Area Forecast Discussion
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
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044 FXUS65 KBOU 300830 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 230 AM MDT Thu Jul 30 2026 .KEY MESSAGES... - Isolated showers and thunderstorms this afternoon, with a few strong-to-severe storms possible, mainly for the eastern plains. - Another round of isolated thunderstorms possible Friday afternoon. - Heat returns by the weekend, with temperatures possibly reaching up to 100 F on Sunday and Monday. && .DISCUSSION /Through Wednesday/... Issued at 225 AM MDT Thu Jul 30 2026 Current radar shows ongoing isolated rain showers along the high terrain, with a few of them spilling onto the plains. These showers do have the ability to produce gusty outflow winds, as surface observations have already reported gusts up to 50 mph in the foothills (40 mph around the Boulder area). With the passing of a weak upper level shortwave, additional showers and thunderstorms are possible before sunrise, mainly for the northern mountains, with gusty outflow winds as the main concern. With northwest flow aloft today, our source for monsoon moisture will be cut off. However, isolated showers and thunderstorms are still expected this afternoon. CAMs favor storms forming over the foothills and I-25 corridor and trekking east through the afternoon, where they will tap into better moisture, and thus better instability. Most storms are expected to be marginal, but can`t rule out isolated severe thunderstorms producing 60 mph winds and hail, especially for the eastern plains where SPC has introduced a Marginal Risk (1/5). In addition, with PWs still over an inch, heavy rainfall is possible with strongest storms. However, flash flooding is not much of a concern, given faster storm motions. Overnight Thursday, a weak backdoor front will bring `cooler` temperatures for Friday, with forecasted highs expected to be in the 80s to low 90s. The shortwave embedded in the upper level ridge will bring another round of isolated showers and thunderstorms on Friday. Modeled Skew- T soundings show more favorable shear profiles, but instability seems to be lacking. Denver metro and areas south have been included in a Marginal Risk (1/5) for severe weather, with hail and strong outflow winds as the main concern. Guidance is in good agreement of the upper level ridge restrengthening once again over the weekend, with above normal temperatures returning to the region. Ensemble solutions continue to indicate highs reaching up to 100 both Sunday and Monday for the plains. After that, models begin diverging as multiple upper level shortwaves arrive next week. Depending on the evolution of these disturbances, we could be seeing `cooler` temperatures by Tuesday (unfortunately it would be short lived), with precipitation chances returning by midweek. However, it is too soon to go into the details yet as things could still change. && .AVIATION /06Z TAFS through 06Z Friday/... Issued at 1148 PM MDT Wed Jul 29 2026 VFR conditions likely through the TAF period. Winds are currently drainage at DEN and APA, with light and VRB winds at BJC. Showers are ongoing in the mountains and should continue to weaken as they trek east. However, there is a 10-20% chance that BJC could see a brief light rain shower in the next 2 hours. Due to low confidence, have kept it out of the TAF for now. Guidance continues to hint at fog forming over the plains due to high dew point temperatures. However, with southwest winds expected in the morning, don`t think fog would materialize at the terminals. Light (<10 mph) winds will prevail in the morning for all TAF sites, with winds gradually shifting to a west/northwest flow by mid-morning. Another round of afternoon convection is possible (~30% chance), however storms will be isolated and confidence on exactly where these storms form is low. Kept the PROB30 in the TAF as it is possible that terminals would still see strong outflow winds (30-35 kts) from surrounding convection. Overnight Thursday, a backdoor cold front could make its way around 04Z-07Z. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...MAI AVIATION...MAI