Friday Update

Friday, January 23, 12:30 PM

The global models have stopped the north bleeding since I last posted yesterday, and if anything, they are trending slightly south and with a colder profile. We are still too far out to rely heavily on the mesoscale (short range) models, and until the globals come to a consensus, I don’t see any reason to change much from yesterday’s post. In summary, the NWS has issued Winter Storm Warnings early this morning for all of MD west of the bay for Saturday night into Monday morning. Arctic air is arriving today and there are also Cold Weather Advisories for dangerous wind chills tonight through early next week. Regarding the storm, and this is still preliminary, but snow will develop from southwest to northeast across MD from 10PM to 1AM tomorrow night. The snow will initially be light but will pick up in intensity and be moderate to heavy by sunrise. Heavy snow will continue during the morning, but a warm layer will begin working in from the south and east, and snow will transition to a mix of snow and sleet, and even all sleet in many areas. It’s too early to know when that happens, but I still feel that 6-9″ of snow accumulation for areas along the bay to just west of I-95 respectively, before the changeover. For the normally colder western and northern counties west of Route 32 and north of I-70, 8 – 14″ of snow before any changeover, if at all. By Sunday evening, colder air will begin wrapping into the system’s higher levels and we will have to see if there is a changeover back to snow with additional accumulations. The accumulations that I stated are initial thoughts for what I think that accumulate before the changeover. We can save any talk about any possible additional snow accumulations Sunday night until tomorrow. Also, although the NWS defines sleet as snowfall, I am talking about just snow. Some areas are going to be measuring sleet in inches, so regardless of whether your area changes to sleet, this is going to be a very impactful storm well beyond Sunday. Sleet over snow with the frigid temperatures is going to make for a glacier. The good news is that right now freezing rain does not appear to be a major concern for most of central MD as the depth of the cold should be able to overcome a narrow warm layer. The exception is for readers in south and east areas including lower AA, Calvert, and especially St. Mary’s counties as icing could be substantial in some of those areas.

I’ll update later today if there are any substantial changes. If not, assume no changes, and I’ll send out something tomorrow morning. And finally, never trust snow accumulations on a phone’s weather app.