textproduct: Des Moines

KEY MESSAGES

- Conditional severe thunderstorm threat with all severe hazards possible in far southeastern Iowa this afternoon into early evening.

- Additional showers and storms persisting south overnight. Hail is the primary threat. - Light rain transitions to light snow over northwest and northern Iowa. Accumulations generally under an inch, but a few slick spots possible

- Elevated fire weather conditions with breezy and dry conditions Wednesday.

- Gusty winds and elevated fire weather conditions again on Thursday. Winds persist overnight into Friday morning.

SHORT TERM /THROUGH THURSDAY NIGHT/

Issued at 251 PM CDT Tue Mar 10 2026

>> SEVERE THUNDERSTORM POTENTIAL THIS AFTERNOON INTO TONIGHT

Surface analysis shows a warm front draped over far southern into southeastern Iowa early this afternoon, which will act as the focal point for thunderstorms in the Mississippi River valley region this afternoon into the overnight hours. As it stands currently, a very small portion of our forecast area is south of this boundary. The front is expected to lift northward slightly as the parent surface low approaches the area this afternoon, which may introduce a small area of the state to the warm sector before the trailing cold front quickly sweeps in behind the surface low. This warm sector will be where the greatest risk for severe weather will reside, but will likely be limited spatially for our forecast area. Similarly, storms will need to actually initiate for this threat to materialize in our forecast area. This likely won't happen until the cold front moves through late this afternoon and evening, providing enough mechanical lift to overcome the warm nose aloft that is otherwise preventing convection today. Depending how far north the low and warm front are able to push will determine how long the severe threat is present in our area, with a more northerly push introducing a relatively higher chance for severe weather, and less northerly push likely keeping the storms completely south and east of here.

That all to say, the window for severe weather this afternoon is small but it does still exist. Any storm that does develop in this warm sector will have access to 2000 to 3000 J/kg of SBCAPE and 50 to 60 kts of effective shear. All forms of severe weather will be possible with these warm sector storms, including large hail, damaging winds and even a tornado. With the 40 to 50 mph storm motions, this threat would be fairly short-lived, but could certainly cause impacts for an hour or two today. We will be monitoring trends over southern Iowa closely through the next few hours.

As we get into the overnight hours, confidence is decreasing in elevated storms north of the cold front, but a low end potential still remains as the low level jet ramps up over night. Some instability remains aloft in the southeastern half of the state after the surface cold front passes, although moisture isn't overly plentiful in the mid-levels. If a storm can go, likely along the trailing 850 mb boundary, there will still be plenty of shear and roughly 1000 J/kg of MUCAPE to take advantage of in southern Iowa, suggesting elevated hailers are possible overnight. Again, this would be dependent on storms taking off, which short range guidance isn't bullish on, but will be worth monitoring overnight.

>> LIGHT RAIN TRANSITIONING TO LIGHT SNOW EARLY WEDNESDAY MORNING

In addition to the shower and thunderstorm chances south and east, we will see a trailing band of light rain transitioning to light snow in northern Iowa overnight into early Wednesday morning. Snow chances look most likely over northwestern Iowa where temperatures will be coolest, with light rain looking more likely into central and eastern Iowa as the band progresses south and eastward. Moisture availability to this band isn't overly plentiful, but there will be a healthy amount of lift through the dendritic growth zone, especially over northwestern Iowa. This implies we could get at least a short burst of more efficient snowfall, leading to brief reduced visibilites and a few slick spots over northwestern into northern Iowa. Similarly, this snowfall will be accompanied by cold air advection and gusty winds, further emphasizing the potential for low visibility. Amounts should generally remain under an inch. As the band progresses farther into Iowa, it experiences drier air and therefore struggles with saturation. Therefore, not expecting widespread impacts from this snowfall, but certainly potential for some slick travel, especially over northwest into northern Iowa.

>> ELEVATED FIRE WEATHER CONCERNS WEDNESDAY

Cold air advection behind the departing system will lead to gusty winds and dry conditions throughout the day on Wednesday. Temperatures won't be as warm, but relative humidities still drop into the upper 30s to low 40s over the western and southwestern portions of the area through the afternoon, bringing another day of elevated fire weather concerns. Vegetation remains dry and dormant, and any light precipitation that occurs will likely dry up with the strong winds and increasing sun through the afternoon. Therefore, burning should be done with extreme caution or avoided on Wednesday. Winds should remain sub-advisory, but gusts over 30 kts are possible at times through mid-day.

>> GUSTY WINDS, ELEVATED FIRE WEATHER CONDITIONS AND LIGHT RAIN THURSDAY INTO EARLY FRIDAY

Another system will drop southeastward toward Iowa on Thursday, bringing a push of warm and dry west southwesterly air into the area, as well as stronger winds aloft that will work to mix down to the surface. With warmer, drier and windier conditions possible Thursday, we are monitoring the need for fire weather headlines closely. Temperatures will warm into the upper 50s to near 60 in western Iowa, with low to mid- 20 degree dewpoints advecting in. This has dropped our relative humidity values into the mid to upper 20 percents. Likewise, a 40 to 50 kt jet noses up into western Iowa Thursday afternoon, making the depth of mixing very important. The main sticking point for both strong winds and fire weather concerns will be the cloud cover overhead, which would limit mixing if it comes to fruition. The warm air advection regime will also limit downward momentum transfer of winds. So still some features to iron out as for how significant winds and fire weather conditions will become Thursday. Regardless, it looks like at least western and southwestern Iowa will see elevated fire weather conditions, the question is whether we reach red flag criteria.

Of greater confidence with the Thursday system will be the cold front passage bringing strong winds Thursday night into Friday morning. The CAA regime and height rises behind the cold front will be favorable for downward momentum transfer of the 40 to 50 kt jet behind the front. This is a prime environment for over- performing winds, but it will be occurring at night where inversions may play a role, albeit likely limited with cloud cover overhead. Have bumped up NBM winds through this timeframe, resulting in 35 to 40 kt gusts in northern Iowa. The need for any headlines will be assessed in the coming days. In addition to the winds, this system also brings a shot of light rain over northern Iowa Thursday night into Friday morning.

LONG TERM /FRIDAY THROUGH TUESDAY/

Issued at 251 PM CDT Tue Mar 10 2026

Gusty but cooler conditions develop on Friday behind the cold front, but then rebound again on Saturday as we get return flow ahead of yet another system dropping into the area. This will be occurring through the Saturday night into Sunday period bringing potential for more rain and snow to end the weekend. Much cooler temperatures also accompany this weekend wave. More on this in the coming days.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 1104 PM CDT Tue Mar 10 2026

Additional rain showers are expected to move into southern Iowa after 09z and through much of the morning, though the overall potential for storms is low. Otherwise, will see a larger band of rain switching to snow arriving into northwest Iowa after 09z and track east/southeast across the state. Could see a period of lower vsbys from more efficient snowfall over northern Iowa, with otherwise largely rain at KDSM and KOTM, though cannot rule out a brief transition to snow. Widespread MVFR/IFR ceilings are expected across the terminals until around 18z, before improving through the afternoon. Winds will become northwesterly over the next several hours, increasing as gusts up to 25-30 knots are expected.

DMX WATCHES/WARNINGS/ADVISORIES

None.