The first winter storm of the season will impact the Mid-Atlantic region on Sunday. Although details of the storm will change a bit over the next thirty-six hours, here are the top five questions about what we can expect from this storm on Sunday and the current thinking:
When will the precipitation begin?
Precipitation will begin in the form of snow in places like Baltimore, Washington, and Annapolis during the early afternoon hours. Temperatures will be in the upper 20s to lower 30s, so the snow will accumulate (although the snow will not be all that heavy.) Secondary roads will become slick and snow-covered. Precipitation will begin earlier to the south, but will be in the form of mixed precipitation.
How much snow will accumulate?
At the moment, an inch or two of snow is possible in Baltimore, Washington, and Annapolis before the precipitation changes to sleet and then freezing rain. Ultimately, the precipitation will change to all rain Sunday night. A brief period of sleet is expected over southern Maryland and the Eastern Shore before changing to all rain Sunday afternoon and evening.
Does this storm have the potential to be an all-snow event?
This scenario is unlikely. As high pressure to our northeast begins to pull away, and as the low intensifies and moves closer to the region, precipitation will change over to sleet and freezing rain, and then all rain by Sunday night. There is an outside chance that slightly more than 1 or 2 inches of snow falls before the changeover. Lately, computer models are suggesting colder air holding firm over the region for a longer period of time, which would result in a bit more snow but, more importantly, a prolonged period of sleet and freezing rain.
How much ice is expected from this system?
The headline for this storm is really not the snow, but the impact of the ice that will accumulate and cause dangerous driving conditions and power outages. This storm has the potential to be a severe ice threat in areas north and west of Baltimore and Washington where freezing rain will snap limbs and bring down power lines. Even areas on the western shore from Baltimore south to Chesapeake Beach could experience moderate icing and dangerous driving conditions through Sunday evening.
What will conditions be like at 6 a.m. on Monday?
Temperatures are expected to rise above freezing by this time in Baltimore, Washington, and Annapolis (and points to the east.) A chilly rain will be falling in these locations. To the north and west, some freezing rain is still likely and driving conditions will be dangerous with temperatures just below freezing.