EastonSN+

For what it's worth the euro and the gefs now are in general alignment on the mjo. Both stay very weak in phase 8 and have a small spike in phase 1. I believe a couple of METS said the mjo is likely having very little influence on the weather pattern. This is likely true as we saw a couple cold outbreaks in December when the mjo were in warm phases.

Likely a Miller b that gets cut off and lingers rather than what it's showing.

GFS with a really strange storm evolution.

The first wave is a nice little snow storm for North Carolina LOL.

It's good to see the 540 line all the way down to Norfolk.

That's lobe in Canada is pressing South at the same time which can hinder the storm from cutting.

The EPs and gefs are in line with the blocking and the Pacific region. The one difference is the mjo where the gefs is very weak in phase 8 and then strengthens in phase 1 while the euro is much more amplified in phase 8.

Another factor that I am unfamiliar with is wave spacing and how this may come into play obviously the more space between waves the better chance for amplification.

Ironically we need more of a Southeast ridge which can be done through more of a Southwest development and negative tilt.

Thanks for this Don, one interesting factor to monitor are the high temperatures on the East Coast and how this may increase the intensity of a storm off the coast in a similar way that hurricanes have been stronger due to the warmer ocean temps. This leads to your earlier post on potential declining snowfall totals for our region and how stronger more intense storms may slow the average snowfall averages decline. Another advantage that we hold in addition to latitude over the DC area is that our region is in a better position for Miller B's where the DC region is more reliant on Miller A's.

Completely oversimplifying, however, the stronger the first wave is on the modeling the more weakened and suppressed the second wave is and what we have seen so far on the 12z guidance so far. That being said, the initial wave could trend stronger and still give us a heavy snow storm.

Gefs keeps the trough in the East right to the end.

Lots of potential here for sure, and potentially multiple events.

Great post, as long as there is a cold source to the north to tap into it can snow in warmer temperatures in January and February with the right track.

It's more that this is a 1980s setup where the trough is positioned a bit too far east, a decade ago it was all EPO driven and the EPO was East based which is rare.

Does anyone know where to find the EPO index. In the Middle Atlantic forum a few days ago they showed a chart which showed the EPO tanking and the PDO rising.

If we can get the gefs to spike the PNA like the Euro does we can have a really really big storm. Regardless even with the muted PNA Spike on the gefs we are definitely getting a long period of cold and some chances of snow. Win win just pointing out the minor differences.

Slight difference between the euro and the gefs. Euro is higher amplitude and phase 8 which is what we want.

Just for illustration, however it's been a couple years since the Middle Atlantic and Southeast had a major snowstorm this type of massive cold air intrusion is the perfect setup.

If I am not mistaken this would likely mean a storm track which would favor a Southeast slider, which is what the GFS is showing. Fast flow does not allow the storm to gain latitude. That being said it would be rather interesting to see a Southeast slider in a la niña.

12 inches is a very high amount for an ensemble mean.

January looks chilly at least the first couple weeks. Wonder when the last time we had back to back below average temperature months.

The 1990s were the All or nothing home run hitters of the winter decades.

Finally getting a decent amplitude passage through 8 1 and 2. Warming Waters in the Indian Ocean will help with phase 1 and 2 amplification.