As this storm across the area continues to develop, we are watching closely the potential for a flash freeze tonight as temperatures look to drop up to as much as 20 degrees in 3 hours, or 6-7 degrees per hour. Around 10 or 11 PM tonight we see temperatures begin to plummet, and they will bottom out in the upper teens or low 20s by 4 AM or so after starting in the mid 40s. The power of cold air advection will be seen as the low pressure center moves to our east and pulls in a lot of cold air.
So here’s what we are looking at for real conditions this afternoon and evening into the overnight hours: rain showers are beginning to break out now, with the steadier rain beginning around 5 or 5:30 PM across the region. There’s a pretty steady wall of moderate to locally heavy rain that will continue until somewhere in the 9-11 PM period. There may be a break for an hour or two somewhere in there, but I expect another line of moisture to move through between 8 and 10 PM. After that line moves through, we see winds turn to the northwest and temperatures rapidly plummet with temperatures dropping below freezing by 11 PM or midnight across the area. All standing water from any rain today will freeze, and wet roadways will become very icy unless treated. Luckily, as temperatures drop the air will rapidly dry out as well, so I don’t expect ice to be widespread which is why I am not yet forecasting widespread school delays tomorrow.
After midnight or 1 AM, with temperatures at the surface below freezing, freezing drizzle will likely be an issue until 2 or 3 AM. Then we will have light snow/flurries possible until 7 AM or so when the chance goes away. The latest short-range models indicate precipitation is slightly more likely inland that at the coast, but no more than a light glaze of ice and maybe a half inch of snow are possible overnight. It will be enough to coat roads, and that, combined with the flash freeze, is where there is a chance of school delays. The sun will be out by 9 or 10 AM at the latest tomorrow and conditions improve, but winds will be gusty even throughout the day tomorrow. They peak in the early morning between 4 and 8 AM, but only slowly taper off, so expect very low wind chills throughout the day tomorrow.
So, overall, we see rain through the afternoon/evening, with a flash freeze overnight and some light snow into the early morning, accompanied by gusty winds up to 40 mph overnight tonight into the day tomorrow. Temperatures then begin to rise Friday and Saturday as more seasonable weather returns, but we are tracking another potential winter storm Sunday night into Monday, so stay tuned for that as well. Ironically, I have a meteorology midterm tomorrow that is taking up a lot of time, but I will continue and try and get all the updates out that I can today and will have multiple more delay updates throughout the evening. I’ll be back at 5 AM to report on delays tomorrow morning as well, so make sure to stay tuned for the latest updates on the storm across Southwestern Connecticut.