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026 FXUS65 KBOU 070543 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 1143 PM MDT Sat Jun 6 2026 .KEY MESSAGES... - Widespread critical fire weather conditions expected in fuel- prone areas by Tuesday and Wednesday. - Hottest temperatures Sunday, and then again Tuesday and potentially Wednesday. Highs generally in the mid 90s across the I-25 Corridor and plains, but near 100 possible over the northeast plains Tuesday. - Brief respite in the heat Monday, and then increasing heat relief late next week. && .DISCUSSION /Through Saturday/... Issued at 251 PM MDT Sat Jun 6 2026 Current water vapor imagery shows Colorado is currently sitting between an upper-level low over TX/OK and an upper-level low entering the Pacific Northwest this morning, placing Colorado on the western side of an upper-level ridge. The main weather concerns for today will be with developing critical fire weather conditions across portions of the plains, and with gusty outflows from high- based showers/storms. Things have taken a little longer to dry out over the northeast plains after early morning fog, but relative humidities are already moving towards the teens and winds are simultaneously increasing. Today`s Red Flag Warning will continue until 7 PM this evening when RH values are expected to increase to above critical thresholds (More on fire weather in discussion below). High temperatures are expected to be in the 90s across the plains, and 70s to 80s in the mountain valleys. We are already seeing convection form along the higher elevations early this afternoon, with a boundary stretching from the Palmer Divide northward across Douglas County and towards DIA that has kicked up a few showers that are producing some gusty microbursts but little precip. This is expected to be the outcome from most showers that develop this afternoon as ACARS soundings show large dewpoint depressions already in place, and forecast soundings show inverted-v profiles (DALR up to 500mb), that would limit chances for most precip to reach the surface. Hi-res guidance has persisted in showing shower coverage expand this evening generally south and east of the Denver area, so have increased PoPs to account for this potential, with the greatest precip chances expected along and just north of the Palmer Divide. We are expecting gusty outflows from these with potential for some gusts to 50 mph. For Sunday, hot temperatures are expected once again, but winds are expected to slacken a bit across the lower elevations that would limit any critical fire weather conditions from developing. The approaching upper-level low over the Pacific Northwest is expected to move eastward and into the Northern Rockies through the day and lee troughing is expected to deepen as a response. This will enhance compressional warming and we should see temps a few degrees warmer than today`s. There should be enough mid-level moisture present to see some afternoon showers, with the best chances for the northeastern plains. Monday will bring a slight cooldown, with afternoon highs expected to drop back into the 80s for the urban corridor. A surface trough is expected to increase low-level moisture and there will be enough instability in place to allow for some afternoon convection. Forecast soundings indicate enough MUCAPE (1200-1600 J/kg) and shear (EBWD >30 kts) from increasing southwesterly flow aloft in place for isolated strong to severe storms to develop, mainly for areas east of I-25. Tuesday and Wednesday are still on track to be hot, dry, and windy, with critical fire weather conditions expected under well-above normal temps. See Fire Discussion below for more details. Winds are expected to increase with a strengthening pressure gradient both aloft and at the surface. There are still some uncertainties with the timing of an upper-level trough over the Northern Rockies, but this will be the deciding factor on just how hot temperatures get on both Wednesday and Thursday, as an associated cold front is expected to drop south into Colorado. Latest guidance is trending towards the faster trough ejection, which would move the hotter temps to the east a little sooner, with near-normal temps expected to end the week. && .AVIATION /06Z TAFS through 06Z Monday/... Issued at 1142 PM MDT Sat Jun 6 2026 Strong and gusty southerly winds were finally relaxing as of 0530Z, and will continue to diminish through 08Z with normal S-SW winds then expected through 15Z. Winds may become VRB for a few hours 15Z-21Z, although a trend to W-NW still expected with peak heating and some mixing. However, that`s only about a 50-60% chance since strong diurnal heating and resultant upslope will offset the mixing component. What is more concerning is potential for virga and thus VRB G35+ kt microburst winds. DCAPE is advertised to be at least 1400 J/kg and still just enough moisture to produce virga from about 17-18K ft MSL. Thus, we opted for Prob30 to message that gust potential, most likely 20Z-24Z. && .FIRE WEATHER... Issued at 251 PM MDT Sat Jun 6 2026 A Red Flag Warning will remain in place until 7 PM this evening across portions of the plains for low RH, gusty winds, and dry lightning potential. Winds are expected to gradually increase through the afternoon from east to west across the plains, with gusts between 25-35 mph. Additional gusty winds will be possible through the evening from outflows associated with showers/storms (up to 50 mph possible). For Sunday, we are expecting elevated fire weather conditions to develop across the plains as RH values are forecast to drop into the single digits to low teens in the afternoon. Winds are expected to remain below critical thresholds for the majority of the plains, but we are expecting winds to increase for our higher mountains and valleys where fuels have yet to reach critical dryness. No fire highlights are anticipated for Sunday. We are still anticipating minimal fire weather concerns on Monday as we see increased moisture and cooler temperatures, but things will ramp up for the rest of the forecast period as winds are expected to increase ahead of an approaching upper-level trough amidst near record-high temperatures. HDWI still continues to show Tuesday likely reaching above the 95th percentile and above the 90th for Wednesday. These are expected to be the two most critical days for the majority of the forecast area as the forecast has RH ranging from 8% to 12% (Tues) across all of the plains with widespread 30-40 mph gusts, and 10-15% RH (Wed) with another day of 30-40 mph gusts expected. There are still some uncertainties on Thursday`s outcome with the timing of the approaching trough, but critical fire weather conditions may persist, though there should be some improvements to both RH and winds for Thursday, and the HDWI does have the majority of its members dropping us down to the below the 75th percentile. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...9 AVIATION...20 FIRE WEATHER...9