The biggest threat of the season is almost here and already virtually all of the weather outlets have downsized their predictions pointing to a bust scenario being more likely. Currently the National Weather Service believes 5-7 inches will fall in Baltimore and 4-6 inches in DC:
This is because significant mixing with sleet is being portrayed by the models due to their belief the storm is going to directly hug the coast now as it passes by us. Here’s a loop from the High Resolution Rapid Refresh (HRRR) model showing an extended period of sleet for I95 in the Mid-Atlantic. This is one such possibility, but usually the sleet band is slightly thinner than what is being portrayed:
But there’s still room for both boom and bust – the first flurries started flying around 6pm in the Baltimore area, a solid three hours ahead of model forecasts, so already the storm is behaving a little different than expected. It may mean nothing, but no storm has ever gone exactly as a model predicted even at event time. And interestingly, the “expect at least this much” (10 percentile) and “potential for this much” (90 percentile) graphics have changed to both lower and raise totals across the area.
The 10 percentile graphic shows nothing for the I95 corridor now:
But the 90 percentile graphic shows an even larger area of 18+ inches intersecting with the Baltimore City line:
So while the National Weather Service has lowered expectations overall, there’s actually more uncertainty in their forecast than there was yesterday.
As for the models, the 12z euro gave 7 inches down the I95 line:
The 18z GFS gives 4-6 inches:
The 12z Canadian gives big amounts, but much of this is sleet being translated as snow on the map:
As for my forecast if I could change it, I would downsize too with a few inches of snow followed by significant sleet. Wednesday is going to be very cold behind this system with temperatures not getting above freezing, a rarity for mid-March. That’s all I’ve got.