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534 FXUS65 KBOU 191842 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 1242 PM MDT Wed Aug 19 2026 .KEY MESSAGES... - Isolated to scattered storms into the evening, with a couple severe storms still possible mainly Palmer Divide area into southern Lincoln County. - Summer heat and drier Thursday into Friday, although isolated showers/storms in the mountains. - Monsoon moisture returns this weekend and holds into early next week, with increasing chance of storms. && .DISCUSSION /Through Wednesday/... Issued at 1242 PM MDT Wed Aug 19 2026 Main concern in the short term is development and strength of convection this afternoon into early evening. We are seeing drying in the mid and upper levels spread southward across the forecast area, but low level moisture is hanging on across the plains. Best MLCAPE is developing pretty much as expected over the Palmer Divide through Lincoln County, where MLCAPE has grown to 1000-1500 J/kg. Farther north, the drying will limit overall MLCAPE to just a few hundred J/kg. Thus, the main threat of any severe weather would be from the crest of the Palmer Divide through central/ southern Lincoln County through early evening. Farther north, mainly isolated and less intense storms are expected as there is still some weak support/instability along and south of the upper level jet axis. Convection is expected to end latest over the far southern portion of our forecast area by mid to late evening, with clearing skies and temperatures a few degrees above normal overnight. Thursday and Friday will feature very warm and mostly dry weather as the upper level ridge starts to amplify and a drier northwest flow aloft holds over the forecast area. The amplification of the ridge will support a return of full summer heat, with highs pushing into the lower to mid 90s across all of the plains and I-25 Corridor on Thursday. Friday will see even further warming, with mid to upper 90s well agreed upon by guidance. Looking into this weekend, ensembles were still in good agreement that monsoonal moisture arrives as the upper level ridge migrates ever so slowly eastward. That would put the forecast area in southwest flow aloft and increased moisture advection. Precipitable water (PW) values climb to around 150% of normal on average. That will support scattered to numerous storm coverage in the mountains each day, at least once the ridge axis shifts slightly eastward - which should be by Sunday at the latest. That`s when a shortwave moves over the northern U.S./Canada border area, leading to a little more westerly component aloft. That component would also aid an increase in showers/storms drifting eastward onto the plains. That same relative weather pattern holds through early next week, which supports daily chances of showers and storms along with slightly cooler (but still above normal) temperatures. A couple weak backdoor fronts are possible during this period, which means a day or two should see highs settle back into the mid to upper 80s across the plains and I-25 Corridor. && .AVIATION /18Z TAFS through 18Z Thursday/... Issued at 1200 PM MDT Wed Aug 19 2026 Winds are currently light (