Area Forecast Discussion
Issued by NWS Des Moines, IA
Issued by NWS Des Moines, IA
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755 FXUS63 KDMX 011953 AFDDMX Area Forecast Discussion National Weather Service Des Moines IA 253 PM CDT Mon Jun 1 2026 .KEY MESSAGES... - Isolated showers and thunderstorms possible (20 to 30%) this afternoon over western Iowa. A stronger storm could produce gusty winds, small hail and locally heavy rainfall. - Drier conditions develop Tuesday through the day Wednesday. Highs in the low 80s with breezy winds over western and northwestern Iowa. - Pattern turns more active through the second half of the weak, with multiple rounds of rain and thunderstorms possible into the weekend. && .SHORT TERM /THROUGH WEDNESDAY/... Issued at 250 PM CDT Mon Jun 1 2026 Sunny skies and dry conditions have graced most of the state today, although one rogue storm in northern Iowa did spoil the nice day for those in Emmet and Palo Alto counties, producing gusty winds and over an inch of rain as it passed through. Fortunately, this storm has since dissipated, leaving mostly clear skies and pleasant conditions over all of central Iowa. Scattered cumulus has started to develop as the boundary layer mixes out and atmosphere begins to destabilize today. The vertical profiles over Iowa are fairly dry, but a subtle shortwave passing through Nebraska will try to pull better mid-level moisture into western Iowa this afternoon. This same area will boast 2000 to 3000 J/kg of MLCAPE and modest mid-level lapse rates. The overall forcing with this wave is weak, but higher resolution guidance does indicate some subtle convergence in the low levels. These factors may be just enough for a few isolated showers or storms to develop as we reach peak heating this afternoon, mainly over western Iowa. If storms do manage to take off, the respectable amount of instability in place could lead to some stronger updrafts. The steep low level lapse rates and downdraft CAPE of 1000+ J/kg will also be conducive for gusty winds as storms precipitate into the dry layer below. However, the 0 to 6 km wind shear will be marginal (20 to 30 kts) and updrafts may struggle to organize and maintain themselves. Therefore, prolonged severe storms are not anticipated, but a few stronger storms could still produce strong winds or small hail. Likewise, some very localized heavy rainfall could occur with these storms, as storm motions will be extremely slow, which could lead to a quick inch or so of rain. The afternoon activity should generally diminish into the evening as the shortwave weakens and a Great Lakes high begins to push into and establish itself over Iowa. Model guidance does still try to produce an MCS over the plains to our west overnight, but this activity gets stopped in it`s tracks along the Iowa/Nebraska border where it meets the dry air mass advecting in from the east. This surface high will linger through Tuesday and Wednesday, keeping the low and mid level moisture streams to the west of our forecast area and central Iowa dry through the middle of the week. Conditions over the state will be fairly pleasant through this period, with highs in the low 80s and periods of sunshine. With western Iowa being more on the edge of the surface high, tighter pressure gradients and proximity to the better moisture stream will lead to breezier conditions and more cloud cover than areas farther east, but overall should still remain dry through the day Wednesday. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... Issued at 250 PM CDT Mon Jun 1 2026 Wednesday night and through the second half of the week will see a slight change in the pattern, as the eastern US long-wave trough departs eastward and the surface high follows along with it. Return flow on the backside of the departing high will advect warm moist air up into the state, meeting with another shortwave trough along the US/Canada border Wednesday night into Thursday. This will bring the return of shower and thunderstorm chances to Iowa, mainly over northwest into northern Iowa, although rain could develop throughout the area as theta-e advection increases ahead of the wave. This Wednesday night into Thursday rain will kick off a more active pattern through the end of the week, as we transition to more of a zonal flow pattern with multiple shortwave passages into the weekend. Instability will also be increasing through the end of the week, as the warmer and higher dewpoint air works up into the state. It`s a bit too early to dig too far into the severe weather potential, but Friday looks like it has the greatest potential for a few strong storms, albeit limited by low wind shear values. Machine learning probabilities are keying on Friday as well, putting a 5 to 15% probability for severe storms (equivalent to a marginal risk from SPC) on Friday. Of similar concern will be the potential for multiple days of rainfall Wednesday night through Saturday, some of which could be rather efficient as the better moisture stream and PWATs pivot westward into Iowa. This could be some much needed rainfall, provided it doesn`t all fall in one spot. Potential severe weather and hydro concerns will continue to be evaluated in the coming days. Warm, summer-like conditions persist through the weekend and into early next week. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1219 PM CDT Mon Jun 1 2026 VFR conditions prevail today, with calm to light winds today. Wind direction will be variable today, then prevailing generally out of the east this afternoon and evening. A few scattered showers and storms may develop over western Iowa this afternoon, but aren`t expected to impact terminals at this time. && .DMX WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Dodson LONG TERM...Dodson AVIATION...Dodson