FXUS63 KDMX 271924 AFDDMX Area Forecast Discussion National Weather Service Des Moines IA 224 PM CDT Tue May 27 2025 .KEY MESSAGES... - On and off rain showers gradually shift eastward through the rest of today. - A period of dry conditions Wednesday morning, then showers and storms possible in the afternoon to evening. Low potential for a few funnel clouds north. - On and off showers remain Thursday, then generally dry Friday through the weekend with gradual warming. && .DISCUSSION... Issued at 224 PM CDT Tue May 27 2025 Rainy conditions continue primarily across the northwest half of the state today as scattered on and off showers pass overhead this afternoon, thanks to the slow passage of a rather large upper level low pressure slowly tracking east/southeast over the Upper Midwest. Rainfall totals so far have generally remained around 0.10-0.25 inches west of I-35, though pockets of accumulations up to 0.50-0.75 inches fell over far western Iowa up to roughly 1pm. On and off isolated showers however been occurring into central Iowa as well, with rain accumulations so far below 0.25 inches. Cooler temperatures also are noted across the majority of the state, with values in the upper 50s to mid 60s, while some clearing over southeast Iowa has allowed for warmer temperatures in the upper 60s to low 70s. As for the rest of today, CAM guidance overall progresses the current scattered showers gradually eastward in slow progression through the rest of the afternoon to evening, so have increased PoPs at least slightly across the eastern portion of the service area to account for that. Widespread cloud cover will limit any significant cooling overnight into Wednesday, with lows falling into the upper 40s west to mid 50s east. The aforementioned system is still slated to slide into Iowa Wednesday, becoming centered overhead, with rain chances remaining over at least eastern Iowa early on. Otherwise, a small window of drying conditions per short-term guidance is expected across much of the state by mid-morning, before chances (30-50%) for additional spotty showers return across at least the northern and eastern portions of the state Wednesday afternoon to evening. During this drying period, areas of clearing are signaled per HRRR and NAM guidance over much of the area, which in turn will allow for low level instability increasing around 200-300 J/kg with an increase in stretching potential primarily into northern Iowa by the afternoon to evening. These conditions, along with low LCLs around 500-700m over northern Iowa setting up as low clouds settle back in therefore keeps the potential of a non-zero chance for some funnel cloud development Wednesday afternoon to evening. Any thunderstorms that do develop however remain quite unlikely to become severe, hence the remaining general thunder coverage highlighted across Iowa per the Storm Prediction Center. By Thursday, this upper level low looks to break off the main parent circulation and track eastward out of the region, which is suggested to result in the development of another upper level low dropping into Iowa. An uptick in forcing for lift south and east into Missouri/Illinois will result in more appreciable rainfall as the signal remains for more of a MCS to move across that area in the morning, though the majority of Iowa generally remains dry through the morning. However, light shower chances (20-40%) return once again, becoming scattered by the late morning through at least the early evening before drying. A few weak storms may occur over southern Iowa during this time frame as well given the return of at least some instability and lift over the area. Dry conditions become widespread Friday as a mid-level ridge over the western CONUS gradually shifts into the Midwest. Warmer weather will come with this ridge as highs are expected to reach into the upper 70s to low 80s. A weak shortwave riding the larger scale flow Saturday remains in the long term guidance as it drops out of the Dakotas into Nebraska/Iowa, bringing at least a low potential for returning showers Saturday. Differences are noted between the GFS and Euro in terms of rainfall coverage, with the GFS keeping rainfall chances mainly over eastern Iowa, while the Euro covers the state with more widespread QPF. Given this information, would generally lean towards keeping the more blanketed mentions (<20%) of PoPs across the eastern CWA Saturday, with overall little impact as rainfall totals look to remain under a tenth of an inch. Warmer weather settles in Sunday into early next week as a large thermal ridge passes over the Central Plains. High temperatures will generally range in the low to mid 80s through next week Tuesday, with lows in the 60s. && .AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 1238 PM CDT Tue May 27 2025 Scattered showers remain across largely the northwest half of the state this afternoon, and will continue throughout the next several hours as showers gradually shift eastward. Mid-level clouds are expected for the rest of the day and into early Thursday which will keep VFR conditions, before low clouds lead to MVFR conditions after 06z. Winds will remain light out of the north to northeast throughout the period. && .DMX WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Bury AVIATION...Bury