Weekend Update

Wednesday, January 21, 11AM

Yesterday at this time we were hoping that the storm wouldn’t be suppressed south, but model trends through yesterday afternoon and overnight has a lot of people wondering if this is going to end up too far north. I’m in the camp that we are going to see some big adjustments as the players come onto the playing field. The NWS stated in their discussion this morning that they will be sending recon flights over the Pacific where our southern energy is currently located, and that data from those missions will be ingested into tonight’s 0z model runs (midnight, our time). Additionally, the northern stream energy, specifically the arctic high that will be moving across the northern US during the event, is currently located in an area where data sampling is sparse. With that in mind, this will probably not be settled until late tomorrow or even Friday. But, we can still discuss what the models see at this point, but know that we are still early so expect changes.

Just about every model shows snow moving into the area Saturday night and continuing Sunday. The snow is moderate to heavy at times and they all show at least 8″ along the 95 corridor into early afternoon Sunday. They also show that surface temperatures stay well below freezing for all of central MD throughout the event. Where they differ is how much warm air is pulled in at the higher levels that could change the snow to sleet or possibly freezing rain. That is dependent upon how far north the primary low goes to our west as the storm transfers its energy to a coastal storm. The more north, the greater the chance of mixing. I am only guessing but the arctic high pressure to the north should be very strong so I don’t see it getting bullied as much as some models have shown. Not to mention, this is still a La Niña and the phasing and amplifying that we’re seeing right now on the models could be overdone. One other thing that is certain is that whatever falls, it won’t be going anywhere for awhile as temperatures next week look to be frigid for the duration.

I don’t like investing in any one model this far out, but I’m waiting for the midday GFS to run before posting, so for fun, here is what the morning AI EURO (6z) showed. Snow beginning around midnight Saturday/Sunday with a total of 10 – 12″ with temperatures never exceeding the mid 20’s. Some mixing in the afternoon on Sunday, but mainly south and east of 95. I only chose the AI Euro because it’s been fairly consistent from run to run so far.

Anyway the 12z GFS is done and it stopped the north bleeding and has snow starting late Saturday evening and going into Monday morning. Verbatim, there is no mixing issues for areas west of the bay, temperatures never get above about 20 degrees for duration and total accumulations are similar at 10 – 12″.

My takeaway from the runs this morning is that a major winter storm is likely across the mid-Atlantic on Sunday, but there are a lot of details to iron out. If the midday Euro and AIEuro show any drastic changes, I’ll do a brief update, otherwise I will probably wait until after the later evening model runs.