Arctic Cold Continues, Snow Chances Rise Later This Week
KEY MESSAGESArctic Cold Today and Tonight: Bitter cold will persist as temperatures struggle to stay above zero, with wind chills ranging from -20°F to -35°F, especially in northern Iowa.
Snow Chances: Light snow may develop Tuesday night into Wednesday, with another chance for flurries or light snow late Thursday. Snow accumulation is expected to remain minimal.
Relief Coming Tuesday: Warm air advection will slowly lift temperatures through Tuesday, with highs gradually returning to near seasonal norms by Wednesday.
Short-Term Forecast (Today through Tuesday)
Confidence: HighA broad upper trough remains entrenched over much of the central U.S., with a 500mb low sitting between the Great Lakes and Hudson Bay. This setup, along with a 1040+mb surface high anchored over the northern Plains, will continue to funnel Arctic air into Iowa today. Temperatures will remain very cold, especially in northern Iowa, where conditions will feel bitter, and wind chills will be dangerously low—ranging from -20°F to -35°F.
Cloud cover will increase throughout the day as a shortwave trough rounds the upper low, bringing the potential for high cloud bands, HCRs (horizontal convective rolls), and scattered flurries. While snowfall will be light, these flurries may add a brief dusting in areas of higher moisture content. As the surface high dislodges eastward tonight, skies will clear, and conditions will become favorable for radiational cooling. The coldest temperatures will likely occur overnight, especially in northern Iowa, where lows could fall as low as -20°F or colder. However, with light winds (5-10 mph), the actual temperature drop may be limited, but wind chills will still be dangerous.
On Tuesday, warm air advection will begin to lift temperatures, gradually breaking the Arctic cold snap. As the cold air mass shifts east, temperatures will rise through the single digits and teens during the day, and continue to warm slightly overnight.
Extended Forecast (Wednesday through Friday)
Confidence: MediumThe warming trend will continue on Wednesday, with temperatures returning to more seasonal norms. Highs will be in the 20s and 30s, which is closer to what we expect for mid-January. Northwesterly flow aloft will persist, which means periodic chances for light precipitation.
The first of these windows for light snow will open Tuesday night into Wednesday, as thermal forcing from mid-level fgen (frontogenesis) supports a band of snow sliding across the state from northwest to southeast. The highest chance for measurable snow will be across northern Iowa, with a 30-60% chance for precipitation. Accumulations are expected to remain light, with up to 1 inch possible in some areas, but with the dry conditions left behind by the Arctic air, moisture availability will be limited. As a result, the snow may not be widespread.
A second opportunity for light snow or flurries will occur late Thursday into Friday as another shortwave drops through the region. This disturbance may bring a fresh round of light snow, primarily to western Iowa, but models are starting to diverge, so confidence in exact timing and location remains low. Further snow chances are possible into the weekend, but the forecast remains uncertain at this point.
Looking Ahead:
By the weekend, the upper-level flow will flatten out, and though additional light snow or flurries may be possible, confidence in timing and location is low. Temperatures will continue to gradually rise toward more typical January levels, but until then, the cold temperatures will continue to dominate, making travel and outdoor activities potentially hazardous due to the extreme cold.
