Iowa is set to be impacted by two weather systems today that will lead to slick roads this afternoon and evening and dangerous cold by Thursday morning.
System 1: There is a strong upper level low lifting out of the southwest US today. It is bringing heavy rain and snow across Oklahoma, Kansas and Missouri and the northern edge of the precipitation shield and cloud cover may lift far enough to the southern and southeast counties of Iowa. Snow is possible through the southeast part of the state through the afternoon and evening.
System 2: The second weather system is a strong arctic front that is moving across the state today. This will bring snow showers and a dramatic temperature drop of 15 to 20 degrees within one hour, dropping parts of Iowa from above freezing to below freezing fast. Winds will become blustery out of the northwest.
Clouds are streaming in from the south due to the southerly system and from the north from the arctic front. Warm air advection may lead to the development of snow across southern and southeast Iowa from noon on. Temperatures will rise to the upper 30s through afternoon.
The arctic front will quickly be dropping south during the afternoon across Northern Iowa. A Winter Weather Advisory is in effect starting at 3 PM for Northern Iowa to give a heads up on poor road conditions due to slick roads and blowing snow. The front will lead to a 15 to 20 degree drop within the hour as it passes through the state.
Here is when the temperature drop to below freezing is expected to happen for a few Central Iowa communities:
Fort Dodge: 3 PM
Carroll: 4 PM
Ames: 5 PM
Des Moines, Creston and Grinnell: 6 PM
Lamoni: 7 PM
There may be some light drizzle ahead of the snow that will fall during the passage of the front. The drizzle and melting snow on pavement may quickly freeze when the temperatures drop. It could be especially slick on untreated pavement, parking lots and sidewalks.
Cold Settles In:
An arctic high pressure center will place itself over Iowa early Thursday morning. Temperatures will drop below zero with strong northerly winds. The combination of the two will lead to dangerous wind chills from -15 to -20 below in Central and Southern Iowa and -20 to -30 below in Northern Iowa.
A Wind Chill Warning will be in effect for Northern Iowa on Thursday morning and a Wind Chill Advisory will be in effect for Central and Southern Iowa on Thursday morning.
The cold will not last long. The pattern will shift to a more mild southerly flow. Clouds will increase and temperatures will return to the low 40s for daytime highs during the weekend.