Winter Storm: Jan. 20/21

As mentioned in this mornings' post, the previous Winter Storm Watches have been upgraded to Winter Weather Advisories, Freezing Rain Advisories, or Ice Storm Warnings for portions of KS/NE/IA and other adjacent states. A low pressure system will move eastward into central Missouri, leaving areas to the north of the low in a position to receive freezing rain through much of the overnight and into Wednesday morning. Other areas along and south of the lows' path will also see precipitation, although it should remain above freezing and therefore only fall as rain. In fact, some areas may be able to hear a few rumbles of thunder as some instability aloft will create conditions for some isolated thunderstorms across extreme eastern Kansas and through central and southern Missouri.

Regarding the areas of freezing rain, expect the heaviest amounts to occur across portions of Iowa, mainly where the Ice Storm Warning has been issued. Other areas adjacent to this warning may see up to a quarter of an inch of ice accumulation, while areas within the warning are likely to see greater than a quarter of an inch with isolated areas seeing as much as one-half of an inch of ice accumulation. Portions of extreme northern Iowa, northern Missouri, central Nebraska, and north-central Kansas may also see ice accumulations during the overnight hours with total accumulations nearing a tenth of an inch in locations. Furthermore, some portions of northern Nebraska, southeast South Dakota, and northern Iowa as well as other adjacent areas may see snowfall or other mixed precipitation types as they are expected to remain slightly cooler aloft than other areas; this may lead to an inch or so of snow accumulation as well.

Additional updates may be posted late tonight or more likely earlier tomorrow as the ice storm is well underway. The Des Moines NWS is labeling this as a life threatening ice storm situation, and although the majority of ice may fall during the overnight hours tonight into the morning hours on Wednesday, expect additional freezing drizzle to continue through the night on Wednesday.