Updated Friday at 5:00 PM..... The 18Z NAM has increased the precip. total for Louisville to over .50 inches which if it is all snow, it would be over 5 inches.
The 18Z also cools the air aloft faster so most if not all of the precip. will be frozen.
The Rapid Refresh model splits the heavier precip. areas to the SE and NW of Louisville.
Still, most of the precip. will fall as snow as it is also cooling things off faster by an hour or two which can make a big difference with this system. This model would still give Louisville over 3 inches of snow.
New updates from the NWS offices....
NWS Louisville has some concerns about a warm layer aloft....Recent ACARS soundings out of KSDF this afternoon also reveal a 3000ft thick layer of warm air centered around 850-800 hPa. The main and critical forecast issue is how far north will this low-level warm layer will get...as it will ultimately determine precipitation type and modulate accumulations. Current thinking is that that it should likely make northward progress to just north of the Ohio River this evening.
Given the current data, a swath of 3-5 inches with isolated amounts of 6+ inches is likely along and north of the Ohio River. A very pronounced gradient is likely to develop somewhere along the river.
A general 2-4 inch swath along and just south of the Ohio River which would include metro Louisville. This swath will likely edge eastward down the I-64 corridor. As mentioned earlier, this forecast is subject to change and snow amounts may need adjustment based on how far north the warm layer advances. Thus, we will continue to monitor observations this evening and adjust the forecast as required.
The 18Z and later models so far have shown that the cold air will build in faster and the moisture content will be higher. More updates this evening as to where the heaviest snow may go. In southeast Missouri, a mix of sleet and snow is falling.
AccuWeather has up to 3 inches for Louisville with locally higher amounts just northeast of Louisville up to Cincinnati.
current NWS snow forecasts......
Bowling Green up to 1