852 FXUS63 KDMX 311738 AFDDMX Area Forecast Discussion National Weather Service Des Moines IA 1238 PM CDT Sat May 31 2025 ...Updated for the 18z Aviation Discussion... .KEY MESSAGES... - Temperatures warm into the 80s through the weekend with upper level smoke making for hazy skies. Some may mix down to the surface at times this afternoon into Sunday. - Thunderstorms return to the area Tuesday into early Wednesday. The potential for any severe weather will continue to be monitored over the next few days. && .UPDATE... Issued at 325 AM CDT Sat May 31 2025 Smoke continues to be the main forecast feature through the weekend. Few changes from previous except extended smoke mentions through Sunday with RAP/HRRR smoke guidance in good agreement of smoke remaining aloft through the weekend keeping skies hazy. Lowered high temperatures a few degrees both days as a result, though highs still in the 80s. Some of this smoke may be brought down to the surface this afternoon, especially towards northern Iowa, but may become more widespread by Sunday afternoon. Any smoke that does make it to the surface could lead to a reduction in visibilities at times or the smell of smoke. Any air quality impacts will continue to be evaluated by the Iowa DNR. && .DISCUSSION... Issued at 229 PM CDT Fri May 30 2025 While most of Iowa is cloud free this afternoon, one cannot look up into a blue sky. Smoke from wildfires across Canada has pushed into Iowa today and satellite imagery shows this blanketing a large swath of the midwest. This smoke has remained aloft with no observational sites reporting reductions to visibility that would indicate smoke making it to the ground. HRRR and RAP smoke data continues to indicate that this will last through Saturday as well. There is a chance with a passing shortwave on Saturday that some of this smoke may be pulled down to the surface, and this is indicated with slightly elevated concentrations in both RAP and HRRR surface smoke variables. Any impacts to air quality across Iowa will be monitored by the Iowa DNR. Aside from smoke impacts, the passing shortwave should have little tangible impact to Iowa weather with CAMs keeping the area dry. A stray shower my be possible in the afternoon with marginal instability in some HRRR soundings, however confidence to include this in the forecast at this time is low. Meanwhile, temperatures through the weekend and into Monday will soar through the mid to upper 80s with theta e advection into the area as the thermal ridge shifts east. At the same time, a western US trough will dig across the Rockies with an associated surface low ejecting across the midwest by Monday into Tuesday. Impacts to Iowa look to arrive on Tuesday and this will be the next window for thunderstorms. The current track takes the low across Missouri and lifting into Illinois to Wisconsin. That would keep the more robust impacts to the south, however southern Iowa could see some triple point action as the surface low skims southern Iowa. GFS soundings at Lamoni and Des Moines indicate 1200-1500 J/kg surface based CAPE with 100-200+ m2/s2 0-1 km SRH and nicely curved hodographs through roughly the lowest 3 km. While better deep layer shear lags the instability axis in current model runs, this environment remains more than sufficient for supporting organized convection. We`ll continue to fine tune the forecast in the coming days, but this will likely be the next window for severe storms in Iowa. Another system will pass over the area late this week. && .AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 1230 PM CDT Sat May 31 2025 VFR conditions prevail through the period, with Canadian wildfire smoke being the most notable weather condition this period. Smoke remains in place aloft, although satellite imagery has shown considerable thinning over the last few hours. Therefore, have stuck with only BKN (KFOD and KDSM) or SCT (KMCW, KALO, KOTM) VFR ceilings for all sites through the afternoon. Expect there to be another push of smoke tonight into Sunday, primarily aloft. Confidence is still quite low in whether smoke will reach the surface at any sites during this period, so have continue to leave it out of TAFs. Reduced visibilities and surface smoke look to be more likely farther to our west, but we will continue to monitor for changes in these trends through the day and evening. && .DMX WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...05 DISCUSSION...Hagenhoff AVIATION...Dodson