textproduct: Des Moines

KEY MESSAGES

- Generally quiet through the coming week, with varying temperatures but low precipitation chances (<20%). Any rain that does fall will be light and of no impact or consequence.

- Temperatures will gradually warm through the first half of the week, likely peaking Thursday when highs will range in the 70s across much of central into southwestern Iowa, and possibly reach 80 degrees in a few areas. Cooler weather will then return in the latter part of the week.

SHORT TERM /THROUGH MONDAY NIGHT/

Issued at 137 PM CDT Sun Mar 22 2026

In wake of the front that surged through Iowa last night, brisk and gusty north breezes have helped bring notably cooler air into the region. Current temperatures range from the upper 30s in northern Iowa to low/mid-50s in southern Iowa, roughly 40 degrees colder than yesterday but still only a little below seasonal normals (after Saturday was about 30 degrees above normal). Skies are also mostly cloudy this afternoon with both low and high cloud decks affecting parts of Iowa, however, satellite imagery indicates the high clouds will clear from the west by tonight. The large deck of low stratus clouds that is blanketing Minnesota and much of northern Iowa is more problematic to forecast. A a surface high pressure ridge builds in from the north tonight, forecast soundings illustrate drier air filtering into our area and recent satellite imagery depict corresponding erosion of the low cloud field. However, with winds going light and variable overnight as the ridge axis settles in, any stratus that remains at that time may simply persist and thicken in the ridge. Deterministic models are split on which solution will unfold; whether the stratus will erode entirely from our area (most global models and GFS cores) or whether it will spread back into nearly our entire area (RAP), or somewhere in between (HRRR). This will have a significant impact on overnight temperatures given the light/calm winds. However, the resulting range of low temperature probabilities is of little public impact given the season and lack of precipitation or snow cover. Have updated the forecast for tonight to increase cloud cover through the evening but diminish it overnight, and nudged temperatures down just a bit toward a clearer/cooler solution, but will continue to monitor for updates through the night.

Monday will be sunny, with light winds and high temperatures around the lower 50s as the surface high pressure area slowly slides off to the east late in the day. Meanwhile, a broad low pressure trough will form along the front range at the footstep of the Rockies in Colorado and Wyoming. Between that trough and the aforementioned high to the east, a tightening pressure gradient will support a return of southerly low-level flow across Iowa Monday night. Meanwhile, a ribbon of frontogenetical forcing aloft will translate eastward across the Midwestern states Monday night, in associated with a weak shortwave impulse moving overhead. This forcing will help to re-saturate the column aloft and should provide enough lift to generate light rain, however, the forcing will be slowly weakening as it moves eastward over Iowa, and forecast soundings also indicate a persistent near-surface dry layer associated with the departing surface high. Given these factors, it is likely our forecast area will see only sprinkles or a few very light showers, mainly in the western and southern counties, and have added 10-20% PoPs accordingly. Again, no impacts would be expected from this precipitation.

LONG TERM /TUESDAY THROUGH SATURDAY/

Issued at 137 PM CDT Sun Mar 22 2026

By Tuesday another 500 MB high pressure area will coalesce over the far southwestern U.S., bringing a return of heat to that area in somewhat of a repeat of last week. However, this time around the west northwesterly steering flow over the northern U.S. will extend farther southward, having more influence over Iowa for the most part and shunting the heat associated with the southwestern low farther southward. Even so, initially the southwestern high will exert some influence up into the Midwest on Tuesday and Wednesday, even as south southwesterly surface breezes prevail across Iowa and support a steady warming trend. After Monday highs in the lower 50s, Tuesday will see highs around the lower 60s and on Wednesday temperatures will climb back into the 70s in our central and southwestern counties, and may even reach 80 again in the southwest. There are some fleeting rain chances from late Tuesday through Wednesday associated with the warm air/moisture advection and weak and nebulous forcing aloft, however given the lack of organized lift and, once again, low-level dry air in place, have held off on any meaningful PoPs with only a token sprinkle mention in southern Iowa late Tuesday. Any rain that does fall during this time frame will be of no consequence or impact.

Between Wednesday night and late Friday a series of shortwaves will move through the 500 MB flow, shunting the warm weather to the south as referenced earlier, and also pushing another cool front southward through Iowa in the latter half of the week. Given the relatively subtle nature of the shortwaves and the mid-level steering flow oriented roughly parallel to the surface front, long-range models are showing a large degree of variability in timing of frontal passage through our area, which is predicted anywhere from late Wednesday night to Thursday night. The resulting large spread of temperature solutions is reflected in box-and-whisker plots of NBM/ensemble output, with Thursday high temperatures showing the largest variability of the week. When the front does move through it will carry some low/light precipitation chances and bring notably cooler weather heading into the weekend, again in a similar (but less extreme) manner to what has occurred from yesterday into today.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 107 PM CDT Sun Mar 22 2026

Low stratus clouds continue to affect much of northern into central Iowa this afternoon. MVFR ceilings prevail at FOD and MCW, but have mostly avoided or only intermittently impacted ALO and DSM thus far. As dry air steadily filters in from the north this low cloud deck should continue to erode, but confidence in the timing and extent to which it will do so is low. Have maintained prevailing MVFR at FOD/MCW into this evening, but largely kept it out of the remaining terminals. It remains to be seen whether the stratus will redevelop/re-expand overnight as well, but it appears more likely the drier air will win out and VFR should prevail late tonight into Monday. Meanwhile, strong north winds this afternoon will subside rapidly around this evening and become light and variable tonight.

DMX WATCHES/WARNINGS/ADVISORIES

None.