The November CPI report encompasses two months and also includes some unusual seasonal or data collection factors. That's going to make the 'cleaner' read as the y/y numbers, which are expected at 3.0% on both the headline and core.
The BLS posted an FAQ yesterday about lack of October data collection and the trials of data collection because of the shutdown. Officials started November collection on Nov 14, compressing the window and that will create some sampling noise.
Notably, collection started much closer to Black Friday, which could bias goods inflation lower.
