An incredibly difficult and challenging forecast is in store for central Indiana over the course of the next 24-36 hours.  I want to get out front with this right from the get go: bust potential is high with this type set-up, as a jog 10-20 miles north or south of the surface low will mean the difference between half a foot of snow and plain cold rain.  As it stands now, and after careful consideration of every piece of data available, here’s our updated snowfall map:

I still am not sure any one piece of data is handling the interaction between the arctic high to the north and the developing low to our southwest “perfectly.”  As such, additional fine tuning will have to take place tonight.  That arctic high is powerful at nearly 1045mb.  From a meteorological standpoint, it’ll be a fascinating battle watching the fight play out.

As you can see, we’re going to be looking at a very tight thermal gradient and it, unfortunately, appears to set itself up directly over the I-70 corridor.  Precipitation type and amounts are the biggest challenge within the I-70 corridor.  Further north, confidence increases rather significantly for a crippling snow storm.  For central Indiana, this will be a very wet and heavy snow event before ending as a drier, powdery snow on the back end.  As winds increase Sunday afternoon/ evening, the heavy “paste” like snow won’t blow around as easily as it would if it was drier.  Further north the snow consistency will be drier and blowing and drifting will be severe (in the 8″-12″+ zone).

In the shorter-term, rain and a wintry mix will arrive into the region as early as early as 6-7 o’clock.

Stay tuned.  Another post will hit here late tonight (midnight-ish).  In the meantime, we’ll keep our thoughts coming at @indywx through the afternoon.