Good afternoon! Hope everyone is having a tremendous day… Let’s talk about our incoming storm system, high thin clouds are already streaming into the region from SW to NE out ahead of our approaching system, this is our first early indicator of our storm, next and more invisible would be the winds have shifted out of the South and the barometric pressure is slowly beginning to fall. The overall trend in the guidance this morning has been a continuation of what we were starting to see during yesterdays update, the cold front is arriving a bit earlier and its effects are for a slightly colder solution. Let us be clear, this by no means is saying a major snowfall is upon us, but in a winter like this every inch seems significant.
Precipitation WILL still change over to plain rain across MOST of the region before morning light, the exception to this rule is the higher elevations of the Catskills where freezing rain is likely especially above 1500′ and rising through the morning. Travel conditions will vary widely by most of the regions morning commutes, there is a lot of variability in this part of the forecast. Things to consider.. surfaces are not all that cold after two days of highs around 40 degrees, that combined with a change over to moderate to heavy rainfall would lead to rapidly improving conditions. The all clear can’t be given due to the fact that colder air will linger across the northern zones and the change over in these areas may be later and closer to daybreak, some sheltered locations may see a brief period of freezing rain before change over. In short, don’t expect along your journey what you found in your driveway.
So lets get some graphics up, they tend to always help with tying together all the nerdy talk above to what’s gonna actually happen…
Above is the HRRR Model Radar Simulation for the entire event, it shows precipitation encountering the colder air and producing and onset thump of moderate to heavy snow, its duration is limited by your location, if your across southern parts of the region its a very brief period of snow. The duration goes from zero to several hours depending what exit you get off of while heading North on I87.
Above is the NAM and HRRR model projection for snowfall across the region, remember the models do not calculate for snow melt that occurs on contact with warmer surfaces, only how much would be on the ground if 100% of the QPF was to accumulate efficiently, in laymen’s terms don’t ever take a snowfall model projection verbatim, for a multitude of reasons. Only interesting differences between the NAM and the HRRR as of this afternoon is the temps at 5000′, the NAM is colder for longer and also doesn’t retreat the freezing air as far north. OK Alex, why does that matter? Well… The intensity of the precipitation will be quite heavy, this is due to impressive lift over the region, when temps at 5000′ are sub-freezing the intensity of falling snow can help cool that column of air down to the surface, this is called “Dynamic Cooling”, when this occurs you can get prolonged snowfall, notoriously missed on model guidance. This can lead to some overachieving on snowfall amounts, AGAIN nothing will make this a MAJOR storm, but an extra inch or two? Maybe..
Now let’s talk details, minus out the nerd talk, especially considering a bunch of you don’t read it and then yell that you were surprised about something…. sigh….
Starts- SW TO NE Between 9:37:30 PM and 12:28:55 AM
Ends- W to E Between 10:21:44 AM and 1:12:21 PM
Green Circle- Trace amounts of snow, maybe a coating on the NW fringes, quick onset to rain with some locations seeing all rain.
North and NorthWest of Line- Coating to 3″ snowfall amounts and duration of snowfall from hour or less to four or five hours in northern most locations. Snowfall amounts will of course be the heaviest in areas that stay snow the longest.
Pink Circle- 1″-5″ of snow and a 1/4″ or more of freezing rain short duration of rainfall across terrain above 2000′.
Thats about summarizes the situation, you can tell we’re board when your getting such in-depth analysis of a coating to three inch storm…………………………….kicks a rock while staring at the ground……. alright folks, I’m out! Stay Tuned.