textproduct: Des Moines

KEY MESSAGES

- Showers continue through this morning. Severe thunderstorms in central to eastern Iowa this afternoon. All severe hazards are possible.

- Severe storms Friday afternoon and evening in southern half of Iowa with a Enhanced Risk (level 3 of 5) for severe storms. All severe hazards are possible.

- Cooler and quite this weekend, could become active again later next week.

SHORT TERM /THROUGH FRIDAY NIGHT/

Issued at 309 AM CDT Thu Apr 2 2026

Surface low pressure sits across western Kansas early this morning broad lift across Iowa and the 850 mb LLJ nosing up into southern Iowa. This has allowed for widespread showers to persist through the overnight along with a few embedded rumbles of thunder. That LLJ will increase to 50-60+ kts and push into Iowa through this morning, helping to maintain showers across the area, ending west to east midday as the surface low lifts into Iowa. As the low tracks across Iowa this afternoon a dry slot will develop, allowing for deeper mixing and deep instability development where we get clearing. Environmental winds increase in this slot with HREF mean gusts of 35- 40+ mph gusts in southeast Iowa. Soundings indicate periods of 40- 50+ kts at the top of the mixed layer in southeast Iowa, which may allow for an occasional stronger gust this afternoon. Conditions are better east of the area into the Quad Cities CWA where the wind advisory has been issued.

The surface low reach south-central Iowa by around 18z and pushes to eastern Iowa by around 23z which will define the narrow window for severe storms here. Instability in that clear slot is expected to increase to 1000-1500 J/kg of MLCAPE along with ~40 kts of 0-6 km shear which is more than sufficient for convective initiation. Mid level lapse rates are around 7 C/km along with 150 m2/s2 0-1 km SRH. Expect that storms will initialize in central Iowa early this afternoon and quickly move east through the afternoon. Initial discrete to multicell clusters in central Iowa growing upscale as they move into eastern Iowa. All modes of severe weather are possible including large hail, damaging wind gusts, and tornadoes. The tornado threat should be maximized in the vicinity of the surface low and with initial discrete storm mode.

Another upper level wave will amplify as it it move from the western to central US on Friday. The low track remains fair consistent across GFS and EC ensemble members, moving SW to NE across Iowa through the afternoon, fed by a 50+ kt LLJ. Instability builds through the afternoon with 2000+ J/kg MLCAPE and 40-50 kts of 0-6 km shear to organize storms. Again anticipate initial discrete development, growing upscale as it moves into eastern Iowa. These cells may remain discrete longer than the Thursday storms, and CAMs indicate a line of supercells across central Iowa before the line-out into eastern Iowa. This evolution is supported by the expected mesoscale environment. Lapse rates steepen to 8 C/km in the mid levels with 300+ m2/s2 of 0-1 km SRH. As such, once again expect all modes of severe storms on Friday including large hail, damaging wind gusts, and tornadoes.

LONG TERM /SATURDAY THROUGH WEDNESDAY/

Issued at 309 AM CDT Thu Apr 2 2026

Wrap around precipitation skims far northern Iowa on Saturday, however will be of little impact with temperatures warm enough for this to fall as light rain. Cooler behind the cold front with highs on Saturday in the 40s. By Sunday temperatures warm into the 50s with dry conditions. Cool and benign conditions through the first part of next week, becoming more active later in the week.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/

Issued at 1125 PM CDT Wed Apr 1 2026

IFR or lower conditions will prevail overnight as showers, light fog, and very low clouds blanket the area. Showers will decrease in coverage/frequency around midday Thursday and we will see some gradual rising of ceilings, mainly at DSM and OTM. A brief period of thunderstorms may impact DSM/ALO/OTM around 18-23Z, followed quickly by a cool front with temperatures turning to roughly northwest by the end of the TAF period. Low clouds and fog may redevelop Thursday night, but confidence is low and this will be addressed in later TAF issuances.

HYDROLOGY

Issued at 130 PM CDT Wed Apr 1 2026

Continued short and long term flooding considerations exist due to the imminent multi-day seasonally moderate to heavy rainfall event, mainly across the southeast half of the CWA.

Short term considerations include potential ponding and low-end flash flooding. Soil moisture values are generally running near to below normal. That data combined with the QPF suggests any ponding and flash flooding will be mainly rate vs. amount driven, with the greatest risk in urban areas.

Longer term considerations include potential river flooding. GFS- and NBM-forced National Water Model, HEFS and QPF ensemble hydrographs indicate the most likely scenario will be moderate to significant within-bank rises. A few locations may reach flood stage, however minor flooding would be expected at most if it occurs. The peaks on most rivers will occur this weekend into early next week. Greater concern is the next few days of rainfall may set the stage for more significant impacts going forward if the wet pattern continues.

DMX WATCHES/WARNINGS/ADVISORIES

None.