The pattern for the next 2 weeks will feature a -NAO/+PNA combination, which, for those of you who follow me regularly, know this yields an increased threat of cold and snowy weather for the northern Mid-Atlantic region. Below is the NAO forecast from the 12z run of the European. This is mirrored by the Euro ensembles and the GFS and GFS ensembles from 12z as well. This all points to a very cold period for the next 10-14 days along the East coast.
The storm coming later tonight through tomorrow night is the first in a series of threats during this time period, and will be a moderate event at most, with a general 2-5 inches in the Lehigh Valley, with isolated lollipops of 6 inches above 500 feet in the northern areas. Expect less than half of those numbers, maybe even less, on any primary roads. The Poconos should see 4-8 inches, with perhaps isolated 9 or 10 inch amounts above 2000 feet. South of the PA turnpike, expect rain and/or a mix, and no accumulation. The combination of the increasing March sun angle, marginal surface temperatures, and a relatively fast moving, progressive storm will limit the greatest accumulations to the areas of highest elevation and farthest to the north.
As the NAO becomes stronger and more established, the storm track should be shunted further south, so areas that miss out on the snow this time around will likely see snow later this coming weekend and possibly again around mid week next week.
For those of you wondering how unusual snowstorms are in late March and early April, the answer is, they are, relatively speaking. Looking back over the list of significant snowstorms that have affected the region, the latest and most significant I could find was the March 31 – April 1 1997 storm:
So, given the above, it can happen – and over the next few weeks, it will (although I’m not saying it will be as big as the storm depicted above).
As an aside, I’m planning to expand on the models subpage (with the help of my 8 year old son, who set up the current subpages mind you) to include quick links to both the long range as well as the short range high resolution models for comprehensive one stop shopping so to speak. I’m also going to include additional links to satellite and radar imagery that I’ve collected over the years, as well as other various forecasting tools. Any of the more advanced bloggers from LWB or anyone else who feels they can contirbute for that matter will also be allowed to post on the site. I’m going to try to get things finalized within the next week or two, so stop back for more updates, and enjoy the snow tomorrow, if you happen to be in an area where you see it.