02/21/18 Ice Storm: MO/IL/IN

Dan Robinson

Staff member
Jan 14, 2011
St. Louis
The NAM and Euro have been consistent for the last 36 hours on a narrow (50-70 miles) corridor of heavy icing from Springfield/Joplin Missouri through central Illinois late Tuesday night into Wednesday afternoon as a shallow Canadian airmass undercuts several rounds of heavy precipitation. The GFS has not shown ice storm-level QPF, showing a slower encroachment the cold air southeast.

NAM ice accretion output have been in excess of 1 inch in the swath from the KS/MO/AR border area through St. Louis into central IL by late Wednesday.

The main limitation I see with this event is the marginally subfreezing surface temperatures of 30-32F, with much of the forecasted icing shown less than 100 miles west of the freezing line. Just a slight uptick in temps or slowdown of the cold front could completely wipe out the icing potential.
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