textproduct: Des Moines

KEY MESSAGES

- Hot and dry conditions through this evening, with near record high temperatures and critical fire weather conditions. A Red Flag Warning will be in effect this afternoon.

- Notably cooler on Sunday, but with temperatures still a little above seasonal normals. Stronger northerly winds are forecast during the day, supporting an elevated fire weather risk but not as critical as today.

- Generally quiet weather is forecast for the coming work week, with daily high temperatures in the 50s to 60s and low rain chances.

SHORT TERM /THROUGH SUNDAY/

Issued at 117 PM CDT Sat Mar 21 2026

A deep mid-layer thermal ridge is centered over the far southwestern U.S., near the Arizona/New Mexico/Mexico border region, resulting in record heat there over the last few days. The influence of this ridge has increasingly spread up into the Midwest, resulting in a pronounced warming trend here as well. After tying the daily record on Friday with a high of 79 in Des Moines, temperatures are soaring into the 80s across much of our service area today with gusty southwest breezes and sunny skies. Unfortunately the breezy and dry conditions lead to a critical fire weather risk today, especially in southern and western Iowa, and a Red Flag Warning is in effect for parts of that area through this evening. See the Fire Weather discussion section below for additional details.

Meanwhile, a broad and flattened mid-level shortwave trough is moving off the rockies into the northern High Plains today, and will scoot quickly across the upper Midwest tonight. In response to its approach, a broad surface low pressure trough has developed today stretching from near the Wyoming/Nebraska border east northeastward into southern Minnesota. This surface trough will sink southward through Iowa overnight as the parent system shoots by to the north, bringing first light and variable winds after sunset and then a surge of stronger northerly winds by Sunday morning, which will continue through the day and contribute to temperatures well below today's levels (though still slightly above seasonal normals in many areas). Some deterministic models are indicating the potential for sprinkles or a few very light showers associated with the trough passage, mainly in our northern and eastern counties early Sunday. Moisture will be very limited however, and have thus maintained only low (20-30%) sprinkle chances accordingly. High temperatures on Sunday will be partially dependent on cloud cover, which by most indications may be extensive in the morning but may largely break up during the day as supported by some forecast soundings (particularly the RAP and GFS). While the degree of clearing will influence resulting high temperatures by a few degrees, in any event it will be much less warm than today. Also, in spite of somewhat higher relative humidity values than today, the stronger winds on Sunday will still support an elevated fire weather risk. See the Fire Weather discussion section below for additional details.

LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/

Issued at 117 PM CDT Sat Mar 21 2026

For most of the coming week Iowa will remain beneath fairly brisk west northwesterly steering flow aloft, while a series of shortwave impulses move through the flow and provide a moderating influence on our temperatures. Initially, on Sunday night, a surface high pressure area will spread over the region and allow for light winds and mostly clear skies. As a result, by Monday morning temperatures will fall into the upper 20s to lower 30s across our forecast area. This will only be the first in a series of rapidly alternating surface troughs and ridges over the subsequent several days, which is typical of this flow regime. The net result is that temperatures will vary from near normal to above normal, with daily highs generally in the 50s and 60s during the work week. There will also be low (30% or less) rain chances during this time, associated with the passages of intermittent shortwaves but limited by a relative lack of moisture in the column. Overall it will be a quiet and unremarkable week of early spring weather.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1215 PM CDT Sat Mar 21 2026

VFR conditions will prevail through most of tonight, with southwest breezes this afternoon becoming light and variable overnight. A cool front will then sweep through after 06Z into Sunday morning, bringing stronger north northeast winds and low MVFR ceilings. At this time the low ceilings are most likely (>60%) at the northern terminals (MCW/ALO/FOD), and less likely (30%) at the southern terminals (DSM/OTM), so the 18Z TAFs are written accordingly. In addition, strong southwesterly winds are anticipated just above the surface over southern Iowa overnight, resulting in several hours of LLWS at DSM and OTM between approximately 04Z and 12Z.

FIRE WEATHER

Issued at 117 PM CDT Sat Mar 21 2026

Today...Winds have come around to southwest and increased to 10 to 15 MPH across the area, with intermittent gusts generally in the 20 to 25 MPH range. Meanwhile, soaring temperatures and slowly falling dewpoints have led relative humidity to crater, with values falling into the 15-25% range across about the southern and western half of our forecast area. While winds will only sporadically reach criteria, the very low RH below 20% at times combined with very dry and cured surface fuels supports the Red Flag Warning in effect for critical fire weather conditions across our southwestern and central counties through this evening.

On Sunday temperatures will be markedly lower, with forecast highs "only" in the upper 40s north to lower 60s south, leading to relative humidity minimum values of around 40% south to 55% north during the afternoon. However, winds will come around to northerly Sunday morning and be even stronger for much of the day, with sustained speeds near 20 MPH and gusts to 30-35 MPH possible. This will still support an elevated fire weather risk on Sunday, but not as critical as today's levels due to the higher relative humidity.

CLIMATE

Issued at 1231 PM CDT Thu Mar 19 2026

Forecast and Record Highs for Select Central Iowa Cities...

==================================================================== | Today Today March | Period | Forecast Daily Record/ Monthly Record/ | of City | High Year Year | Record ==================================================================== Des Moines 88 86/1938 91/1986 1878- Mason City 80 81/1938 84/2025 1903- Ottumwa 87 86/1938 88/1986 1923- Waterloo 82 83/1938 87/1986 1895- ====================================================================

DMX WATCHES/WARNINGS/ADVISORIES

Red Flag Warning until 10 PM CDT this evening for IAZ033-034- 044>047-057>060-070>073-081>083-092>094.