It could be as early as the 20th. With a TPV this weak the coupling process could be fairly quick. Wrt effects my best guess based on past coupled SSW events is it simply promotes a -NAM state into and probably through the second half of winter. There will undoubtedly be periods of flux but odds are we get at least one more tanking of the AO after this one. I tend to look to other examples where the TPV was a weakling to begin with. Imo there is synergy. Often when we get a season long-NAM state there was a weakened TPV to begin with then a SSW finished it off. And often when we’ve had multiple season -NAM states there was a string of stratospheric weakening events after the main SSW. Interestingly maybe there is a solar minimum (it’s really as the solar begins to increase after the min) link. If we take the whole of the late winter 2009 when the first major SSW hit through 2011 period you could argue we didn’t even maximize potential. Even just 2010 it wasn’t non stop snow even though the -AO/NAO ran pretty much straight through the winter. We did miss a few threats. I think while getting cold/snow in general is getting harder odds of anomalous extreme snowstorms or periods (if you can string a couple together) have increased due to the increased baroclinicity and energy available due to warning. I don’t think it’s a coincidence that in 90 years of records I poured through before 1980 I only found 3 20” storms up here...but there have been 8 in the 40 years since and even within that span the frequency is increasing with 5 in the last 12 years.