We have entered into one of the most consistent periods of cold we have seen in some time. This should easily take us into the MLK weekend time frame before we begin to see a pattern change. The Euro ensemble 2m temperature (F) anomaly shows below normal conditions in all areas outside of extreme northern Maine. Great news to make snow, but not a lot in terms of natural.
From a broad point of view, we have just started to see the equatorial Pacific enter La Niña conditions. The ONI for October/November/December was -0.4, which is still technically neutral. The last three weeks have featured anomalies in the weak La Niña range, therefore depending on how long this lasts will tell if we actually get into La Niña or simply flirt with it. However, hovering around it won’t make much difference in our overall pattern at this point. Minimal movements in the ENSO cycle are our friend in winter.
Nonetheless, we are heading into a pattern that is fairly quiet and cold, with regional influences making their impact, especially with upslope snows. That will be the main source of precipitation through the next 10 days or so for areas north of the Poconos/Catskills. The Mid-Atlantic is preparing for a moderate to heavy snowfall on Monday — a system shunted to the south because of the dominant high pressure over New England. This could be the biggest widespread snow since the infamous Snowmaggedon snow in the 09-10 season, which I lived in Harrisonburg, Virginia for (and promptly moved to Maine after the following winter brought about 10″ total all season). Southern PA/MD/WV/VA resorts, this one’s for you!
Models are trying to create some weak low pressure systems around 1/12 and again 1/16, but right now the cold still seems to be too strong to allow much to form. The NAO stays strongly negative through about 1/18-19 and then eases, which means if we’re going to see the ability for coastal storms (and to stay snow), it’s probably the week of MLK Day.