Continuing the theme of late autumn and now into met winter, patience is going to be required.
What we are seeing on the ens is a mix of variability and 'unicorn' pattern morphing in the LR. While the NAO is still likely to develop and has already begun to do so, we are seeing changes up top as well as increased flex in the SER in the medium range. The weaker and quick-to-fade TPV that last week's ens were showing as a bowling ball setting up over Hudson Bay is one of the key players that is throwing fits at winter wx freaks. A strong TPV over HB can help knock down a SER and we sort of rely on this during a Nina. Without this (and other pieces) the SER can continue to bulge and remain a base state wrt a Nina pattern.
Couple this with a strongly retrograding NAO ridge and this often times leads to a link between these 2 features putting things on 'hold' until a catalyst comes along to help out. This could be a PNA ridge, a TPV building S near HB, or a favorable MJO phase (which ties in the PNA).
As noted before Thanksgiving, that pig ridge in the PAC that keeps feeding a ridge over the Aleutians isnt going to make many friends....though at times it CAN feed the EPO which bumps the TPV into more of a favorable position. However, this can also lead to cold and dry episodes. So, it is a real balancing act we try to work with during Ninas.
What we are seeing on the GEFS is more of a move towards SER/NAO interaction, transient PNA ridging, a split flow off the WC with stj connection, weakned TPV, and more robust central PAC blob ridge.
Needless to say, this isnt a be all-end all deal. There is plenty of support for the -NAO/-AO hanging strong. And this bodes well as we get deeper into winter. Without those HL ridges as a base state this winter, we would probably be shutting the blinds for chunks at a time. BUT, if the HL blocking continues as a background phase, then we will be able to have chances as this balances out the less favorable teleconnections.
Long-winded and probably not the clearest or most well-worded writeup, but a few points.....dont chase unicorn patterns particularly in a Nina in the LR, temper expectations even when good looks begin to show in the MR, and be patient. I cannot emphasize that last one enough. We usually need to wait for the NAO to relax/reload to score and even then, it isnt a lock. Cant tell you how many times we've seen good patterns come and go with little or nothing to show. But with that said, if the NAO/AO continue to reload this winter, the odds if cashing in will increase. Going to take some time and a little (lot?) of luck.