National Weather Service Forecast Discussion |
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638 FXUS65 KBOU 112016 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 216 PM MDT Fri Sep 11 2026 .KEY MESSAGES... - Very warm today with only isolated high based showers/virga late this afternoon and evening. - Slight increase in shower/storm coverage this weekend. Cooler Saturday, then warmer Sunday. - Unsettled pattern next week, with multiple cold fronts expected to bring a few more noticeable cooldowns. && .DISCUSSION /Through Friday/... Issued at 1245 PM MDT Fri Sep 11 2026 This morning`s wave cloud kept some heat relief in place for the northern corridor for the first half of the day. Now that the cloud has dissipated, temperatures are quickly heating, with KLMO seeing an eight degree warming in the past hour alone. Temperatures were adjusted slightly to account for the cooler morning, but we are still expecting a hot day across the lower elevations due to downsloping winds and a slight warming in temperatures aloft. Water vapor imagery shows moisture has slightly increased in the westerly flow aloft through the morning. We still expect some isolated high-based showers to develop this afternoon over the higher elevations, with some virga showers expected to bring gusty outflows to the lower elevations. We may manage to squeeze a few sprinkles out of some of them, but mostly just expect 30-40 mph winds as virga passes over for areas east of the mountains. A cold front is expected late tonight/early Saturday morning that will bring some gusty northerly winds across the plains and cooler temperatures for Saturday. A slight increase in moisture is expected with the front as well. Afternoon showers and a few storms will be possible, with the best chances being over the northern mountains where instability will be greatest, but can`t rule out some holding together long enough to push off the higher elevations. Have added a mention of at least slight chance for PoPs to the forecast across the northern plains and areas along the Palmer Divide. Sunday is still on track to be the hottest day of the week in between cold fronts. While the NBM seems to have a warm bias, most guidance does show afternoon highs in the low to mid 90s, so afternoon highs were trimmed back slightly to be more in line with the majority of guidance. Either way, it will still be hot for the second week of September. There will be some better instability in place across the northeast plains that if tapped into, could allow for some stronger to severe storms in the afternoon/evening. Not much has changed in the long term forecast today, with the northern tier still expected to remain active over the next week. A few cold fronts are still progged to bring a few more cooldowns through the week, and afternoon showers and storms will be possible each afternoon. && .AVIATION /18Z TAFS through 18Z Saturday/... Issued at 1206 PM MDT Fri Sep 11 2026 VFR expected through the TAF period. Winds over the region are currently light (