National Weather Service Forecast Discussion |
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578 FXUS65 KBOU 160917 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 317 AM MDT Tue Jun 16 2026 .KEY MESSAGES... - Warm this week, with heat peaking Wednesday. Portions of the plains could see afternoon highs in the mid to upper 90s. - Elevated fire weather conditions possible each day this week, with widespread critical fire weather conditions likely for the mountains and valleys on Wednesday. - More active weather may return by the weekend. && .DISCUSSION /Through Monday/... Issued at 312 AM MDT Tue Jun 16 2026 The theme for this week is hot, dry, and breezy as an upper level ridge dominates our weather pattern through the weekend. Main concerns are elevated-to-critical fire weather conditions, mainly for the mountains and valleys, and heat risk for the Urban Corridor due to above normal temperatures. On Tuesday the upper level ridge will strengthen over southwestern U.S. with west/northwest winds advecting warm air into the region. Highs will be in the upper 80s to lower 90s for the plains, and between 60s to high 70s across the mountains and valleys. 700-mb flow will increase in the afternoon, leading to gusts up to 30-40 mph across the high terrain and off the Cheyenne Ridge. This will bring elevated to locally critical fire weather conditions for the mountains/valleys (See Fire Weather Discussion below). Wednesday will be another dry, hot, and windy day with increasing concerns for critical fire weather conditions for the mountains and valleys, and heat risk for the urban corridor. Winds aloft will once again strengthen, with 700-mb winds increasing up to 45-55 kts. This will promote downsloping winds and aid in compressional heating across the plains. Temperatures are forecasted to reach up to the mid 90s along the Urban Corridor. Heat Risk is up to 2, which correlates to a moderate risk for those who are sensitive to heat. Given that this will be the warmest day so far, with temperatures expected to be 10+ dg above normal, a heat advisory was considered. However, it looks like we will be just shy of our criteria. In addition, there is some uncertainty with the timing of a cold front on Wednesday (could be anywhere from late afternoon to late evening) which could keep temperatures cooler than forecasted if it arrives early. This is further reflected in some ensemble solutions trending towards cooler maximum temperatures. Regardless, Wednesday will be hot and those sensitive to heat should take precautions. Widespread critical fire weather conditions are expected across the mountains and valleys on Wednesday due to the above normal temperatures, breezy winds and low relative humidity values. Have opted out of expanding the Fire Weather Watch as partners have recently deemed fuels in the foothills and Urban Corridor as not critical. See more details in the Fire Weather Discussion. The aforementioned cold front on Wednesday will bring temperatures closer to seasonal normals on Thursday, with highs in the mid-80s expected. However, this mild reprieve in hot temperatures will be short lived, as the upper level ridge is progged to shift east and the axis of the mid-level thermal ridge situates itself over Colorado. Temperatures will once again rise to the low 90s across the plains on Friday and Saturday. For the weekend, the upper level ridge will somewhat flatten due to an incoming shortwave trough. This will bring cooler temperatures by Sunday and could bring isolated rain/thunderstorm chances, mainly for the plains. Right now, NBM has 25-35% PoPs (slightly higher for the far eastern plains) which seems reasonable at this time. Looking into early next week, slightly above normal temperatures are likely, with lingering moisture possibly providing chances for isolated afternoon convection. && .AVIATION /06Z TAFS through 06Z Wednesday/... Issued at 1119 PM MDT Mon Jun 15 2026 VFR conditions expected through the TAF period. Winds are currently light (214-217-218. && $$ DISCUSSION...MAI AVIATION...MAI FIRE WEATHER...MAI