I somehow missed this last year why Glenn abandoned his winter forecast. I knew he didn't release a forecast but didn't know exactly why...
"I have determined these forecasts to have marginal what we call “skill.” Skill is anything better than flipping a coin. There’s no reason to do them at this point other than public demand. I’ve always said that if it ever got to the point where I didn’t feel the confidence to be able to do it with skill, then I would ask: Why are we doing it? We used to do them with skill."
https://www.phillymag.com/news/2020/12/07/philadelphia-winter-forecast-hurricane-schwartz/