Our region’s first winter storm in nearly two years is set to bring widespread heavy snow, sleet, and cold temperatures to the region! The forecast has come into better focus over the last 12-18 hours, allowing for some uncertainties to be ironed out. But, a few questions do remain!
Alerts: Yesterday, Winter Storm WARNINGS (shaded in pink) were issued for much of the Mid-Atlantic. Widespread heavy snow is likely to cause high impacts. Areas south of DC could also create high impacts. Winter Weather ADVISORIES (shaded in purple) were issued for Southern PA, where lighter, but still impactful, snow will fall. The alerts all run from late tonight through early Tuesday morning.
Our Cedar Point Federal Credit Union Futureview model agrees with the ideas that have been sharing the last several days. That is, the heaviest snows with this system are likely to fall along and just north of the DC corridor.
Timing: We will see periods of snow begin to move into the region as we approach midnight tonight. Widespread snow, some moderate to heavy, is possible between midnight and sunrise. We will then see the sleet/mix line move northward in Southern MD and central VA. A period of snow mixing with sleet is possible through the mid-afternoon hours. A lull in the action with lighter precip and dry pockets looks likely midday Monday and afternoon. Very little may fall during this time. However, backend snow looks to develop as we approach sunset Monday, likely lingering through midnight.
Snow Accumulation: My final call on snowfall continues to favor areas through northern Maryland to see the highest snow totals. Up to 6-10″+ of mainly snow is likely there. A general 4-8″ is possible south of there, where sleet will cut into totals. More sleet = lower the snow totals. Lesser amounts to the north, where there is likely to be a lack of moisture. However, any northward jog could increase totals in Southern PA… potentially by a couple of inches!
Ice Accumulation: Freezing rain and sleet will be possible south of DC from the mid-morning to early-afternoon hours on Monday. This could accumulate up to a tenth of an inch of ice glaze in Southern MD. More ice is expected in the southern Shenandoah Valley, potentially up to half an inch of ice.
Locally in Southern Maryland, the highest totals will be found north of the Benedict-Prince Frederick bridge. 5-8″ of snow seems likely in our northern communities where sleet is likely to mix in for only a couple of hours. Slightly lower totals of 4-7″ are likely south of there thanks to increased warming and mixing. The far southern tip of St. Mary’s County and the Northern Neck are likely looking at 3-5″ of snow as mixing issues begin earlier and linger longer.
In terms of schools, many districts throughout the Mid-Atlantic are likely to be closed on Monday. Even to the north where lighter totals will be found, snow will persist throughout the day, potentially heavy at times, causing adverse travel conditions. These impacts are likely to linger into Tuesday as well. I will have an updated forecast for Tuesday’s School Odds out tomorrow.
Storm FAQs
How confident are you in your forecast? My confidence in this forecast is high. For the last several days I have favored a track that focuses the highest snow north of DC. Our models are now beginning to show there. However, there are a few outstanding questions regarding how far north the sleet line gets, how dry the air is north of Baltimore, and where exactly the heaviest band of snow could set up. I detail all of these lingering questions more in my evening post from yesterday, which is linked below.
Where will the heaviest snow fall? The highest totals look likely to be concentrated just north of DC through Northern MD and Northern VA. These are historically favored in situations like these. Some communities in this small area may even see localized 10″+ amounts if the bands of heavy snow set up just right.
When will the snow start? Current guidance shows that the snow may begin late Sunday night, likely between 9pm – 1am.
How much snow will have fallen when I wake up? Likely 2-4″ of snow will fall area wide tonight. You will add more to that north of DC through the morning. Everyone will add an extra couple of inches Monday with backend snow.
When will the heaviest snow fall? Probably during the early morning hours around sunrise. Heavy snow could longer into the late-morning hours north of DC.
When will the snow end? The initial band of snow tonight likely begins to shut off by midday Monday. However, the storm looks last into Monday night thanks to a second round of back end snow.
How much snow will I get at my house? Check out the accumulation map. Generally, I’m expecting 6-10″ near/just north of DC, 4-8″ for most of Southern MD, with lower totals across southern Calvert and southern St. Mary’s (thanks to sleet) and north of Baltimore (thanks to lighter precip rates).
Could more or less snow fall than currently forecast? Absolutely. In order for even more snow to happen, we would need to see heavy snow bands develop right over Southern MD. Colder temperatures would also lead to more snow, as opposed to sleet, for southern zones. On the other hand, if the storm takes a slight jog to the north, or if the air is not as cold, many areas will struggle. In light of these plausible scenarios, here’s my assessment of snowfall probabilities:
10% chance: 1-3″
25% chance: 3-5″
50% chance: 4-8″
15% chance: 6-10″+
As you can see, we have at least a 65% chance of seeing 4″ of snow across the region. However, there are also chances for this storm to boom or bust.
Any chance of a wintry mix of freezing rain or sleet? Periods of sleet and freezing rain will be likely during the midday hours of Monday.
What impacts can I expect? Generally speaking, expecting widespread and high impacts on Monday. Schools are likely to close, and roads will be snow-covered. I would expect these impacts to linger into Tuesday, especially where the heaviest snow falls.
Closing Thoughts: All in all, widespread impacts are likely from heavy snow and sleet on Monday. While there are sure to be some surprises throughout the storm (as there always are), such as where a heavy snow band develops, I feel confident with this forecast. Make sure you finish all preparations today. I will be here throughout the storm to cover its impacts! Stay tuned!
Stay with JB Weather for the latest information on impacts here in Southern Maryland and across the Mid-Atlantic. You can always access my forecasts and updates here on the website, on Facebook, on Twitter, on Instagram, and on YouTube. JB Weather is the Mid-Atlantic’s Weather Leader, and I am working around the clock to keep you ahead of any storm!
