Schools are closing, and if they are doing it this early in the evening then that means they have very high confidence that the storm will disrupt Southwestern Connecticut enough for it to be absolutely necessary. I am in complete agreement. The timing of the snow looks the same here, with snow breaking out generally between 3 AM and 4 AM, but flurries/snow showers on the front end could start as soon as 2 AM. HRRR and RAP short range HD weather models are finally coming into range and they show that the snow is tracking on time for the region. The only way schools could open is if the heavier snow waited until 8 or 9 AM and then schools could maybe wait and hope that precipitation turned to rain by 2 or 3 PM, but with 6-10 inches of snow falling during the day tomorrow even then I don’t believe roads will be safe for travel. I understand there have been many snow days, but this is a very serious storm and I expect every district to close, hopefully most tonight to make it easier for everyone else.
So snow starts between 2 and 4 AM, and I think by 6 AM there will already be an inch on the ground. By 8 AM there will likely be 2 inches, and by that point we are looking at very heavy snow. Between 8 AM and 1 PM there could be periods where snowfall rates reach 1-2+ inches per hour, especially around the 10 or 11 AM hours. This means I expect the most dangerous travel to be late tomorrow morning, though of course it will be dangerous enough by 6 AM to warrant schools closing across the entire region. There is a 5% chance that the storm radically changes and schools can open, and I will continue watching that, so it isn’t a “guarantee” in that it is not a 100% chance but I honestly see no way a school can open on good faith tomorrow. This forecast overall results in 5-9 inches of snow by 12 or 1 PM, and that is when mixing could come into play. Another inch or so is possible over the next hour or two as snow mixes with rain, especially at the coast. The extent of mixing is still being debated, and a lot of that depends on observations over the next few hours. I will focus on that much more in an update to come at 7 PM. This one I wanted to focus mainly on school impacts.
So with 6-10 inches of snow on the ground by 2 or 3 PM and heavy snow for the morning commute, all Southwestern Connecticut schools should close. Any change to rain will then gradually move back towards snow between 9 and 11 PM tomorrow night as a deformation band of heavy snow swings through. Anywhere from 1 to 4 additional inches of snow will be possible through 3 or 4 AM, and this has the potential to delay school districts on Friday and maybe cancel school for those that have half days. This forecast depends on what happens with the back end of the storm, so that will be followed closely tomorrow and I will not release delay/snow day percentages for Friday in Southwestern Connecticut until late tomorrow morning or early tomorrow morning. Of course be sure to stay tuned for that.
Other than that, no major forecast changes at this time. All accumulation forecasts seem on track, and the limited observations I have had time to look at continue to support the going forecast. I wanted to get this update out ASAP as I have not had one in awhile, and the next one will look more at the meteorology behind the storm, why I am forecasting what I am, and where I have higher confidence vs. lower confidence. Also, looks like winds could be a bit stronger than I expected, though I am expected no more than isolated power outages at best. Make sure to check back in for the 7 PM update for more on that, and keep it here throughout the storm with the most local Southwestern Connecticut storm coverage.