Snow, Sleet, and Freezing Rain Followed by Arctic Cold Next Week

Short-Term Forecast (Today through Saturday)

Confidence: High to Medium

An Arctic high has moved across the Upper Midwest overnight, bringing some of the coldest air of the season to Iowa. However, temperatures will recover into the teens today as westerly flow aloft helps lift the cold air out of the region. Highs may be slightly lower in the south due to the reflective fresh snowpack, but temperatures will rise steadily through the day.

Later tonight, the surface ridge will exit, and the region will experience a significant warm air advection (WAA) as a deepening wave moves across the state. This will lead to the development of snow for much of the state, although the snow will be lighter than what was seen on Wednesday. Due to a warm nose aloft and limited ice introduction, snowfall will be mixed with sleet and/or freezing rain, especially along the Iowa-Missouri border. Snowfall totals will generally range from 1 to 2 inches across most of Iowa, with localized higher amounts possible in the northeast.

Saturday Forecast

Confidence: Medium

Saturday’s forecast remains uncertain due to the interaction of several waves over the Central Plains. Lee cyclogenesis will occur Friday night, which will bring the low-level jet (LLJ) into a WSW to ENE orientation by Saturday. The location and timing of this shift will affect the placement of the system's deformation axis and moisture plume, which will determine where the heaviest snow falls. The highest confidence of snowfall impacts is for eastern and southeast Iowa (50% confidence), but amounts will likely be limited due to the relatively low snow-to-liquid ratios (SLRs) associated with the warm air aloft.

Sunday and Beyond

Confidence: High

A weak wave is expected to bring light snow to the region Sunday, aided by weak lift and a prolonged residence time in the dendritic growth zone (DGZ). While this will not be a major snowfall event, it will bring additional light snow. The cold air will be reinforced, and lows will dip back below zero.

Looking ahead to early next week, another wave of colder air will arrive, making for an extremely cold stretch of days. Highs will be in the single digits, with lows in the teens below zero. It is highly likely that cold weather headlines will be needed due to the dangerously cold conditions.