and windy
conditions are forecast from the Four Corners into eastern New
Mexico. Northwesterly flow aloft on the backside of the central US
trough will encourage westerly boundary-layer flow of 15-20 mph. The
modified continental airmass should support humidity of 10-20% which
will be more than sufficient for elevated fire weather conditions
given cured fuels and ongoing drought.
A brief break from active weather conditions is expected late
Day3/Sunday through Day4/ Monday as a cold front swings south
through eastern New Mexico toward the Mexican border. Locally
elevated fire weather conditions may exist with strong winds behind
the front, though widespread conditions appear unlikely at this time
due to cooler temperatures and higher RH.
Lee cyclogenesis ahead of the next West Coast trough is expected to
begin across the Great Basin late Day4/Monday into Day5/Tuesday. The
increasing southwesterly flow aloft and surface pressure falls
should support widespread winds of 15-25 mph. Surface RH should fall
to near critical along a wide swath from the southern Great Basin,
the Four Corners, and into central New Mexico. The GFS remains drier
and stronger with the low-level flow (a well known bias) suggesting
the potential for more widespread critical conditions. A 40%
probability of critical area will be maintained for now.
...Central High Plains...
Periodic downslope flow and a localized risk for elevated fire
weather conditions is expected behind the southward moving cold
front Day4/Monday. The dry nature of westerly low-level flow
supporting RH of 20-30% and surface winds of 20-30 mph will support
locally elevated fire weather conditions given the ongoing drought
and pre-green up dry fuels. Widespread precipitation from the
ejecting Great Basin low/trough should keep the threat confined to
Day4/Monday before cooler and wetter conditions prevail through the
rest of the extended.
Dry down-valley winds across central and southern California
associated with the southern Great Basin low may support elevated
fire weather potential through the day. Surface Rh of 10-20% and
adequate fuels would be sufficient for locally elevated conditions,
though the longevity of the stronger flow and attendant fire weather
threat remains uncertain.
...Please see www.spc.noaa.gov/fire for graphic product...
CLICK TO GET FNUS38 KWNS PFWF38 FIRE WEATHER OUTLOOK DAY 3-8 AREAL OUTLINE PRODUCT