No doubt we will have a challenging 17 hours ahead in our weather...
Tonight/Pre-dawn Thursday/Thursday night: Mix to rain to light snow
Sunday night: Light rain may end as brief light snow
11/27: Turning colder. Rain to snow setup potential.
We have an Alert Day out for this evening into Thursday as an early season winter storm moves into the Ohio Valley.
Let’s start with the timeline
Now-6pm: Moisture increases from the south. Some light snow flurries/sleet/sprinkles may develop later with no issues.
6pm-8pm: Burst of sleet/snow in our southern counties that will transition to more of a rain/freezing rain mix. Mainly dry north of I-64 for this period.
8pm-4am: This will be the main event. Burst of sleet and snow will continue to move north into southern Indiana with light accumulations possible. Including Louisville. Roads are expected to be just wet for the start of this but that changes after 11pm with colder air pushing areas along/north of I-64 to the freezing mark if not a tad below. Warmer winds aloft allow for anything frozen falling to become rain...freezing on contact, aka freezing rain. This looks to impact elevated objects the most. This would include power-lines, trees, bridges, cars, overpasses, etc. Treated main roads will have the warmer ground in their favor along with the salt. Heavier rates would mean the trucks would have to do several passes to keep it from washing off. Side roads would be more at risk for some ice to form but even there, it looks limited. Driveways and porches run a bigger risk so be careful walking to the car and keep the ice scraper OUT of the car tonight! The best potential for icing would be roughly along the Ohio River and north. Less amounts/duration south. I will caution that the exceptions would be the valleys (like in Meade/Hardin Counties) where cold air may get trapped near freezing a bit longer and therefore a bit more icing.
4am-7am: Dry punch of air works in from the southwest. This will start to shut off the precipitation and also allow for most, if not all, locations to warm above the freezing mark. This would be good news for the commute if timing/trends hold.
7am-5pm : Spotty light rain. Temps in the 30s and 40s.
5pm-11pm: Backlash snow showers/flurries possible. Minor accumulations could take place for some.
This is a very temperature sensitive forecast. A few degrees + or - expectations and we get a completely different outcome. Good or bad. With ice, let’s certainly hope the good in that the models are too cold and we end up warmer than expected. No one can drive on ice.
I will also mention for those of you in Indiana that the duration of the cold layer still has the risk to linger longer than the data shows. This means you could run the risk of a quick 1-2″ snowfall before the mix/transition. Something to monitor.
Overall, this isn’t a major event with timing favoring the less traveled times, but is has been nearly 30 years since we have had freezing rain in our area IN NOVEMBER so there isn’t great historical context to use here. It will be very important to stay close to the forecast updates as there will be many!