Clearpost.online It's your post, so post it!

Day 1 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
1155 AM CDT Wed Sep 07 2022

Valid 071700Z - 081200Z

...EXTREMELY CRITICAL FIRE WEATHER AREA FOR NORTH-CENTRAL MONTANA...
...CRITICAL FIRE WEATHER AREA FOR SOUTHEASTERN OREGON AND
VICINITY...
...CRITICAL FIRE WEATHER AREA FOR PARTS OF WESTERN AND CENTRAL
MONTANA...
...CRITICAL FIRE WEATHER AREA FOR SCATTERED DRY THUNDERSTORMS IN
EAST-CENTRAL OREGON...CENTRAL IDAHO...SOUTHWEST MONTANA...

The ongoing forecast remains on track with minimal changes to the
isolated dry thunder area based on observations. A multi-faceted and
high-impact fire weather day is still expected across the Northwest
into the northern Great Basin and northern Rockies. In the short
term, thunderstorm activity is most likely to occur from central
into east-central Oregon as a weak disturbance moves north and east.
Greater storm coverage can be expected as heating occurs through the
afternoon and mid-level ascent increases late afternoon into the
evening. Sustained winds and strong gusts will also increase across
north-central Montana later today as the boundary layer deepens
substantially. See the previous forecast for more details.

..Wendt.. 09/07/2022

.PREV DISCUSSION... /ISSUED 0104 AM CDT Wed Sep 07 2022/

...Synopsis...
A strong pattern shift is forecast across much of the western CONUS
today and tonight as the prominent ridge of high pressure is broken
down by a strengthening Pacific trough. Unseasonably strong winds
aloft along with increasing forcing for ascent will overspread the
Pacific Northwest and Northern Rockies, while a cold front sweeps
out of southern Canada. Ahead of the front, an unstable atmosphere
along with very warm temperatures and strong winds will support
weather conditions favorable for dry thunderstorms as well as
extreme fire behavior. 

...Northern Rockies and adjacent plains...
Across portions of northern ID and MT, westerly winds are forecast
to increase early this morning and through much of the day ahead of
the approaching cold front. Enhanced by strong surface pressure
gradients from the deepening lee low across the southern Canadian
Rockies, west-southwest surface winds of 25-35 mph are likely by
early afternoon. Deep vertical mixing to 600 mb evident on regional
model soundings also shows potential for stronger surface gusts
(40-50+ mph) as 50-65 kt of flow aloft approaches. Coincident with
peak heating, the well-mixed boundary layer, very warm surface
temperatures, and downsloping westerly flow will support low teens
to single digit RH values. The co*bination of hot, dry and windy
conditions within very dry fuels lends high confidence to widespread
critical and extremely critical fire weather conditions across
portions of northern and central MT. 

Extreme fire weather conditions should continue through the
afternoon ahead of the fast-moving cold front arriving after dark.
While cooler temperatures and increasing humidity will acco*pany the
frontal passage, a rapid wind direction change to northerly flow is
also expected. Fire weather concerns may linger for a few hours
overnight before winds gradually decrease and surface humidity
recovers. 

...Dry Thunderstorms...
Ahead of the cold front, dynamic ascent and modest mid-level
moisture associated with the approaching upper trough will support
isolated to scattered thunderstorms from northern CA, through
portions of the northern Great Basin, into the northern Rockies.
Forecast sounding show generally 0.5 to 0.75 in PWAT values with
100-500 J/kg of MUCAPE. Below the unstable layers, high LCLs (2-3 km
AGL) and with fast storm motions will favor poor precipitation
efficiency and the potential for strong outflow winds over much of
the West. Recent fire activity indicates that fuels remain highly
receptive across the region and will support critical
lightning-driven fire weather concerns.

Storm coverage is expected to be greatest along the cold front from
portions of eastern OR, central ID, into western MT. hr** lightning
probabilities show high confidence in the potential for scattered
strike coverage atop highly receptive fuels in this area.
Additionally, the risk for convective outflow gusts greater than 60
mph also suggests a high probability of critical fire weather
concerns across this region given the expected storm potential. A
Scattered dry thunderstorm area was introduced, and additional
information related to the severe weather risk is available in the
Day1 Convective Outlook. 

...Cascades and northern Great Basin...
Across the Cascades and Great Basin westerly flow will remain strong
in the wake of the cold front farther east. Bolstered by increasing
flow aloft from the upper trough, widespread 15-25 mph surface winds
are expected along with low humidity. Widespread elevated fire
weather conditions are expected within dry fuels. Critical fire
weather conditions will also be possible across portions of the
northern Great Basin across southern OR, and far northern CA/NV.
Here, higher confidence in winds greater than 25 mph exists along
with afternoon humidity values below 15%.

...Please see www.spc.noaa.gov/fire for graphic product...