Fire Weather Outlook Discussion
Issued by NWS
Issued by NWS
379 FNUS21 KWNS 071639 FWDDY1 Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1138 AM CDT Mon Sep 07 2026 Valid 071700Z - 081200Z Morning satellite imagery portrays thunderstorms across the Dakotas and a very dry airmass trailing an eastward progressing cold front currently in central Wyoming. 16z surface observations exhibit 15-25 mph sustained west-southwesterly winds and gusts up to 40 mph in the Wyoming plains. In the wake of a departing surface low, dry and breezy conditions will continue to permeate the northern Plains this afternoon. Despite spotty accumulating rainfall over the last 12-24 hours in far eastern Wyoming and southwestern South Dakota, ERCs broadly remain at the 80-95th percentile, maintaining an Elevated fire weather threat across the region. Only minor adjustments were made to the outlook area to exclude less-receptive fuels; see the previous discussion for more information. ..Elizalde-Garcia.. 09/07/2026 .PREV DISCUSSION... /ISSUED 0148 AM CDT Mon Sep 07 2026/ ...Synopsis... Strong southwesterly flow aloft will overspread the northern Plains today as an mid-level shortwave trough traverses northeastward across the northern Rockies and into south-central Canada. Simultaneously, a surface cyclone currently analyzed in southeastern Montana will strengthen as it lifts northeastward into the southern Canadian Prairies, resulting in a tightened surface pressure gradient across the region. While slightly cooler daytime temperatures will prevail, windy conditions spurred by the strengthening pressure gradient will foster elevated fire weather concerns across portions of the northern/eastern Wyoming, southern Montana, and the Black Hills vicinity. ...Southern Montana into northern/eastern Wyoming and the Black Hills vicinity... The aforementioned strengthening surface pressure gradient will encourage sustained surface winds to strengthen to 15-25 mph across the northern High Plains. An overlapping 30-40 kt 700 mb jet will also translate eastward through the afternoon, with deep boundary layer mixing encouraging 30-40 mph wind gusts to reach the surface (perhaps up to 50 mph in terrain favored areas and along exposed areas of higher elevation). While minimum RH values are only forecast in the 15-25% range, fuels across the area are commonly above the 80-90th percentiles. This overlap of strong surface winds, modest minimum RH, and receptive fuels will support an elevated fire weather threat across the region today. While widespread critical conditions appear unlikely at this time owing to only modest RH reductions, locally critical conditions may be possible should lower minimum RH values materialize. Of further note, a trailing cold front will extend southwestward from the strengthening surface low. The passage of this front through the region will yield a shift from generally westerly winds to northwesterly. While some uncertainty remains regarding the exact timing of the frontal passage, current guidance suggests the front will extend southwestward from near the MT/ND/SD border by 18 UTC, with the shift to northwesterly winds gradually spreading farther southeastward after 00 UTC Tuesday as the front begins to accelerate; although, wind speeds should largely weaken by around 03-06 UTC. ...Please see www.spc.noaa.gov/fire for graphic product... $$