textproduct: Des Moines

KEY MESSAGES

- Very low chance (<10%) for freezing drizzle/rain far northeast Iowa Sunday afternoon, otherwise breezy and dry for most

- Warmer and mostly dry for early week, with another low probability window (<10%) for wintery mix far northern Iowa Tuesday

- A more dynamic system late work week to watch, with rain/snow and temperatures gradually plummeting behind it

DISCUSSION

Issued at 244 PM CST Sat Jan 3 2026

The weak wave that brought light wintry precipitation to the Midwest region slowly continues to depart today, which clipped northeast Iowa this morning and brought some isolated light freezing drizzle to light snow, particularly over Mason City and Forest City to Clear Lake. This had led to some isolated slick areas on roadways in these areas, but has since then improved. Otherwise dry conditions cover the entire state into this afternoon, though remaining cloudy especially as lower clouds slowly spread across the area. The clouds, along with low level northwest flow has led to a rather slow increase in temperatures, with values in the 20s north of I-80 and in the 30s south. Mid-level ridging over the northwest CONUS today will allow for the remainder of the day to be relatively benign in terms of weather, as surface high pressure passes through this evening and departs southeast by Sunday. Overnight lows in the upper teens through the 20s are expected tonight into Sunday, warmest across southwest Iowa. Cannot rule out the potential for patchy fog over portions of western Iowa into Sunday morning given the gradual push of warm and moist air overhead, along with light winds, though this would dissipate after sunrise.

Through Sunday morning, a mid-level shortwave passing across the Dakotas and into Minnesota will bring an increase in moisture and forcing into the region, arriving into the afternoon to early evening. The higher moisture content and more favorable forcing looks to remain into Minnesota and Wisconsin, though weak lift into the far northeast portion of Iowa, along with some moisture is suggested, with CAMS indicating a window where light precipitation may fall in the far northeast Sunday afternoon to early evening. However, QPF output from various models indicate no precipitation accumulation outside of a few that output a trace at most. A further look at the low levels near the surface per soundings indicate that some moisture presence in the low levels and some directional shear (turbulence) is indicated per RAP Sunday afternoon, concentrated below a dry but prominent warm nose as warm air advection lifts into the region and surface temperatures hover just below freezing, though other members such as the NAM and GFS are a bit drier near the surface. Overall, there is a non-zero chance for at least freezing drizzle into northeast Iowa Sunday afternoon, though probabilities remain below 10% so have not included specifically in the forecast at this time and will continue to monitor trends over the next several hours, as any southerly shift in the system could increase these chances notably. Shifting low- level flow becoming southwesterly, along with a tightened pressure gradient with this system's passage will also result in increased winds across Iowa Sunday morning through the afternoon, with gusts up to 20-30 mph expected.

The start of the upcoming work week is expected generally to be on the dry side, with weak mid-level ridging moving in briefly Monday. This will be followed by a shortwave trough moving into the Central Plains into Tuesday, with another flip in 850mb winds back southerly, keeping high temperatures on the mild side through the 40s and even low 50s. Surface low pressure in relation to the shortwave looks to pass through Iowa, though the majority of favorable forcing for lift and moisture return stays north and east of the state. While the GFS keeps Iowa on the dry side, the Euro and NAM do indicate some moisture and weaker forcing into north/east Iowa, with temperatures near to just below freezing Tuesday morning that would suggest additional but low wintery precipitation chances. Considering the considerable uncertainty on the extent of moisture into Iowa at this time, have decided to keep the area dry in this forecast cycle and will continue to closely watch this system into early next week.

A change to mainly zonal flow into the Central Plains, along with a lack of moisture overhead into midweek will keep conditions dry and relatively quiet, with temperatures remaining more mild in the 40s to even possibly low 50s, though these forecast values may be tweaked a bit lower in the coming days if cloud cover looks more likely as was discussed in the previous forecast. Beyond midweek, long range guidance indicates a more notable change towards the end of the work week as a longwave trough deepens and lifts northeast into the Central Plains, with access to gulf moisture tracking northward just ahead of this feature late Thursday into Friday. Depicted from this is a rather dynamic low pressure system developing into the central CONUS, with Iowa in the warm sector into Friday morning followed by a push of much colder air behind it as it slowly departs into the weekend. This could mean at least rain to start, followed by some transition to wintery precipitation and quickly dropping temperatures. With this being several days out from this point in time though, more specific details are not well known but will be something to certainly keep an eye on through the upcoming week.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1127 AM CST Sat Jan 3 2026

Low clouds will continue to move across the state for the remainder of today and into Sunday, with MVFR conditions expected to be common across the terminals. There is a low chance for patchy fog over KFOD Sunday morning as it looks to develop across portions of western Iowa, though confidence is too low to include specifically at this time and will continue to monitor trends. Some improvement in ceilings may occur late in the period, with winds turning southeasterly through Sunday morning and increasing with gusts up to 20-25 knots.

DMX WATCHES/WARNINGS/ADVISORIES

None.