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449 FXUS65 KBOU 172310 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 410 PM MST Wed Dec 17 2025 .KEY MESSAGES... - Strong downslope winds impacting foothills and I-25 corridor will end this evening. Widespread wind gusts of 60-80 mph and localized gusts up to 90 mph are possible. A cold front will bring northwest winds gusting 50-60 mph across the northern plains this evening. - Strong winds will continue to impact the mountains this evening through tomorrow morning, with gusts up to 80-90 mph expected at times. - Banded snowfall and strong winds will lead to treacherous travel conditions in the mountains this afternoon and evening. - Strong winds and periods of high fire danger will return Friday, with questions remaining regarding the spatial extent of the strongest winds. - Mountain snowfall looks to return for Saturday. && .DISCUSSION /Through Wednesday/... Issued at 350 PM MST Wed Dec 17 2025 Winds are currently peaking across the Front Range and lower foothills, with multiple reports of 80+ mph wind gusts. Hi-res guidance continues to indicate strong winds continuing for the next couple of hours for the lower elevations before backing up into the mountains again this evening. We are still on track to let the High Wind Warning expire for the lower foothills this evening, and let the High Wind Warning for the mountains to continue through tomorrow morning. While there will be brief lulls in strong winds along the mountains overnight, generally expect gusts up to 80 mph at times, with a gradual weakening through Thursday late morning/early afternoon. For the plains, gusty winds will continue through early this evening. Then, a cold front is progged to enter the northern plains by 6/7 PM and quickly sweep south. QG fields show deep subsidence over the plains, which will likely help bring down strong winds to the surface. Gusts up to 60 mph are possible, particularly off the Cheyenne Ridge. However, short-range guidance has continued to indicate the strong winds reaching all the way down to Washington county, so have included them in the warning. After midnight, northwest winds weaken below high wind criteria. However, expect gusty winds up to 40-50 mph to continue through the morning hours Thursday. Critical fire weather concerns are expected to continue this afternoon despite marginal relative humidity values. Strong winds along the foothills and adjacent plains will promote rapid fire spread, should a fire occur. However, as winds weaken this evening along the foothills, conditions will improve to let the Red Flag Warning expire. In addition, even with the strong winds expected with the cold front, slightly higher relative humidity values and cooler temperatures will keep fire weather concerns at bay. The Winter Weather Advisory will continue through tonight. Current radar imagery shows snow showers ongoing for the northern mountains, with minimal accumulations so far. However, with guidance indicating strengthening frontogenesis across the higher terrain, banded snow is possible, with snowfall rates reaching 1"/hr to briefly 2"/hr. Total snow accumulations of 3-8" is still on track, with localized higher amounts of 10" possible near ridgetops. Strong winds will cause blowing snow along high passes, which will greatly reduce visiblities. Now for tomorrow. In general, cool temperatures and gusty winds are expected for the entire forecast area. However, the primary concern for strong winds will be across the northeastern plains in the morning. The core of the upper level jet streak is still progged to be overhead Thursday morning, with the 700-mb flow reaching up to 70-80 kts. Modeled soundings indicate steep lapse rates at the same time, which will help mix strong winds down to the surface. In addition, hi-res guidance has continued to show gusts reaching, or barely exceeding, high wind criteria. For this reason, have opted to upgrade Sedgwick and Phillips counties to a High Wind Warning tomorrow, with gusts up to 55-65 mph possible. Elevated to critical fire weather conditions are possible, particularly over the eastern plains (see Fire Weather Discussion). Another mountain wave and high wind event is expected along the front range and foothills late Thursday into Friday. Models are showing cross barrier flow around 70 to 100kts at ridge top. There is a robust pressure gradient shown in the Sangster, with MSL differences around 13 to 14mb between GJT and DEN. Models are hinting at a weak inversion around 600mb in the afternoon and showing some inverse shear in mid levels (80kts to ~50kts higher up). The relatively weak nature of these ingredients lower confidence a bit in the winds making it down towards the I-25 corridor. But, as we saw with the current event, this can definitely change as we get closer to the event. Right now, we have very high confidence in strong winds impacting the higher elevations of the front range, with lowering confidence of really strong winds the further east we go. A High Wind Watch will be in effect late Thursday through late Friday for the mountains and Friday afternoon for zones 38 and 39. The strong winds and dry conditions will lead to fire weather concerns as well (see Fire Weather Discussion). Weak QG subsidence Friday afternoon will transition to weak ascent in the evening as the left exit region of the upper level jet approaches. The approach of the jet will help bring an end to the high wind event and trigger some snow showers in the mountains. The best chance for snow this weekend will be overnight Friday into early Saturday afternoon, with lower chances (036. High Wind Watch from Thursday evening through Friday afternoon for COZ033>036. Red Flag Warning until 6 PM MST this evening for COZ238>243-245- 246. High Wind Warning until 7 PM MST this evening for COZ038-039. Fire Weather Watch from Friday morning through Friday evening for COZ238>240. High Wind Watch from Friday morning through Friday afternoon for COZ038-039. High Wind Warning until midnight MST tonight for COZ042-044-048- 049. High Wind Warning from 5 AM to noon MST Thursday for COZ050-051. && $$ DISCUSSION...MAI/AP AVIATION...Danielson FIRE WEATHER...MAI/AP