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571 FXUS65 KBOU 100557 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 1157 PM MDT Thu Apr 9 2026 .KEY MESSAGES... - A brief cool down Friday with scattered rain showers. Isolated thunderstorms will also be possible over the higher terrain and portions of the I-25 Corridor. - Scattered showersSaturday with a few thunderstorms, mainly over the mountains andfar northeast plains. - Warm and dry Sunday and Monday, with breezy/windy conditions possible along with increasing fire conditions. && .DISCUSSION /Through Thursday/... Issued at 1051 PM MDT Thu Apr 9 2026 SW flow aloft will be over the area today with southeast low level flow across the plains. Expect a decent Denver cyclone to develop although not sure exactly where it will be located. Initial thoughts would be to have it over nrn Douglas county. There will be a convergence zone associated with it which may act as a focus for tstm development late in the aftn into the early evening hours. MLCAPE up to 500 j/kg will develop along and south of the boundary in the aftn. If convective temps can be reached then may see a few stronger storms with a weak landspout or two possible along the boundary. Temps will be a problem as readings to the north and west of the Denver cyclone will be cooler than south and southeast of the cyclone. Thus have modified readings to account for this. Over the plains, stratus may hold thru much of the aftn which may keep highs in the upper 40`s to lower 50s. Over the higher terrain will see a chc of aftn showers and tstms. For Sat, SW flow aloft will remain in place. Cross-sections show an increase in moisture over the higher terrain with favorable lapse rates. As a result, will see a good chc of showers and a few tstms. Across the plains, the low level flow will be SSW with best moisture confined to the far nern plains, where SBCAPE may be up to 1000 j/kg. Thus will see a chc of high based showers and a few storms in the aftn, with a few stronger storms, possible over the far nern plains. Highs will be warmer with readings in the 70`s over the plains. By Sun, drier air in SW flow aloft will spread over the area with little chc for pcpn. Temperatures will remain warm across the plains with increasing wind over the higher terrain and portions of the plains. On Mon, an upper level trough will move into the Great Basin with stg SW flow aloft. Meanwhile, sfc low pres will be located across the plains. Overall, it looks like another day of mainly dry weather across the plains with above normal temps and gusty winds. Over the mtns, latest data suggest best chc for showers and a few tstms will be Mon night and not during the aftn. In addition, expect windy conditions as well. By Tue, there is still a lot of disagreement as to the track of an upper level low. The ECMWF has it now moving across WY while the GFS has an open wave trough affecting the area. For now, it appears best chc of precip will be over the mtns with quite a bit of uncertainty across the plains. For mid week, the flow aloft will become more westerly which will lead to a drier pattern along with warmer temperatures. && .AVIATION /06Z TAFS through 06Z Saturday/... Issued at 1157 PM MDT Thu Apr 9 2026 Main concerns surround chance of showers and a couple thunderstorms with variable winds this afternoon, and a low chance of stratus early this Friday morning. A weak front pushed across the airports this evening, and another easterly surge is still possible toward 10Z-12Z Friday. That later surge would have enough cooling and upslope to bring a slight (20%) chance of stratus and MVFR ceilings to KDEN with even smaller chances at KBJC and KAPA. A Denver Convergence Vorticity Zone (DCVZ) is expected to develop, and the exact location will determine how winds evolve through the day. At this time, we have fairly high confidence (70%) that the cyclone will be developing and moving south of KDEN which means Easterly winds should develop and hold through most of the day, before becoming NW or VRB once convection develops in the area. That cyclone and associated convergence will also be the main driver of convective initiation, but appears to be a rather late day with most shower/storm development holding off til 22Z-01Z. We`ll keep the TEMPO -TSRA in the forecast for that period of highest confidence, and also mention VRB gusts to 25-30kts. Convective activity is mostly agreed upon to move east and exit the area by 02Z. Then winds should settle down and return to fairly normal south/southwest winds by 04-07Z Saturday as the DCVZ breaks down. && .FIRE WEATHER... Issued at 1051 PM MDT Thu Apr 9 2026 Elevated to critical fire conditions will return to the plains, higher valleys and foothills Sunday into Monday. Gusty southwest winds will occur in some areas along with low humidity levels. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...RPK AVIATION...20 FIRE WEATHER...RPK