textproduct: Des Moines

KEY MESSAGES

- A few showers and non-severe thunderstorms possible far west late today and tonight.

- Thunderstorm chances increase from west to east Sunday and Sunday night.

- Monitoring potential for a significant severe weather event on Monday.

SHORT TERM /THROUGH SUNDAY/

Issued at 247 AM CDT Sat Apr 25 2026

A mostly quiet early morning across Iowa. A ribbon of mid-leve theta- e advection is leading to a region of showers and a few thunderstorms from southeast South Dakota and into north central Nebraska. Big picture wise, a large upper level low pressure remains over Saskatchewan today. A robust upper level system off the west coast of California, will begin to move east today and combined with the northern upper low, will begin to tilt the upper level flow more southwesterly. That flow will begin to increase the moisture transport into the state and gradually eroding the drier air currently in place in Iowa and will lead to increasing precipitation chances tonight and Sunday.

Expect mostly dry conditions today as low level easterly flow develops from near the surface up to around 5 kft. The one feature to watch with this easterly flow is the stratus that is currently over eastern Wisconsin and Lake Michigan. The steering flow for this stratus will keep pointing south for the next several hours before turning more northeast then east as that easterly flow develops this morning. That may bring some of this stratus into parts of eastern Iowa today. Mid to high level cloud cover will also increase over parts of western and northwest Iowa today as the theta-e advection aloft arrives through the day. CAMs and other guidance are suggesting a few thunderstorms will be translating east this afternoon and may reach parts of western Iowa later afternoon and into this evening. At this time, it appears this activity will begin to outrun the feeding instability, leading to a weakening in that activity as it moves towards the western DMX CWA. A few thunderstorms could occur overnight as limited instability develops.

LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/

Issued at 247 AM CDT Sat Apr 25 2026

Lee side cyclogenesis will occur over southeast Colorado on Sunday as the California upper level system translates eastward. Waves of theta-e advection lifting into Iowa will intensify as the low deepens and moves into western Kansas. This will lead to increasing thunderstorms chances, especially later in the afternoon and in particular overnight. A few storms with large hail are possible.

The western upper level system will lift into Nebraska and southeast South Dakota on Monday while surface low pressure deepens as it lifts north/northeast across Iowa from late morning and through the afternoon. This is a setup that has the potential for significant severe weather across parts of the state. Continue to monitor the strong tornado potential with a large amount of low level shear and helicity within the 0-1 km layer and increase streamwise vorticity ingestion potential for any organized supercell storms. A few spot checks over parts of central and southern Iowa suggest the 0-1 km streamwise vorticity values may top 0.03, which is quite high. In addition the upper level jet will be cutting across the warm sector, which would also support strong tornado potential. Stay tuned, there remains some uncertainty on the exact track this system takes. SPC now has an Enhanced risk for severe weather Monday with a 45% hatched areas over parts of Iowa.

No significant weather is anticipated for the rest of next week as severe iterations of high pressure remain the primary influence. High temperatures in the 50s and 60s will be near to slightly below seasonal averages. Perhaps a period or two of frost may occur.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 633 AM CDT Sat Apr 25 2026

VFR conditions and northeast to east wind to start the period. Conditions are expected to remain mostly VFR through the period with the wind gradually becoming more easterly. Monitoring IFR stratus in vicinity of Lake Michigan that will begin moving west this morning. There remains a low chance it could reach the KALO/KOTM vicinities. A few showers or storms could reach KFOD/KDSM tonight.

DMX WATCHES/WARNINGS/ADVISORIES

None.