National Weather Service Forecast Discussion |
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157 FXUS65 KBOU 311118 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 518 AM MDT Mon Aug 31 2026 .KEY MESSAGES... - Better precipitation chances today, with another round of afternoon/evening showers and storms, a few may become severe over the plains. - Warmer and drier conditions expected from Tuesday through Friday. && .DISCUSSION /Through Sunday/... Issued at 215 AM MDT Mon Aug 31 2026 SW flow aloft will continue today thru tonight. Water vapor imagery shows one disturbance over nrn CO tonight which will move away from the area this morning. Meanwhile, a secondary disturbance embedded in the flow will move from nern AZ across wrn CO late this aftn/early evening and into WY by late evening/overnight. There will continue to be an influx of monsoon moisture across the area with PW values up to 150% above normal. Thus will see showers/tstms become likely by mid to late aftn over the higher terrain. Across the plains, MLCAPE will be around 1000 j/kg with bulk shear up to 30 kts. Overall, there will be some threat of wet microbursts from the stronger storms along with marginal large hail. Best timing of tstms will be from late aftn thru the mid evening hours. Storms will produce locally heavy rain in some areas but they will be moving along as flow aloft increases this evening. As for highs, readings will be near seasonal normals. On Tue, there will be a lingering chc of showers across the area in the morning hours. By aftn, drier air in SW flow aloft will move into the area which will lead to lower chances for showers/tstms. Highs will remain near seasonal normals. For Wed and Thu, dry air in SW flow aloft will remain over the area with only a low chc for aftn showers/tstms. Temperatures will be warmer as readings rise into the upper 80`s to lower 90s across the plains. By Fri thru next weekend, an upper level high build over the central US as an upper level low resides over the Pacific NW. This will allow for the flow aloft to become more SSW. Models eventually want to advect some monsoon moisture, from the swrn US, into the higher terrain by the weekend. If that happens then there would be an increasing chc for showers/tstms, mainly over the higher terrain. Across the plains, expect above normal temps to continue with just a slight chc of tstms next weekend. && .AVIATION /12Z TAFS through 12Z Tuesday/... Issued at 513 AM MDT Mon Aug 31 2026 Winds were S to SSW early this morning except at BJC which was light and variable. Winds at all three sites should trend to light and variable in the 14z-15z time period. By early aftn winds will become easterly. Showers and tstms will develop after 21z and will linger thru early this evening. Brief gusty winds from 35 to 45 mph will be possible. After 01z still will have lingering showers and possibly a tstm thru 05z with brief wind gusts from 25 to 35 mph. After 05z there will still be some widely sct -shra possible thru 09z so have kept in a prob30. Winds by 01z will be NW and then transition to S/SSW by 05z. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...RPK AVIATION...RPK