Major ice storm in progress...

Moderate to heavy snows and on-going freezing rain and sleet continue to fall over the Lower Ohio Valley early this morning. While the snowfall is significant, the amount of icing is most impressive with this large system pushing east-northeast. The latest radar from Indianapolis (to the right) clearly shows the enhanced reflectivities with the freezing rain and sleet over southern and eastern Indiana.

The higher reflectivities result from two processes... First, from the radar beam reflecting off frozen precipitation particles. Secondly, from the radar beam being reflected off melting nuclei (ice particles melting at the point where ice pellets aloft are entering the shallow warm-layer between roughly 850 and 800 mb. RUC forecast soundings late last night were fairly indicative of the shallow warm layer. The NAM and GFS were both overestimating the thickness of the layer, thusly had much more freezing rain than sleet (there's been plenty of reports of sleet throughout the Ohio Valley tonight) and had it more southeast. Luckily, I found this out before leaving my forecast behind at the end of my shift tonight.

Either way, this will be one of the nastiest ice storms in quite some time over portions of the Missouri, Tennessee, and Ohio Valley's. I didn't get around to it last night at work, but if I think about it, I'll post some of the observations we saw tonight from Southern Missouri and Northern Arkansas with this system. We saw a few different stations that had well over an inch of ice and one site, in particular, that received 0.43 inches of freezing rain in one hour! Pretty incredible. I also read an LSR (local storm report) earlier tonight of a report of 2 inches of ice in Fox, Arkansas! Now that is a crap-load of ice!

The shocking thing, this storm is long from over... Precipitation likely won't pull entirely out of Indiana until this afternoon and I could easily see several more hours of freezing rain and sleet over far southern and southeastern Indiana. There have already been numerous reports of 3/4" of ice already in these areas and with several more hours of rates like this, these locations will also likely see ice accruals of more than an inch. Of which, would result in power outages and widespread damage to trees and power lines.

The web-cams will be interesting to watch later this morning as dawn breaks. Assuming they, themselves, won't be covered in two inches of ice!

And to see the extent of this system, take a look at the NWS Advisories graphic in the sidebar to the right. Unbelievable how widespread the Warnings are. From Ice Storm Warnings in Texas to Winter Storm Warnings in Northern Maine!