Fire Weather Outlook
— Day 1
Synopsis
Along the northwestern periphery of an expansive upper ridge over the West, a midlevel trough will advance eastward across BC and the Northwest during the day. Within the base of the trough, strong midlevel southwesterly flow will overspread WA, OR, northern CA, and northwest NV. Associated downslope flow in the lee of the Cascades and northern Sierra will aid in deep boundary-layer mixing into the strengthening flow aloft. This will yield a broad area of 15 mph sustained west-southwesterly surface winds (with higher gusts) amid 10-15 percent RH. Locally stronger surface winds can be expected in terrain-favored/gap-flow areas through the Cascades. Given dry/receptive fuels across region, elevated fire-weather conditions are expected.
Farther east, lee troughing over the northern High Plains will promote 10-15 mph sustained easterly surface winds across parts of southeastern WY during the afternoon. These winds, combined with 15-20 percent RH and dry fuels, will favor elevated fire-weather conditions.
000 FNUS21 KWNS 180551 FWDDY1 Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1250 AM CDT Sat Jul 18 2026 Valid 181200Z - 191200Z ...Synopsis... Along the northwestern periphery of an expansive upper ridge over the West, a midlevel trough will advance eastward across BC and the Northwest during the day. Within the base of the trough, strong midlevel southwesterly flow will overspread WA, OR, northern CA, and northwest NV. Associated downslope flow in the lee of the Cascades and northern Sierra will aid in deep boundary-layer mixing into the strengthening flow aloft. This will yield a broad area of 15 mph sustained west-southwesterly surface winds (with higher gusts) amid 10-15 percent RH. Locally stronger surface winds can be expected in terrain-favored/gap-flow areas through the Cascades. Given dry/receptive fuels across region, elevated fire-weather conditions are expected. Farther east, lee troughing over the northern High Plains will promote 10-15 mph sustained easterly surface winds across parts of southeastern WY during the afternoon. These winds, combined with 15-20 percent RH and dry fuels, will favor elevated fire-weather conditions. ..Weinman.. 07/18/2026 ...Please see www.spc.noaa.gov/fire for graphic product... $$