textproduct: Des Moines

KEY MESSAGES

- Snow possible across the north, central, and east this afternoon and evening. Low accumulations, but reduced visibilities expected.

- Prolonged period of snow showers and squalls expected for much of Friday. A Winter Weather Advisory is in effect. Sudden, intense visibility reductions likely, becoming whiteout.

- Cold Saturday with lingering snow chances northeast.

DISCUSSION

Issued at 255 PM CST Thu Jan 15 2026

Active period of winter weather upcoming beginning with the line of snow moving into the area this afternoon. The front associated with this activity slopes deep beyond the DGZ and is accompanied by low static stability, which will lead to reduced visibilities from bursts of snow, especially as better low-level saturation is fed by the midlevels over the next 6 hours. As far as evening commute impacts are concerned, the area from Waterloo to Ottumwa will see the most.

A PV anomaly provides additional lift tonight and will be accompanied by a pressure trough. Low static stability throughout the profile will again provide a boost to the fairly transient round of snow. Accumulations will be under an inch. Wind gusts will be on the rise overnight along and behind the trough and exacerbate impacts by blowing snow around. At the same time, the surface temperatures will be steady to rising in southern Iowa. The thermal front will lag behind, arriving for Friday morning.

Impacts become much more significant at this point. CAA will cool much of the profile and create unstable lapse rates above 700mb. Moisture will be lofted via the frontogenesis and saturate much of this same profile. This burst of snow will provide momentum transfer to mix higher winds--some over 40mph-- which could bring periods of white out conditions from the blowing snow. Accumulations will again be low enough that impacts will be tied to falling snow, but said impacts will be intense and sudden. Moisture will hang on post frontal in much of central and northern Iowa with the deep convective instability forming snow squalls for much of the daytime Friday, the peak being in the afternoon as SBCAPE exceeds 30 J/kg. Coverage of snow lessens in southern and northeast Iowa due to less moisture. Have issued a Winter Weather Advisory to cover the prolonged period of snow bursts and squalls. Another note for tomorrow is for central and southern Iowa where temperatures begin near or above freezing. Flash freeze potential is possible as the initial front moves through the morning. Whatever precipitation that accumulates may melt initially, but then refreeze on surfaces upon the front passing. This will lead to slick roadways and untreated surfaces. CAA continues after dark and will keep the PBL mixed, meaning snow showers will still be in play through at least 9pm. At some point, the top of the PBL will cool below the DGZ and cease much of the snow production.

Arctic air sets in this weekend and a vort max pivots around the parent low centered in Canada. Enough saturation remains that some high SLR snow will fall Saturday and Sunday as long as forcing lingers. Saturday will be cold with highs in the single digits.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 551 PM CST Thu Jan 15 2026

The overall main aviation concern is where will the narrow bands of snow showers or snow squalls set up and bring localized restrictions during the day Friday, potentially below IFR. Confidence is low in this regard with this weather being more than 12 hours from now. Continued to highlight this potential in the PROB30 groups largely maintaining similar restrictions from 18z and expanding into the afternoon hours.

Otherwise in the valid period, the first round of mainly light snow will be just east of an ALO to OTM line at the start of the period, but will be watching upstream light snow in the Dakotas that could push over at least MCW yet this evening. Otherwise overnight, winds will become from the northwest this evening and increase with gusts commonly between around 30 to near 40 knots on Friday.

DMX WATCHES/WARNINGS/ADVISORIES

Winter Weather Advisory from midnight tonight to 9 PM CST Friday for IAZ004>007-015>017-023>026-033>036-044>046. Winter Weather Advisory from 6 AM to 9 PM CST Friday for IAZ027-028-037>039-047>050-057>062.