Under the Low: Appy Snow, T-Storms

One unique thing about being underneath an upper-level low pressure system is something called "instability showers." This means that, as the sun warms the earth during the day, the atmosphere is unstable enough to produce clouds and individual, cellular showers. Below is the 500mb chart from last night (not unlike a surface pressure chart, closed lines mean areas of low or high pressure), showing the upper-level low in Michigan. It will move southeast over the next 36 hours.

This precipitation can come in the form of rain, snow, or even thunderstorms with small hail as Henry (PREMIUM | PRO) alludes to (and with temperatures in the 30s and 40s, it can be very difficult to tell sleet from snow, if you didn't know that these were instability storms). I've pasted a shot of the 4-KM WRF below showing accumulated snow over the South, but use it with caution; Frank (PREMIUM | PRO) has a detailed video blog explaining the chances of snow tonight across the Southeast.