Our recent warm fall conditions will come to an abrupt halt to end the week with significant snow accumulations expected and much colder temperatures. A fast moving low pressure system will move from the Rockies into the lower Missouri River Valley by late Friday, with moderate to heavy snow along and north of its track. Wind chills may reach zero north by daybreak Saturday.
Snow or a rain/snow mix is expected to advance west to east across Iowa starting midday Friday, eventually changing to all snow area wide by Friday night before ending early Saturday morning.
Storm accumulations in the watch area are expected to vary from five to seven inches on vegetation, with lesser amounts due to melting on sidewalks and pavement. Confidence in snow amounts is not high at this point, however, due to uncertainties with regard to storm track and the degree of melting.
Winds of 10 to 20 mph during the snow may produce minor blowing and drifting and also help contribute to visibilities under a mile during periods of heavier snow. Roads will become wet initially and then slushy before snow begins accumulating. the combination of slushy and snow covered roads may lead to hazardous travel conditions, including during the Friday evening commute.