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597 FXUS65 KBOU 071126 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 526 AM MDT Sun Jun 7 2026 .KEY MESSAGES... - More heat ahead, with the hottest temperatures today and then again Tuesday. Highs generally in the mid 90s across the I-25 Corridor and plains, but near 100 possible over the northeast plains Tuesday. - Widespread critical fire weather conditions expected (>80% confidence) in fuel-prone areas by Tuesday, potentially (60% chance) lasting into Wednesday. - Brief respite in the heat Monday, but that also brings a risk of severe storms. - More substantial heat relief expected by Thursday. && .DISCUSSION /Through Saturday/... Issued at 248 AM MDT Sun Jun 7 2026 The upper level low over the Southern Plains states will lift north-northeast today, with the flow across Colorado becoming more southwesterly as the ridge axis over us this morning shifts slowly east. That means a deeper and drier downslope component developing at least along the Front Range. Meanwhile, a developing lee trough will push slowly east across the plains. With the increased downslope component, we should be able to add on a degree or two to yesterday`s highs despite the slightest cool advection noted aloft. Thus, look for highs mostly in the lower to mid 90s across most of the plains. With regard to convection, there is still plenty of low level moisture and modest instability (MLCAPE near 1000 J/kg) east of the lee trough. This could still be enough despite limited shear for an isolated stronger storm or two across the eastern plains (generally along/east of a Sterling to Akron line) late this afternoon through tonight. Otherwise mostly dry conditions can be expected with mostly virga or just a few sprinkles, but those too could produce strong, gusty outflow winds with deep inverted-v profiles past 500 mb. A weak backdoor cold front will push across the plains late tonight, bringing temperatures down a few degrees for Monday with highs mostly in the upper 80s for the plains and I-25 Corridor. At the same time, low level moisture will return to most of the plains. That means more instability and MLCAPE growing to 1000-2000 J/kg over the northeast plains. We`re uncertain how far west the richer airmass makes it, but there is some potential to get close to the I-25 Corridor. We expect isolated to scattered storms develop in the afternoon and intensify as they move eastward into the more unstable airmass. Given increasing shear profiles and available CAPE, supercells will be favored and be capable of producing very large hail, along with a high wind threat and even a brief tornado possible as storms begin to encounter better low level inflow. SPC has outlooked areas north and east of Denver as a Slight Risk and this looks appropriate. For Tuesday, we`ll shift back quickly to a much drier and windier environment, leading to a significant jump in fire weather concerns - see more in the Fire Weather section below. Southwest flow aloft increases considerably as the low and mid level gradients strengthen in between a deep trough moving across the Pacific Northwest/Northern Rockies and a ridge building over the Southern Plains. The resultant lee trough is expected to push farther east in this setup, likely clearing most if not all of the northeast plains by late in the day. With warm advection, strong downslope, and less moisture, Tuesday is shaping up to be the hottest day of the year so far, with mid 90s expected for all of the I-25 Corridor and potentially 100F in the lower elevations of the northeast plains as long as the lee trough passes by. Wednesday is expected to be a transition day with slight cooling aloft, but still potentially breezy conditions due to strength of the upper level flow and low level gradients. Highs should still surpass (>70% confidence) 90F over most of the plains. We`re still on track for cooler weather by Thursday per all the latest data, but the deterministic forecast still lies on the warmer side of guidance. Highs could struggle to reach 80F across the plains if the latest guidance verifies. What was interesting to see was the bump in temperatures for Friday, but there is still more confidence that we cool off again next weekend into early the following week as we see northwesterly flow aloft develop. This should eventually lead to a better chance of showers after mostly dry weather Tuesday through Friday. && .AVIATION /12Z TAFS through 12Z Monday/... Issued at 525 AM MDT Sun Jun 7 2026 We`ll start this period with fairly normal S-SW winds 8-14 kts through about 14Z, then winds should become VRB for a few hours 15Z-21Z. The chance of persistent W-NW winds 18Z-22Z is becoming less certain (30-40% chance) as strong diurnal heating and resultant upslope will offset the mixing component. What is more concerning is what seems to be increasing potential for virga and thus VRB G35+ kt microburst winds. We are expected to warm dry adiabatically through about 17-18K ft MSL, and resultant DCAPE is advertised to be at least 1400 J/kg. Mesoscale models including the HRRR are showing greater potential now for those microburst winds from virga/sprinkles. We still kept the Prob30 to message that gust potential, most likely 20Z-24Z. However, given latest trends would not be surprised if TEMPO VRB G30+ kts needed for a couple hours this afternoon. For tonight, it appears winds will become mainly light and VRB thanks to a weak gradient but some lingering clouds, and then a weak front closer to or shortly after midnight. That front should support a propensity for winds to go more northerly, and opted for an average light NW 07Z-15Z, before a more easterly wind component is expected to develop 15Z-18Z Monday. && .FIRE WEATHER... Issued at 525 AM MDT Sun Jun 7 2026 Hot weather and a drier airmass in all but the far eastern plains today will result in a drop in humidity readings, with some single digit RHs along the I-25 Corridor. Winds will be lighter across the plains, however. In contrast, breezy conditions will develop in the mountains and high mountain valleys, but fuels have yet to reach critical dryness. Thus, no fire highlights are anticipated. Monday will feature a bump in humidity readings especially across the plains, while mountains and mountain valleys remain dry and breezy especially during the afternoon hours. Widespread critical fire weather conditions are still expected Tuesday, depending on local fuel status. Widespread wind gusts of 30-40 mph can be expected by afternoon with humidity readings likely dropping into the 6-12% range in elevations below 9500 feet. HDWI still continues to show Tuesday likely reaching the 90th-95th percentile or greater, but slightly lower probabilities for Wednesday as just slight cooling and a possible decrease in winds occurs. However, it will still be very dry and warm, so critical conditions may very well persist through Wednesday. Forecast Energy Release Component (ERC) for many stations are approaching historical highs (data since 2005) for this time of year. There is now more certainty regarding cooler temperatures by Thursday, but not much recovery in humidity. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...20 AVIATION...20 FIRE WEATHER...20