Thursday, January 9, 2025 4 :30 P.M.

While we’re still cleaning up from Sunday’s storm, another one looms on the western horizon. No concerns this time with sleet and freezing rain, so it simplifies the forecast somewhat – just snow. That primary question still remains…how much? I’m hopeful I’ll do better this time.

We’re dealing with a similar system again. A large pocket of energy has dropped south of the main jet stream over the western U.S. These so-called “cut off lows” usually drift slowly eastward and eventually rejoin the primary flow. Since they migrate from the southwest, they have a good source of moisture available when they cross the southern Rockies and head northeast – as we saw last weekend.

Luckily, there are some differences this time. 1). Last week’s storm dragged a huge mound of cold air into the area east of the Rockies. 2). That cold mound will force the new system to stay south -mainly along the Gulf Coast. 3). That will keep the primary moisture energy fields from reaching this far north. 4). The primary axis of the jet stream flow with this system will be from northeast to southwest. This situation is called a positive tilt trough. Positive troughs have much less energy to use than negative ones.

This system will still produce an area of snow/sleet/freezing rain, but this time the focus will be across parts of Texas and Arkansas at first, then move east over Tennessee and the northern parts of the Gulf Coastal states.

We’ll be on the northern side of the system and will be in an area of classic “overrunning.” Some warmer, moist air will be slowly gliding over the colder air mass we’re in. The result will be about 8-10 hours of slowly accumulating light snow. Snow should begin shortly after Noon and wrap up before Midnight. I expect Louisville to have a 2″ to 4″ accumulation (less on highways). Snow accumulations will be lower north of I-64; slightly higher south of the Interstate.