All the data has been showing a storm that will impact our region late in the day on Wednesday, but the locations that would be impacted has been somewhat fuzzy in the computer models. Today, they are zero'ing on what I would call a more accurate solution, so I want to discuss who could see the wintry mix and when in tonight's blog.
Wednesday Night Wintry Mix
The amounts of snow falling in each computer model is slightly different, but all show a storm that will move across southern KY Wednesday night. While there are subtle variations, they all do show this storm. The NAM shows the disturbance late Wednesday well.
We have seen a trend to put the heaviest of the precipitation in southern KY late Wednesday, but that is also the area that will be the warmest. It has been clear from the start that this storm would fight low level warmth and that continues show up in all the data. I think this mitigates the chances that the storm on Wednesday night will be of significance. AdvanceTrak brings in the precipitation after about 7 pm and then lingers flurries through early on Thanksgiving. As you look, note the timestamp on the top right part of each image.
Computer Model Snowfall Output
I get asked a lot how I know which computer model snowfall output is legit. I will tell you that all snowfall output uses a simple algorithm. When a computer model says the precipitation type is snow, then it converts the amount of liquid that falls to snow at a 10:1 ratio. This means the EURO and GFS (which have poor low level resolution) will produce horrible snow predictions when there is any mixing involved. The data should thrown out the window anywhere there is mix involved. It amazes me over and over how I see people looking at the EURO and GFS as legitimate data when there is a mix involved because of this error that is always built into the data. With that in mind, we know mix is involved in this storm, so we would expect the NAM to be the most accurate.
GFS Snowfall Totals For Wednesday Night
EURO Snowfall Totals For Wednesday Night
NAM Snowfall Totals For Wednesday Night
AdvanceTrak Snowfall Totals For Wednesday Night
My Thoughts On The Storm Late Wednesday
Through the day today, we have seen a slight southward drift in the track of the low on all the computer models. There is still a slight variation in the data , but the general consensus is the low will move across southern KY late on Wednesday. The precipitation should start around 7 - 10 pm west of I-65 in our KY counties and spread across the rest of our KY counties by midnight. The data does suggest only light amounts will fall in southern IN but it would be late evening when it falls... if it does.
To be honest, I don't see this is as much of a snow maker. The low levels are well above freezing for the duration of the storm system on Wednesday. Obviously a warm surface would not hold much snow, but warm pavement even makes it more difficult. Notice the pavement temperatures are WELL above freezing right now and should continue to be through early Thursday when this system departs.
The bottom line is that is not a setup that supports much snow accumulation. If we are to see any light accumulations, it will likely occur south of the river from around Brandenburg, KY to E-town, KY to around Springfield, KY. The data does suggest that moderate mix/snow bands could develop in this area. A grassy 1/2" to 1" accumulation is possible in these locations, but I do think it would melt pretty quickly with the temperatures in the mid 30s.
We will obviously be watching the storm closely, but as it stands nothing suggests any major problems on Wednesday night. A few slick spots are possible, but not much more than that.
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