The presence of a third sudden stratospheric warming after a significant warming that ended several days ago and an incredible ongoing SSW (link) would surely penetrate the inner core of the polar vortex, pushing it further and further to the breaking point, a.k.a. collapse. I have been heralding such a collapse for weeks now, and I am not backing down with its potential. While the collapse may be pushed back a bit, I am confident that a collapse (the Arctic Circle is no longer dominated by the polar vortex) is imminent in at least some parts of the stratosphere.
Let's turn our attention to the next potential Fourth SSW. This one has me very excited, because it could feature a prolonged warming event, which would only further enhance the vortex's collapse, possibly into oblivion if we're lucky, keyword "if".
Phases 2, 3: 25-36 Days
Phases 4, 6, 7: 13-24 Days
Phase 7, 8: 12 Days
So, if we use that MJO forecast graphic, we see the models going from Phase 5 to Phase 7, which is roughly a 13-24 day lag time from MJO phase to SSW. But here's the catch: the models start to circle in Phases 6 to 7, meaning the convection in the image on the left stays in the areas just east (and inside) of Micronesia. What this ALSO means is the potential for a prolonged stratospheric warming event starting in the next 13-24 days and continuing for as many days as the MJO can stay in the designated Phases.
This is all very exciting, but a major caveat is that the MJO does not necessarily always provoke sudden stratospheric warmings- it helps them along, so to speak. In this environment, an SSW would be easy to establish.