WINTER STORM WARNINGS HOISTED...

Jan 29, 2021

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WARNINGS AND ADVISORIES HOISTED
Winter storm warnings have been issued for most of my area north of I-80 Saturday into Sunday afternoon. South of I-80 to roughly HWY 34 winter weather advisories will go into effect.
Confidence is high on the storm but unfortunately precipitation type is going to be an issue to start as a narrow wedge of warm air gets drawn into the SW third of my area. How far north this actually gets before gradually retreating Saturday night will make a significant impact on potential ice and snow accumulations. I have the official NWS snowfall forecast posted below and you can see the thinking that freezing rain or mixed precip. substantially cuts into snow accumulations in the SW half of the area from Waterloo to Cedar Rapids and on past the Quad Cities.
The latest runs of the EURO and hi-res HRRR (very good and typically reliable models) keep that mild wedge more to the south of I-80. There is a short period where ice or a mix is initially found but evaporative cooling quickly changes that to snow and thus accumulations in Iowa are higher on those models. Compare them  below.

The EURO
The HRRR
We'll need to monitor the trends closely going forward but amounts could be quite a bit higher than the NWS forecast near and north of a line from Kewanee back to Muscatine and to the SW of Iowa City. Northeast of there the dominate form of precipitation will be snow and 4-8" amounts should be widespread. I'm anxious to see what the new EURO and HRRR show with this trend whey they come out later this evening. Of course I will pass that on in a post around 7:00. That's it for now. Roll weather...TS