418 FXUS63 KDMX 060552 AFDDMX Area Forecast Discussion National Weather Service Des Moines IA 1252 AM CDT Sat Jun 6 2026 ...Updated for the 06z Aviation Discussion... .KEY MESSAGES... - A lull in the storm activity for much of today, but storms return this evening and tonight, mainly across southern and central Iowa. There are renewed concerns for flash flooding and severe storms with all hazards possible. - Much of Saturday will be dry but muggy, with scattered late day and evening storms again possible across central and southern Iowa. - Heavy rain is a concern for renewed showers and thunderstorms on Sunday into Monday. Then heat builds next week with many areas exceeding 90 degrees. && .SHORT TERM /THROUGH SUNDAY/... Issued at 1214 PM CDT Fri Jun 5 2026 Upper air pattern early this afternoon features a low amplitude upper trough moving through the northern Plains and upper Midwest. Still seeing rather thick cloud cover across much of Iowa due to abundant low level moisture (enhanced by yesterday’s rainfall) trapped under the developing inversion. The storms from overnight pushed the effective sfc boundary into Missouri this morning, but the latest sfc obs show winds shifting back southerly across portions of southern and central Iowa. Some breaks in the cloud cover have allowed temps to climb into the 70s, and expect some additional heating the remainder of the afternoon. With the expected high temperatures (upper 70s to lower 80s) model soundings continue to show at least a weak cap /MLCIN of -25 J/kg/ remaining over much of the CWA through early evening. With generally weak background forcing/ascent, any CI will likely be tied to moisture convergence along the sfc boundary. Several of the CAMs /HRRR, RRFS/ try to initiate isolated storms across far southern Iowa from 22-00Z. While very conditional, if any storms can initiate in that region, strong MLCAPE /2000-3000 J/kg/, steeper mid-level lapse rates, and effective deep layer shear values of 25-35kts could lead to supercell development. Large hail and damaging winds would be the primary threat, although an isolated tornado is possible, especially near any locally backed flow and enhanced SRH near the boundary. The more robust severe threat will occur later in the evening and then continue into the overnight as stronger lift develops due to the strengthening nocturnal LLJ. Good model consensus shows storms developing over ern NE/swrn IA from 9-11pm CDT and then expanding eastward along the sfc boundary. Highest threat for storms will generally occur along and south of I-80, but will be ultimately dependent on where the sfc boundary ends up. Even during these overnight hours, favorable MUCAPE/effective shear will continue at least an isolated severe weather threat /mainly hail and wind/ along with an escalating heavy rain threat, see Hydro Discussion below. Storms will likely persist until around sunrise Saturday before gradually weakening. See the SPC Day 1 Slight Risk (Level 2 of 5) and any forthcoming SWOMCDs for further details. Saturday and Saturday Night.. Any remaining storms will be diminishing on early Saturday morning. Shortwave upper ridging is then expected to develop by Sat afternoon, with broad subsidence and little in the way of forcing noted. As such, still expecting much of Saturday to be dry, warm, and muggy, with highs again in the 80s. The deterministic models and CAMs do indicate the possibility for isolated/scattered late afternoon or evening storms, potentially along any sfc or residual outflow boundaries. The most likely location of storms is again across central and southern Iowa, where the strong instability will reside, MLCAPE of 2000-3000 J/kg. Wind shear in that same area remains generally weak /less than 20 kts/ so mainly pulse or perhaps multicell storms being the most likely mode, with marginally severe hail or wet microbursts possible. A SPC Day 2 Marginal Risk (Level 1 of 5) appears reasonable for now. Any storms will be diurnally driven, with activity waning after sunset. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Issued at 1214 PM CDT Fri Jun 5 2026 An upper level cutoff low across the southern plains on Sunday morning will lift into the midwest by the afternoon and evening. Deep moisture transport out of the gulf increases into Iowa, especially southern Iowa. Scattered daytime showers and thunderstorms may linger with renewed thunderstorms developing in the evening and continuing overnight into Monday morning as the upper low/trough tracks across Iowa. The threat for severe storms appears low at this time with deeply saturated soundings exhibiting very little instability (500 J/kg) or shear (20 kts or less). The primary concern this period will be additional heavy rain across southern Iowa, following heavy rain Thursday and Friday nights. With PWATs near 2” and deep warm cloud layers exceeding 4000m, expect efficient rain fall across southern into central Iowa. The upcoming week should be mainly dry, though few weak waves skimming the area could bring renewed showers or thunderstorms to the area. Heat builds through the week as the thermal ridge expands and shifts into the midwest. While NBM guidance has rockets up into the mid to upper 90s by the middle to end of next week, this seems overdone from over mixing and with weak waves thwarting the highest temperatures. NBM has been on the highest end of the guidance envelope the past several cycles and will continue to need nudging down unless the pattern changes. Despite the overzealous NBM, temperatures will still be quite warm and reach the upper 80s to low 90s. The next more organized chance for precipitation arrives late in the week around Thursday. && .AVIATION /06Z TAFS THROUGH 06Z SUNDAY/... Issued at 1251 AM CDT Sat Jun 6 2026 Thunderstorms are ongoing across southern Iowa and may briefly impact KDSM and KOTM as the night goes on. Across northern terminals, patchy fog will develop bringing the potential for MVFR VIS through sunrise. After sunrise, VFR conditions are expected at all terminals through the remainder of the TAF period. && .DMX WATCHES/WARNINGS/ADVISORIES... Flood Watch until 7 AM CDT this morning for IAZ070>075-081>086- 092>097. && $$ SHORT TERM...05 LONG TERM...Fowle AVIATION...Rotter