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.

The mid-day model runs diverged fairly significantly with the snow possibility for Monday night into Tuesday. First up was the GFS, which had a coastal hugger and inland track once it got up to northern New England. The hugging of the coast resulted in the rain/mix line going over top of the I95 corridor for the Mid-Atlantic in the middle/end of the storm resulting in what would likely be a 6 or 8 inch slop when it was all said and done. The Canadian came in next and its 12z run took the storm east with virtually no snow for the I95 corridor in the Mid-Atlantic. The euro then came in splitting the difference and giving all snow to the I95 corridor and southern MD with accumulations likely over a foot.

Out of the three, I find the GFS and euro scenarios to be the most likely with the Canadian being the more unlikely of the three. In fact, the Canadian’s upper level energy was weaker than the other two and its model run formed a rather odd looking double barrel of low pressure oriented north-south out over the Atlantic. It was odd given the scenario and the surface low pressures splitting like this and weaker upper level energy may have been a result of the model initializing poorly. The 18z GFS was nearly identical to the 12z run, but it made a small step towards the euro’s solution in the upper levels of its model run.

Perhaps the best sign for snow lovers is the euro ensembles that came in the middle of the afternoon. The ensembles gave Baltimore a 50% chance of a foot of snow or more. This is a quite high probability this far out and would be a huge fail for the euro model suite if no snow were to fall for Baltimore.

My decision on whether I think snow is a probability or not will come Saturday afternoon.