textproduct: Des Moines

KEY MESSAGES

- Hot and dry conditions today lead to near record temperatures and critical fire weather conditions. A Red Flag Warning will be in effect this afternoon.

- Milder temperatures and breezy conditions develop on Sunday. A few sprinkles are possible over northern Iowa early Sunday morning.

- Mild conditions continue to start the work week, but another warming trend is expected into mid-week.

SHORT TERM /THROUGH MONDAY/

Issued at 306 AM CDT Sat Mar 21 2026

Our late week warm spell peaks today as the heat dome to our west collapses eastward into the state. 850 mb temperatures in the upper teens to near 20 celsius will develop overhead, resulting in very warm air over Iowa. Highs will climb into the 80s for much of the forecast area today, with some locations in southwest Iowa making a run for 90 degrees. This unseasonable heat will not only threaten daily records, but will also flirt with monthly records for March. The monthly records will be harder to reach than the daily, especially in northern Iowa, but Des Moines' forecast high for today is within 3 degrees of it's monthly max and Ottumwa's forecast high is within a degree. Observed highs have been overperforming the forecast for the last few days, so have accounted for this by increasing max temperatures toward the higher end of guidance, but still wouldn't be surprised to see some locations exceed highs by a degree or two. Needless to say, today will be an anomalously warm day for March. For more details on daily and monthly climate records, see the climate section below.

In tandem with the anomalously warm conditions today will be anomalously dry conditions and critical fire weather conditions this afternoon. This will be especially true over southwestern into central Iowa, where a Red Flag Warning will be in effect this afternoon. Relative humidity values in the Red Flag Warning area are expected to drop below 20 percent, with some locations falling into the mid teens by the afternoon. As indicated in last evenings discussion update, relative humidity values in the teens are fairly rare in Iowa and a good indicator of the exceptionally warm and dry airmass making it's way eastward into the state. Grasses and fuels across the state also remain dry and fully cured. The combination of completely dry fuels, hot temperatures and dry air will result in a high likelihood for ignition in grasses and cropland, as well as ample opportunity to spread. That all said, there is one piece missing from the equation, that being strong winds. With a relatively weak pressure gradient overhead, winds aloft won't be overly strong. Likewise, downward momentum transfer of what wind energy does exist aloft will be negated by a warm air advection regime and height falls. This will ultimately keep winds more marginal compared to a typical red flag event, with sustained winds around 10 to 20 mph and gusts up to around 25 mph at times. The only feature to keep an eye out for is a weak trough passing through in the morning, which could give a brief enhancement to pressure gradients and winds at the surface. Even then wind gusts generally remain under 30 mph. This should help mitigate a significant fire weather event today, although burning is still highly discouraged. Fires will still develop easily in the hot and dry conditions, even if erratic behavior won't be as likely with the weaker winds.

Our anomalously warm and dry conditions come to an end Saturday night, as a surface low brings a cool front through the state. High temperatures on Sunday behind this front will still be seasonably warm for March, but milder compared to highs yesterday and today, generally in the 40s to 50s and low 60s from north to south. As the front passes through and low level lapse rates steepen Sunday morning, there will be a brief window for brief light rain/sprinkles over northern into northeastern Iowa. However, a dry subcloud layer will steadily grow as the surface heats after sunrise on Sunday, negating light rain/sprinkle chances farther south in the state. Finally, breezier winds will develop with the cold air advection and tighter pressure gradients along and behind the cold front on Sunday. Northerly winds of 20 to 25 mph are expected, with gusts up to 35 mph possible at times. Fortunately, cooler temperatures will keep RH values at bay, negating fire weather concerns on Sunday. Dry and mild conditions with light winds will develop on Monday as surface high pressure sits over the state.

LONG TERM /MONDAY NIGHT THROUGH FRIDAY/

Issued at 306 AM CDT Sat Mar 21 2026

A roughly zonal flow pattern develops over the US to start next week, which will include multiple lobes of energy passing through it. Models aren't great at picking out these weaker features, especially at longer ranges, but there are hints of a few weak shortwaves ejecting through Iowa both Monday night into Tuesday and then again Tuesday into Wednesday. Either of these could bring some light showers to the state, but lacks a strong signal within guidance and will need to wait to have any confidence in precipitation chances next week. Otherwise, temperatures look to steadily warm again through mid-week as another 500 mb ridge builds over the southwestern CONUS.

AVIATION /06Z TAFS THROUGH 06Z SUNDAY/

Issued at 1040 PM CDT Fri Mar 20 2026

Confidence remains high that VFR conditions will prevail through the period. Light winds becoming from a southerly direction overnight will strengthen above 12 knots from the southwest by late Saturday morning into the afternoon hours. As a front drops into the state late in this valid period, surface winds will switch direction first while low level winds will increase before switching. This will yield a period of low level wind shear that will extend past 6z Sunday.

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 from 1 PM this afternoon to 10 PM CDT this evening for IAZ033-034-044>047-057>060-070>073-081>083-092>094.