textproduct: Des Moines

KEY MESSAGES

- Warming trend continues today through mid-week. Highs in the 70s to near 80 possible on Wednesday and Thursday.

- Breezy and warm conditions on Thursday may lead to elevated fire weather concerns, especially over central and southern Iowa.

- A few showers and/or thunderstorms are possible in southern Iowa on Thursday afternoon, but the main thunderstorm risk resides south and east of the area.

SHORT TERM /THROUGH THURSDAY NIGHT/

Issued at 343 AM CDT Tue Mar 24 2026

The status quo generally continues across the area today, although return flow behind the departing surface high pressure will allow temperatures to warm roughly 5 to 10 degrees higher than yesterday. We'll see some brief clearing early this morning, but more mid- and upper level cloud cover will drift across the state through the day as another subtle shortwave and coincident moisture drift overhead. High resolution models continue to produce weak reflectivity over the area this afternoon and evening as the wave moves through but, similar to last night, model soundings show a healthy dry layer still in place at the surface. The southerly flow regime today will help to moisten the low levels and eat away at the dry layer, but it still appears unlikely many hydrometeors will reach the ground before evaporating. Therefore, while a stray sprinkle is possible Tuesday afternoon, precipitation chances are very low.

The warming trend continues into Wednesday as warmer 850 mb temperatures aloft and south southwesterly flow at the surface continues to advect warmer air into the state. Intermittent cloud cover will work to filter sunshine during the day but clearing in the afternoon, especially over southwest Iowa, will only help to boost mixing and temperatures in the area. Highs on Wednesday are expected to climb into the 70s northeast to near 80 in the southwest. Higher dewpoints advected northward by the gulf moisture stream Tuesday night into Wednesday should help to keep RH values from falling to critical levels, although they still bottom out around the 30 to 40 percent range. Winds won't be overly breezy, either. Therefore, while some slightly elevated fire weather concerns are possible in southern Iowa, most of the state should avoid critical fire weather conditions.

Thursday continues to be the main "weather" day of the week, as longwave troughing drifts southward into the northern US and pushes an elongated surface low through the area. Ahead of this low, strong southerly flow and warm air advection will attempt to boost temperatures into the 70s and 80s again on Thursday, although the temperature forecast will be dependent on how quickly the low and coincident cold front drop into the area. Current consensus in the deterministic guidance, as well as the NBM, is for this front to be about halfway through Iowa by 18z on Thursday, leaving time for south central into eastern Iowa to warm up nicely during the day. Areas farther north will see the surface front pass through sooner and therefore see the warming trend shut off as cold air advection kicks in around mid-day. That said, a warm nose aloft behind the initial boundary will keep temperatures relatively warm until the mid-level front passes through in the evening. This will help keep temperatures generally in the 60s even behind the boundary on Thursday.

Breezy conditions will also develop on Thursday, as pressure gradients increase overhead. The strongest winds will be with the cold air advection behind the front, but breezy conditions are expected throughout the area. The combination of breezy winds with the warmer temperatures suggests the potential for elevate fire weather conditions Thursday afternoon. Fortunately, 50+ dewpoints will accompany the warmest air in southern Iowa and help to mitigate RH values plummeting. This will create a balance of "higher temperatures, higher dewpoints" in southern Iowa and "lower temperatures, lower dewpoints" farther north, resulting in a broad area of 35 to 45 percent minimum RHs across the state. The breezy winds and dry fuels could still lead to increased fire spread, so we'll want to watch how dewpoint/RH trends behave through the next few days.

Finally, the passage of the surface low and cold front on Thursday could also bring some shower and/or thunderstorm potential, mainly over southern Iowa. A warm nose aloft should help to negate convection in the warm sector for much of the day Thursday, but guidance does still try to produce a few showers/storms along the cold front over southern Iowa Thursday afternoon and evening before exiting the area. Instability around 500 to 1000 J/kg and plenty of deep layer shear over southern Iowa Thursday afternoon will be supportive for a few stronger updrafts, but the better severe thunderstorm environment looks to be south of the Iowa/Missouri border and over Missouri and Illinois. Given this, the storm prediction center only has a general thunder outlook for our area, with a marginal risk (level 1 of 5) for severe weather just south and east of our forecast area. This seems reasonable given the uncertainty of storm initiation along the front in Iowa and the borderline severe weather environment. That said, will want to watch for any slowing down of the low/cold front, as this could allow the more unstable air to work farther north into our forecast area.

LONG TERM /FRIDAY THROUGH MONDAY/

Issued at 343 AM CDT Tue Mar 24 2026

Regardless of what time the front comes through Iowa Thursday, it will usher in a couple days of quiet and cooler weather once more. High pressure will dominate again from Friday into Saturday, with Friday afternoon high temperatures only in the 40s to lower 50s across the area. However, temperatures will begin warming again over the weekend and into early next week. Looking even further ahead, it does appear the weather pattern will become generally more active next week, as broad troughiness develops across the western and central U.S., and moisture and instability increase in our region.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 622 PM CDT Mon Mar 23 2026

VFR conditions will prevail through the period. High clouds have expanded across Iowa and will last through the evening, pushing east after 06z. Additional high clouds will move across Iowa on Tuesday. Winds remain out of the east-southeast through the period.

DMX WATCHES/WARNINGS/ADVISORIES

None.