While we are dry for the first half of the weekend (today), things start to change in a big way starting tomorrow morning.
A low pressure to our South will bring in moisture as temperatures are right around freezing. Notice I said right around freezing...not everyone below freezing. Air temperatures as this moisture moves into the area will really be the deciding factor on what mode of precipitation falls depending on where you are.
Moisture will begin to move into the area early tomorrow morning. Most models are moving a mix of snow, sleet, and rain into the area between 4-6am. Temperatures will be hovering very close to freezing around that time frame.
Model data is beginning to hone down on who is more likely to see all snow, who is more likely to see a mix, and who is likely to see all rain.
As the system moves in, it becomes more apparent that our Indiana counties have the greatest likelihood of seeing an all-snow scenario with temperatures right at and just below freezing all the way down to the surface.
The dividing line seems to be right around the Ohio River area. The further South you head of the river and the further South you go into our Kentucky counties, the less likelihood of seeing an all-snow event.
Louisville will be caught in the middle and should see a good mix of sleet and snow at times by tomorrow morning and into early afternoon.
Something to keep in mind is the possibility of what is called dynamic cooling. Some data shows a little more intensity on how hard the precipitation is falling just on the other side of the river. If this were to occur, we could see dynamic cooling take place. What that means is that when snow is falling at a higher rate, the below freezing temperatures higher in the atmosphere (where the snow is actually forming) gets pushed further to the surface and could cause temperatures closer to the ground to drop. If this were to happen, then more of an all-snow scenario would be likely for Louisville.
Most of the moisture will move out of our area by late afternoon on our Sunday, leaving accumulations on the ground for some. So, let's try and dive into the tough forecast in terms of accumulation numbers.
It's important to keep in mind your expectations when you see snow totals, that the lower number on the range is also a possibility, so try not to focus too much on the higher amount.
Again, like we said, the greatest chance of seeing snow accumulation is our Indiana counties. Temperatures will have to be below freezing from where the snowflakes form up above our heads, all the way down to the surface. So, the white shading on the map below, including all of our Indiana counties and right along the river and part of Louisville is in the 0.5" to 2" of snow range.
The darker and gray shading that includes South Louisville down to E-Town is the range of 0" to 1" of snow accumulation.
Again, try not to focus on the higher number if you're included in one of those shaded areas, as anywhere from that lowest number to the highest is possible. The true test on what will be falling from the sky by tomorrow morning will be dependent on whether the temperature over your location is above or below freezing.