|
U.S. & Canada 00-UTC 48 Hour Surface Smoke Forecast
Map is in operation from early April through October 31
U.S. Day 1 Fire Weather Outlook
ZCZC SPCFWDDY1 ALL
FNUS21 KWNS 221632
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1132 AM CDT Sat Aug 22 2026
Valid 221700Z - 231200Z
...CRITICAL FIRE WEATHER AREA FOR MUCH OF NORTHERN
WASHINGTON...NORTHERN IDAHO PANHANDLE AND FAR NORTHWESTERN
MONTANA...
...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF
SOUTH-CENTRAL/SOUTHEAST WASHINGTON AND FAR NORTH-CENTRAL OREGON...
...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF NORTHEAST
CALIFORNIA...NORTHWEST NEVADA...AND SOUTH-CENTRAL/SOUTHEAST
OREGON...
...Dry Thunderstorms - Northern Intermountain West and northern
Rockies...
Current radar and satellite imagery depict scattered showers and
thunderstorms across eastern OR into central WA, as a robust
upper-level trough invades the Pacific Northwest. Precipitation
efficiency has been limited with very few surface observation sites
showing meaningful rainfall due to fast northward/northeastward
trajectories of the high-based showers/thunderstorms. Latest CAM
ensemble guidance and forecast soundings continue to depict a
lingering, dry sub-cloud layer across eastern WA, northeastern OR
and the ID Panhandle through the evening and overnight hours. The
arrival of a 50+ knot 500 mb jet and associated increasing shear and
forcing for ascent will likely aid in nocturnal convection atop this
residual dry boundary layer. Despite increasing Pacific moisture
leading to PWAT values in the 0.8-1.1" range across this region,
storm motions upwards of 40 mph will limit rainfall amounts over a
receptive fuelscape, increasing lightning ignition potential. Thus,
scattered dry thunderstorm highlights were extended eastward farther
into northwest MT and likewise southward into far southeastern WA
and ID Panhandle where greater convective coverage is expected.
...Dry/Windy Conditions - Northern/Central Intermountain West...
Only minor eastward expansion of existing critical and elevated
highlights were needed across portions of the northern Great Basin
into central ID based on latest model guidance consensus and current
surface observation trends.
..Williams.. 08/22/2026
.PREV DISCUSSION... /ISSUED 0200 AM CDT Sat Aug 22 2026/
...Synopsis...
Along the northwestern periphery of an expansive upper ridge
centered on the central/southern Rockies, a robust midlevel trough
and accompanying south-southwesterly jet streak will overspread the
Northwest through the period.
...Dry Thunderstorms - Northern Intermountain West and northern
Rockies...
The 00Z observed soundings across parts of the central Great Basin
show ample midlevel moisture, which will continue spreading
northward across the northern Intermountain West and northern
Rockies today. Diurnal heating/boundary-layer mixing beneath the
moist plume will yield a broad area of weak instability by this
afternoon -- characterized by inverted-V thermodynamic profiles. As
midlevel height falls/forcing for ascent preceding the midlevel
trough overspread this instability, isolated to scattered
fast-moving thunderstorms will track northward across the region
this afternoon and evening.
The greatest coverage of high-based storms is expected across parts
of northern WA into the northern ID Panhandle, where forcing for
ascent will be strongest. While a mix of wet/dry storms is possible,
the fast storm motions and dry boundary layer should limit rainfall
amounts. Given very receptive fuels, the risk of lightning-induced
ignitions will be maximized here. Additionally, enhanced deep-layer
wind shear related to the upper-level jet will promote some
strong-severe storm clusters, capable of producing severe wind gusts
and hail. See the SPC Day 1 Convective Outlook for more details on
the severe risk.
...Dry/Windy Conditions - Northern/Central Intermountain West...
The strong deep-layer south-southwesterly flow accompanying the
midlevel trough will result in strong downslope flow off the
Cascades and northern Sierra. This will result in a broad area of
15-20 percent afternoon RH and 15-25 mph sustained
west-southwesterly surface winds. The strongest winds are expected
within terrain-favored areas, such as the Columbia Basin and in the
lee of the southern Cascades -- where dry/receptive fuels will
support critical fire-weather conditions during the afternoon.
|
U.S. Day 2 Fire Weather Outlook
ZCZC SPCFWDDY2 ALL
FNUS22 KWNS 221953
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0253 PM CDT Sat Aug 22 2026
Valid 231200Z - 241200Z
...Southern Plains...
A subtle embedded mid-level short wave will enter the Southern
Plains on D2/Sunday, aiding in isolated shower and thunderstorm
development by Sunday afternoon. A dry boundary layer with large
surface dew point depressions as temperatures climb into the lower
100s F will promote evaporation of high-based thunderstorm rain
cores over the northern TX Panhandle, OK Panhandle and far western
OK. Isolated dry thunderstorm highlights have been introduced into
the aforementioned area as fuels remain extremely dry and receptive.
Additionally, a slight westward expansion of existing elevated
highlights across the Southern High Plains was made based on latest
forecast guidance and dry fuel conditions.
...Northern Rockies into Central Montana...
Model guidance trends has depicted a faster progressing mid-level
trough through the Northwestern U.S. through Sunday. With this
accelerated trough advancement, forcing for ascent has been shifted
primarily into far northeastern WA and the ID Panhandle for Sunday
as the mid-level jet enters the Northern Rockies. A slight pullback
for isolated dry thunderstorm highlights was made across
north-central WA. A broader dry thunderstorm threat remains over
central MT Sunday, followed by dry and breezy conditions and
elevated fire weather concerns later in the day as drier westerly
flow filters into the region.
..Williams.. 08/22/2026
.PREV DISCUSSION... /ISSUED 0201 AM CDT Sat Aug 22 2026/
...Synopsis...
A midlevel trough will continue eastward across the Northwest and
northern Rockies during the day -- where ample midlevel moisture
will remain in place atop a diurnally deepening boundary layer.
Related forcing for ascent preceding the trough will promote
isolated to widely scattered fast-moving thunderstorms across parts
of the northern Rockies and Northwest during the afternoon and early
evening. Given 0.7-0.9 inch PW, a dry/well-mixed boundary layer, and
fast storm motions, a mix of wet/dry thunderstorms will pose a risk
of lightning-induced ignitions and gusty/erratic outflow winds atop
receptive fuels. Additionally, enhanced deep-layer
west-southwesterly flow accompanying the midlevel trough will
overspread the warm/dry air mass in place across the northern
Rockies, yielding dry/breezy (elevated) fire-weather conditions
during the afternoon.
Farther south, dry/breezy southerly return flow will develop across
parts of the southern High Plains -- in response to a passing
low-amplitude midlevel trough. These dry/breezy conditions atop
increasingly receptive fuels will favor elevated fire-weather
conditions during the afternoon.
U.S. Day 3-8 Fire Weather Outlook
ZCZC SPCFWDD38 ALL
FNUS28 KWNS 222158
Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0458 PM CDT Sat Aug 22 2026
Valid 241200Z - 301200Z
...Synopsis...
Broad high pressure will remain over the Southwestern U.S. while a
mid-level trough arcs eastward, over the northern periphery of the
emergent upper-ridge, reaching the Upper Midwest by the middle of
next week. A weak mid-level perturbation embedded within overall
southwesterly flow could bring some isolated convection to portions
of the northern Great Basin on Day 3/Monday. Another upper trough
impinges upon the Pacific Northwest Days 4-6/Tuesday-Thursday,
bringing additional fire weather concerns in the form of breezy and
dry conditions to the Columbia Basin and northern Great Basin. This
trough along with modest mid-level moisture in place across the
northern Rockies could bring a dry thunderstorm threat back into
parts of ID and western MT on Day 5/Wednesday.
...Day 3/Monday...
...Northern Great Basin...
A subtle mid-level wave within southwesterly flow aloft and
lingering monsoon moisture should promote isolated afternoon
convection across the northwestern Great Basin on Day 3/Monday.
Isolated high-based thunderstorms are possible over dry fuels where
ERC values in the 90-95th percentile remain. A 10 percent dry
thunderstorm risk area persists over southeastern OR, southwestern
ID and northern NV.
...Southern Plains...
West to southwest winds of 10-20 mph, high temperatures in the lower
100s F and afternoon RH reductions of 15-20 percent south of a
frontal boundary should evolve over portions of northwestern TX and
far southwestern OK on Day 3/Monday. This hot, dry and breezy
environment combined with extremely dry fuels will likely bring
elevated fire weather concerns to the area. The northern extent of
the existing 40 percent critical probability area was removed owing
to expected farther south positioning of the frontal boundary.
...Day 4-6/Tuesday-Thursday...
Fire weather concerns will increase across the northwestern U.S. as
the next upper-level trough begins to impact the region. Dry and
breezy conditions are likely to emerge east of the Cascades across
northeastern CA, southeastern OR and adjacent NV on Day
4-6/Tuesday-Thursday under dry southwesterly flow and in the
Columbia Basin beginning on Day 5/Wednesday. High-based
thunderstorms are also expected across the northern Rockies where
sufficient but limited moisture aloft (PWATs in the 0.6-0.9" range),
fast shower/thunderstorm motions and dry fuels will support new
ignitions. A broad 10 percent dry thunderstorm risk area was
introduced for portions of central ID and ID Panhandle into western
MT. Dry and breezy conditions are maintained through Day 6/Thursday,
perhaps of greater magnitude, east of the Cascades and northern
Great Basin as the upper trough and associated stronger mid-level
flow moves solidly into the region. 40% critical probabilities were
initially introduced for this threat but expansion and/or upgrade to
70 percent probabilities could occur for future outlooks.
..Williams.. 08/22/2026
|
