textproduct: Des Moines

KEY MESSAGES

- Cold Weather Advisory through 3 am Saturday.

- Light snow possible Saturday with minor accumulations mainly far south.

- The remainder of January is trending below normal with periodic waves of cold air arriving in Iowa.

DISCUSSION

Issued at 251 PM CST Fri Jan 23 2026

Arctic high pressure is ridged into Iowa this afternoon with the center to the north over west central Minnesota. Temperatures at 2 pm remain below zero for the entire area which is impressive over the snow free areas over central and southern Iowa. The coldest temperatures are with the light snow cover over northern Iowa with reading of 7 to 11 below zero. High level clouds have been streaming over the southern half of the state today and the resultant filtering of solar energy is in part responsible for temperatures remaining below zero over the snow free areas.

A more organized mid level cloud layer around 8 kft extends from northern Missouri into central Nebraska. That layer is closely linked with with moisture and theta-e advection around 750 mb. That cloud cover has been mostly stagnant so far today with little progress northeast but it will begin to make progress later this afternoon and tonight. Will be using this cloud deck as a proxy for the low temperature forecast tonight and have leaned closer to the NBM 75th percentile over the southwest to near to slightly below the NBM 50th northeast. Dew points over northeast Iowa are in the low 20s below zero over northeast Iowa. The high level cloudiness shouldn't have much impact of any radiational release overnight. The high pressure center will move southeast and winds will diminish to less than 5 mph over the northeast. With current temperatures near 10 below at Waterloo and Mason City and considering the dew points and some light snow pack, a run for 20 below zero is possible. With the winds becoming light, wind chill values will rise just above advisory criteria overnight and have kept the end of the advisory at 3 am CST.

Light snow chances over southern Iowa are the other forecast challenge this forecast cycle. Numerous model guidance are trying to bring at least light QPF south of Interstate 80. Several things to consider here also. First, any gulf moisture is cutoff well to the south of Iowa. There is good mid-level moisture transport originating from the Pacific and that extends up into southern Iowa. This is what is moving the mid-level cloudiness over the area tonight. There is light snow and cloud bases near 3 kft over western Kansas and far western Nebraska. This moisture will try to move east towards Iowa, which will have the Arctic high pressure nearby. Typically the dry air from these very dry/Arctic high pressure systems wins out and results in less precipitation that model guidance. Model RH cross-sections across Iowa are a less than impressive 75-85 percent. Typically look for 75 percent for ice nucleation and even if that is achieved, the snow flake microphysics process will be impacted, likely resulting in smaller flake dynamics that may evaporate more easily and certainly will result in a low snow to liquid ratio. The other consideration is that with such a cold air mass, it does not take much moisture to have some saturation but still the lack of low level moisture advection should be a big limiting factor here. Therefore, have limited snow chances more south and backed off snow amounts but did keep up to 2 inches possible near the Missouri border. At this point, no headlines are expected, especially with the light wind.

Beyond that, it still looks to be a cold end of January with several surges of cold air southward with a mostly predominant northern flow from central Canada to Iowa. There should be a could light snow chances embedded in the forecast and with the greatest chance projected around Wednesday, but that is a ways out trying to track temporal and spatial placement of and short waves.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1135 AM CST Fri Jan 23 2026

VFR conditions are expected much of the period with the northerly winds diminishing and gradually turning more northeasterly. Clouds will increase during the period and there is the potential for light snow over southern Iowa Saturday morning with the main impacts near KOTM. MVFR cigs may also arrive at KOTM late in the period.

DMX WATCHES/WARNINGS/ADVISORIES

Cold Weather Advisory until 3 AM CST Saturday for IAZ004>007- 015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097.