FNUS21 KWNS 201548 FWDDY1 Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1048 AM CDT Sat Jun 20 2026 Valid 201700Z - 211200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE NORTHEASTERN GREAT BASIN FOR SCATTERED DRY THUNDERSTORMS... ...CRITICAL FIRE WEATHER AREA FOR PARTS OF THE EASTERN GREAT BASIN INTO THE FOUR CORNERS FOR DRY AND WINDY CONDITIONS... The existing Isolated Dry Thunderstorm area was trimmed slightly along it's northern boundary to account for ongoing showers with accumulating precipitation and persistent cloud cover this morning. This activity, over east-central OR and far western ID, will stifle chances for dry thunderstorm re-development later today as indicated in the latest forecast guidance and will also limit fuel receptivity. Across portions of this same area, this accumulating precipitation may also prevent afternoon RHs from dipping low enough to meet Elevated wind/RH criteria. However, the latest forecast guidance still maintains Elevated criteria (with RHs dipping below 20%) will be met this afternoon over much of the drawn area. Farther south over the rest of the Great Basin, Southwest, and neighboring areas, the forecast remains on track. Northern portions of the Scattered Dry Thunderstorm area did receive transitory precipitation this morning, but it is not expected to have a significant impact unlike the longer duration showers over areas farther northwest. ..Stearns.. 06/20/2026 .PREV DISCUSSION... /ISSUED 0147 AM CDT Sat Jun 20 2026/ ...Synopsis... Zonal mid-level flow will overspread the CONUS today, with multiple embedded impulses poised to traverse the zonal flow from the Pacific Northwest to the mid-Mississippi Valley. At least one pronounced mid-level impulse will overspread the Great Basin during the afternoon hours, encouraging surface troughing over the Interior West, resulting in dry/windy conditions over the Great Basin toward the Four Corners region. Strong westerly mid-level flow behind the mid-level impulse will overspread the Cascades, supporting dry/breezy conditions over and to the lee of the higher terrain. Finally, deep-layer ascent and enough mid-level moisture (hence buoyancy) accompanying the passing mid-level impulse will encourage high-based thunderstorm development from northern California to western Wyoming. The combination of these meteorological scenarios will support widespread wildfire ignition and/or growth concerns across much of the Intermountain West today. ...Eastern Great Basin to the Four Corners region... By afternoon peak heating, the aforementioned surface lee troughing will support widespread southwesterly surface winds in the 15-25 mph range amid 5-15 percent RH. Widespread Elevated highlights have been continued, with Critical highlights in place where guidance shows the highest likelihood of 20+ mph winds and 5-10 percent RH overlapping for several hours. Across both Elevated and Critical highlights, ERCs should easily exceed the 80th percentile, and thus would support wildfire spread. ...Along and to the lee of the Cascades... Strong flow westerly flow along the higher terrain, along with downslope flow to the lee of the Cascades, will result in 15-25 mph sustained westerly surface winds coinciding with RH as low as 15 percent in spots. Stronger surface winds and lower RH may occur in localized, terrain favoring areas. Either way, the aforementioned ambient surface conditions and dry fuels warrant Elevated highlights. ...Far northern California to far western Wyoming... During the afternoon, diurnal heating, upper support, and orographic lift will all support at least isolated thunderstorm development amid precipitable water values around 0.75 inches. Given dry fuels and potentially light rainfall accumulations with some of the storm cores, a few cells may be associatedwith efficient lightning-induced ignitions given cloud-to-ground strikes, warranting isolated dry thunderstorm highlights. Across northeastern portions of the Great Basin, storms closer to stronger mid-level flow may move faster, potentially supporting a regionally greater lightning-ignition rate given dry fuels and a lesser chance for rainfall accumulations. As such, scattered dry thunderstorm highlights have been continued. ...Please see www.spc.noaa.gov/fire for graphic product... $$