National Weather Service Forecast Discussion |
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860 FXUS65 KBOU 120837 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 237 AM MDT Sun Jul 12 2026 .KEY MESSAGES... - Prolonged period of hot weather through the week ahead. - Only hints of monsoon moisture reaching the high country by late in the week or next weekend. - Prolonged hot and dry conditions will bring fire weather concerns although we`ll likely stay just shy of Red Flag criteria most days. && .DISCUSSION /Through Saturday/... Issued at 136 AM MDT Sun Jul 12 2026 The forecast pattern has not changed significantly at any point in the last few days, and we look well on track for an extended period of above normal to record high temperatures across the I-25 corridor and high country through the upcoming week. The center of an expansive upper level ridge is now somewhere over Wyoming, and the ridge is expected to continue strengthening today while drifting off to the north and east. Like yesterday, we`ll be on the edge/gradient of the mid-level thermal ridge, with the warmest 700mb temperatures off to the west of our CWA. With little change in the overall synoptic pattern, today`s highs look like they`ll end up pretty similar to what we saw on Saturday... with upper 80s to low 90s across North Park/Middle Park, mid to upper 90s for most of the urban corridor, and upper 80s to mid 90s across the plains. Though there is some modest surface/boundary layer moisture across the plains due to the southeasterly surface flow, forecast soundings yield meager MLCAPE values... with no real mechanism for any convection. There may be a couple of showers across South Park and the surrounding higher terrain, but moisture/instability is much more limited there. The hot/dry pattern is expected to continue on Monday, with highs potentially a degree or two warmer than today. Combined with mild overnight low temperatures, Heat Risk values are a little closer to the "Significant" category... it`s possible a Heat Advisory will be needed for Monday/Monday night across the urban corridor. The ridge across the northern CONUS will be slow to break down through the week, and record high temperatures are likely to continue across the higher elevations... which will remain closer to the thermal ridge axis. Our deterministic forecast still calls for daily, if not all time record high temperatures for many of the longer term climate sites across Jackson/Grand/Summit counties from Tuesday through Thursday. Meanwhile, given the continued hot and dry conditions and a gradual increase in the easterly surface flow, we could start to see elevated to critical fire weather conditions develop around the same time. At this point there`s rather high uncertainty regarding how much overlap in gusty winds and critical relative humidity across any given zone, but Fire Weather Watches may be needed later in the week, mainly across the higher elevations. As we get towards next weekend, moisture associated with the monsoon will slowly start to work its way towards our forecast area. Guidance continues to be a bit slower with the eastward push due to unfavorable positioning of the ridge. Guidance has consistently shown better PWs arriving sometime around Day 6 or Day 7... but until we see this finally start advancing forward, it`s difficult to have too much confidence. On the more optimistic side, there is still a strong ensemble signal that once this moisture arrives, it should stick around. && .AVIATION /06Z TAFS through 06Z Monday/... Issued at 1132 PM MDT Sat Jul 11 2026 VFR conditions are expected through the TAF period. Drainage winds are expected through the overnight hours, before weakening during the morning hours... eventually settling on an east or southeast direction for most of the afternoon. Winds should then turn back towards drainage flow Sunday evening, with some gustier winds possible during the evening and early overnight hours. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Hiris AVIATION...Hiris