Friday January 13 – A Winter Weather Advisory has been put in place from midnight until Saturday afternoon for much of central Maryland, southern Pennsylvania, and parts of northern Virginia. I don’t want to get lost in the specifics of timing, but I do want to quickly shed some light on a few things. First, these small events can be trickier than a big storm. This will be on the light side (an inch or so), and falling on roads that just had two very warm days. Temps tonight could stay near or above freezing by you, then drop below 32°F as the develop snow will generate its own cold air. The most tricky part of this will be 7 to 10 AM Saturday morning. Below is the latest simulated radar and wider view plot for the Saturday event. I don’t want to stay storm since it will be light. But it will impact some travel on yet another Saturday. I will have my final call for snowfall in my evening post.
- Cecil County and Delmarva? This is not ‘missing’ or ignored. It is a problem with multiple National Weather Service Offices that cover different parts of our region. The NWS Office in Philly/Mount Holly covers this area and often they act on a later schedule with advisories than the Baltimore/Washington office. #coordinationpolease
- Atmospheric Memory – This will be the 3rd Saturday this winter we have had to deal with a winter event. Sometime the pattern just works out like that. I know it is a waste if you want off of school. But a pain if you have events planned. My son has a basketball game and I hope he gets to play. That all depends on how the road crews can handle this event.
- Bias/Trend North – Much like the rest of this winter and the recent snow events I tracked… The front responsible for this weekend’s snow or mix will not end up as far south as earlier thought. My snow map this morning was a reflection of anticipating that. So I placed snow north of many models… But the actual system may verify even farther north.
- Front stalling sooner – The precipitation can send some moisture earlier… so the risk of showers overnight is a lot sooner than the onset map I showed this morning. I still think the main bulk of this system will behave along that timeline… I will post that below.