The recurrence interval for these type situations is quite low. Deep/persistent/intense mesocyclone, limited near-term potential for storm mode change, and very broad downstream warm sector with dangerous parameter space.

We had 0.4" of snow and 0.04" of liquid at IND, and the resulting travel impacts from this unexpected low-end event were significant. We're meeting with DOT partners tomorrow for an after-action review to learn more about road surface temperature and road treatment challenges.

Up until late morning/midday model updates, ensembles were under-dispersed and clustered with meaningful QPF to the southwest of Indianapolis. Although I don't have ensemble data to show, you can see the trend in the ECMWF QPF here. This was seen in other models as well.

Here is a quick example of just how challenging low-end wintry precipitation events are to forecast, and how impactful they can be. On 12/2, a midlevel shortwave trough trended in the models to be more amplified and stronger the morning-of, which we reacted to.