Fire Weather Outlook Discussion
Issued by NWS
Issued by NWS
732 FNUS22 KWNS 312002 FWDDY2 Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0302 PM CDT Fri Jul 31 2026 Valid 011200Z - 021200Z ...EXTREMELY CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE COLUMBIA BASIN IN CENTRAL/SOUTHEASTERN WASHINGTON AND NORTHERN OREGON... ...CRITICAL FIRE WEATHER AREA FOR EASTERN OREGON AND FAR WESTERN IDAHO INTO EASTERN WASHINGTON...THE IDAHO PANHANDLE...AND NORTHWESTERN/NORTH-CENTRAL MONTANA... ***Dangerous fire weather conditions are expected across central/southeastern Washington and northern Oregon on Day 2/Saturday.*** ...Day 2/Saturday Update... The Extremely Critical risk area has been expanded into northern Oregon to account for downslope enhanced southwest to westerly surface winds and critically low RH amid a very receptive fuelscape. Ahead of a dry cold front, southwesterly winds will gradually accelerate up to 20 mph as RH begins to decline. Notably, as the cold front passes in the morning/early afternoon hours, a wind shift from southwesterly to broadly westerly (perhaps to west-northwesterly in the evening) is depicted by high-resolution guidance, with sustained winds increasing up to 30 mph. Daytime RH values will range from 5-15% within the risk area; though, should increase to over 50% throughout overnight hours. The orientation of enhanced 850-500 mb winds will gradually become more perpendicular to the Cascades (and eventually the Northern Rockies in the late afternoon) tightening surface pressure gradients, generating a favorable environment for very strong downslope winds. In the lee and immediate foothills of the higher terrain, sustained winds of 30+ mph are possible (gusts over 50 mph). As the trough translates eastward in the afternoon, robust southwesterly flow aloft will overspread the northern Rockies. High resolution guidance depicts a 700 mb 60-70 kt emerging along the Rocky Mountain front of north/central Montana, advancing strong downslope sustained winds of up to 30 mph or greater (50+ mph gusts) starting around 00z and persisting though the overnight hours. RH values will range from 20-30 percent amid 99th annual percentile ERCs and an increasingly receptive fuelscape. These overnight meteorological conditions have led to an expansion in Critical fire weather highlights, though locally extremely critical conditions may be possible. Elevated to locally critical fire weather conditions are likely across the central mountains of Idaho into the Snake River Plain, though recent rainfall across eastern Idaho preclude the expansion of Critical highlights. Hot, dry and windy conditions on Day 2/Saturday will likely serve as a preconditioning-style event, leading into expansive critical fire weather concerns on Day 3/Sunday alongside the emergence of lightning-induced holdovers. See the previous discussion for more information. ..Elizalde-Garcia.. 07/31/2026 .PREV DISCUSSION... /ISSUED 0219 AM CDT Fri Jul 31 2026/ ...Synopsis... Upper-level ridging will remain in place from the Desert Southwest into the northern High Plains on D2/Saturday as a potent upper-level trough moves onshore across the Pacific Northwest and British Columbia. As this occurs, a surface low will amplify across southern Alberta, with a dry cold front progressing rapidly east-southeastward through the Pacific Northwest and Northern Rockies. A tightening surface pressure gradient underlying a 35-45 kt 700 mb jet will promote sustained strong southwesterly to westerly surface winds amid a very dry boundary layer. The best overlap of these conditions is forecast across portions of the Columbia Basin in central and eastern Washington where dry, downslope flow in the lee of the Cascades is expected to promote RH reductions to 15-20% in conjunction with sustained surface winds of 20-30 mph (locally higher in favored terrain/gap flow areas) and gusts of 35-45+ mph. A few large wildfires are already ongoing across this region, and ERCs are noted to be approaching or exceeding the 95th percentile. This combination of meteorological and fuel conditions supports an upgrade to Extremely Critical with this outlook issuance. While the best overlap of the tightening surface pressure gradient and strengthening mid-level winds is forecast across eastern Washington, a broader area of critical fire weather conditions is also expected from eastern Oregon and far western Idaho into eastern Washington, the Idaho Panhandle, and northwestern/north-central Montana. Across this region, sustained surface winds of 20-25 mph are forecast to overlap very low RH of 5-20% (with the lowest RH values forecast across southeastern Oregon and in the lee of the Rockies in north-central Montana) and ERCs commonly above the 90th to 98th percentiles. Recent guidance also suggests that a separate area of stronger, pre-frontal southwesterly surface winds (up to 20 mph) may manifest across portions of eastern Idaho Saturday afternoon, which may support locally critical fire weather concerns. Sustained westerly/southwesterly winds of 15-20 mph, very low RH of 5-20%, and ERCs ranging from the 80th to 98th percentiles will also foster Elevated fire weather concerns across a larger area encompassing much of the northern Great Basin, eastern Pacific Northwest, northern Rockies, and portions of the northern High Plains. ...Please see www.spc.noaa.gov/fire for graphic product... $$