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868 FXUS65 KBOU 262010 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 210 PM MDT Tue May 26 2026 .KEY MESSAGES... - Today will bring windy conditions to the plains and potential for elevated fire weather conditions in areas that see little/no rain this afternoon. - Higher terrain will see a few rounds of fast moving showers and thunderstorms this afternoon and evening. There is a marginal threat of flooding mainly over the East Troublesome burn scar. - Wednesday appears to be the most active day with more widespread showers and thunderstorm coverage with locally heavy rainfall possible due to slow movement of thunderstorms. - After somewhat of a lull Thursday, thunderstorm potential will increase again Friday through the weekend with a chance of severe thunderstorms over the plains. && .DISCUSSION /Through Tuesday/... Issued at 202 PM MDT Tue May 26 2026 Current water vapor satellite imagery shows a shortwave trough in southwestern U.S. embedded in the flow of an upper level closed lower over the coast of California. Southerly flow aloft over Colorado has allowed mid-level moisture to be advected into the region, with showers now initiating over the mountains. Expect showers and thunderstorms to increase in coverage over the high terrain this afternoon. Modeled Skew-T soundings show a highly saturated environment, with PWAT values between 0.40" and 0.60". With modest instability over the high terrain, some stronger storms could produce heavy rain. However, given the expected fast storm motion, concerns are minimal for flooding at this time, unless we get training. Across the plains, surface observations have shown southeast winds gusting between 30-40 mph this morning. With current ACARs soundings showing relatively steep lapse rates, expect these gusty winds to persist as daytime mixing continues. Overall lack of decent instability across the plains will limit chances for widespread precipitation to occur this afternoon. However, hi-res guidance does indicate potential for a few showers and isolated thunderstorms for the Palmer Divide and I-25 Corridor late afternoon and evening. With DCAPE values projected to reach up to 800-1000 J/kg, gusty outflow winds will be the main threat. The next few days will likely see a blocking pattern set up across the U.S. with the upper level closed low situated over the western U.S. and blocking high over the Great Plains. This will leave Colorado under relatively weak flow aloft between these two features. On Wednesday, global and regional guidance are in good agreement of the aforementioned shortwave trough slowly trekking across the forecast area, providing synoptic lift for a round of showers and thunderstorms for the plains and mountains. Sounding guidance has continued to indicate a warm moist vertical profile, with PWAT values above the 90th percentile. And, given weak flow aloft, storm motion will be slow as evident in hodographs. Thus, localized heavy rain will be the main concern for tomorrow. However, there is also a conditional threat for a landspout to occur if we get a DCVZ and enough sunshine for low-level instability to build. There is still some question if we can get a Denver cyclone to form tomorrow morning, and with the expected incoming cloud cover we might not get enough instability that some models suggest. Showers may continue into the overnight hours of Wednesday night, before gradually ending by sunrise on Thursday morning. Temperatures should rise to the upper 70s across the plains as the upper level shortwave exits the region. With upsloping, we could have another round of showers and thunderstorms mainly for the Front Range mountains and foothills. Given continued weak flow aloft, storms will be slow moving and thus localized heavy rain is possible again. By Friday and into the weekend, ensemble guidance indicates the upper level low over western U.S. weakening and getting absorbed by the flow of the upper level ridge. With continued southeast flow at the surface, low-level moisture will be continuously advected into the region. Soundings show better instability building over the plains, with mid-level flow turning more south/southwesterly resulting in better shear profiles. This will allow better potential for strong to severe storms Friday and particularly Saturday afternoon. Weak southwest flow aloft will dominate the flow pattern Sunday and into the beginning of the week, with an upper level ridge still in place over Central U.S. With low and mid-level moisture still in place, guidance does indicate potential for continued showers and isolated thunderstorms for the forecast area. However, given overall weak flow and forcing, severe threat is very low at this time. && .AVIATION /18Z TAFS through 18Z Wednesday/... Issued at 1144 AM MDT Tue May 26 2026 Enhanced southerly to southeasterly winds are in place at KDEN/KAPA with light and VRB winds remaining at KBJC late this morning. Expecting winds at KBJC to become more in line with the southeasterlies in the next hour or two. After that, winds should maintain a southerly component through the TAF period for all TAF sites outside of potential for some gusty VRB winds associated with passing showers/storms this evening. The bulk of this potential still remains between the 1Z to 5Z time frame, with the best chances for -TSRA at KAPA and KBJC and -SHRA for KDEN, though there is still a nonzero chance that things hold together long enough coming off the higher terrain to mention a 10-15% chance for -TSRA at KDEN as well. While the bulk of shower and thunderstorm potential will remain anchored to the higher elevations today, we may see some outflows turn winds to the south or west at KDEN this evening where a VRB15G28KT in the current TAF may be adjusted to more of a southwest component to account for this in the coming AMD. Moisture is expected to increase for Wednesday, with higher confidence in thunderstorms impacting all TAF sites compared to today. Expecting CIG to lower by early Wednesday morning to around 5,000`AGL by 12Z, with showers developing from south to north and the likelihood for thunderstorms increasing after 18Z, with the best chances after 21Z. Could see CIG drop as low as 015-020 AGL in the late afternoon and into the evening. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...MAI AVIATION...9