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2018

Winter Storm Threat: April 2 (Only/Final Call)

Almost didn’t make a snow map for this event, but I like the novelty of an April snow. At least most of the snow will fall during the early AM hours on the 2nd, so there won’t be much of the Sun’s rays to kill the rates in the Mid-Atlantic. However, precipitation starts as rain south of the 40N line, and is all rain by the time you get to D.C. and points south. Surface wet-bulb temperatures will be above freezing within the southern edge of the 2″ or less zone, which along with warm ground temperatures will drastically cut into snow totals.

I would certainly think that risks run toward getting less snowfall than forecast rather than getting more. I could see a few spots on the southern edge getting more, especially in the higher elevations, if rates can be really heavy for a few hours.

Winter Storm Threat: March 20-21 (Only/Final Call)

Lots of uncertainty with this setup given that 1) surface temperatures are marginal, 2) mixed precipitation could greatly reduce snow/sleet totals depending on how far north+west the mixing line goes, 3) precipitation rates fighting daytime sun both Tuesday and Wednesday, 4) it’s actually two waves creating snow Tuesday night through Wednesday.

There’s going to be a lot of variability, but the corridor of 4-8″+ has the highest confidence based on the factors listed above. Anyone in the less than 4″ contours could see notable local variances based on elevation and where the best snow bands set up both Tuesday and Wednesday. Tuesday will be more elevation dependent than Wednesday, and banding will be the more significant factor Tuesday night into Wednesday.

Winter Storm Threat: February 17-18 (Only/Final Call)

A nail-biter between warming low-to-mid level air and marginal temperatures/wet bulbs at the surface. At least the Sun won’t be fighting most people during most of this event from D.C. northeastward.

Biggest uncertainty lies with snowfall rates, especially in areas that have marginal wet bulb temperatures at or above freezing (i.e. anywhere south of the Frederick, MD to Philadelphia line, generally speaking). That wet bulb freezing line has also been creeping further north than what I had anticipated when looking at the setup over the past few days. We’ll see it the wet bulb temperature or the snow/sleet rates win.

Winter Storm Threat: January 3-4 (Only/Final Call)

Not too often we get a good coastal storm without a notable blocking pattern in the Atlantic, but here we are.

Emphasis on the “coastal” part. Without the blocking pattern in the Atlantic, there isn’t much to shove the coastal storm more inland, so what’s left is a mostly I-95-and-east event for the Mid-Atlantic. What’s not shown on the map is the wind, and boy is it going to get windy during the tail end of the storm and beyond. Some power outages are likely in the 4-8″+ zone. As the system departs the Mid-Atlantic, gusts behind it will kick up to the 30-40+ mph range, so look out for blowing snow and drifts across the roads!

There’s definitely going to be some mixing issues in far eastern North Carolina and perhaps briefly around Virginia Beach and the far southeastern Delmarva Peninsula, but other than that, we’re looking at full-on snow.