Initial Thoughts for Thursday Morning

There’s nothing like starting off the winter season with a storm that has 4 different models showing 4 different solutions, but that’s really just par for the course in this area.

The easier forecasts for tomorrow are west of the I-270 and Route 15 corridor and along the northern tier of MD and PA where a prolonged period of mixed snow, sleet, and freezing rain could make travel difficult well into the afternoon.  Also pretty easy is the areas east of I-95 into Anne Arundel, most of PG, Calvert, and the eastern shore where temperatures are expected to be above freezing so even if the precip starts as something frozen, the transition to rain should be quick.  The problem forecast is for central MD between Baltimore and Washington especially as you go west from 95 including Montgomery, Howard, northern Baltimore, Harford, and any counties west.  Depending on your model of choice, we could start as rain, freezing rain, sleet, or even a little thump of snow, all of which is complicated by an expected start time of between 6 and 8 AM.

Right now for central MD, I think we will see a period of frozen precip during the morning and be in the form of sleet with maybe an initial burst of snow.  Start time around 6AM near DC and working north to about 8AM near the PA line.  Temperatures should rise to above freezing by late morning and the sleet will change to rain.  If poor conditions do develop tomorrow, the greatest threat is during the mid and late morning as the precip gets steadier and cold air remains entrenched at the surface.  By afternoon, most areas along the 95 corridor should get above freezing, but western and northern areas will hold on to cold temperatures longer.

As far as school schedules, it may come down to the onset time and whether schools can start before things get messy, and then head home in the afternoon when things have improved.  Unfortunately, in situations like this storm where warm air moves over cold air, precip can start earlier than medium range models suggest, so short range models need to be checked right up to the onset.

As I finish writing this, the NWS has issued Winter Weather Advisories for all central and northern MD counties from the bay to the Blue Ridge for 7AM to 4PM tomorrow, and a Winter Storm Warning for areas west of the Blue Ridge.  I’ll update later tonight or first thing tomorrow regarding what the short range models suggest regarding start time and type of precipitation.