As Greg discussed last night, we’ve got dangerously cold temperatures on the way for tomorrow and Friday, followed by accumulating snow on Saturday for the entire state. This discussion will take a first look at that storm system and give you some early thoughts on accumulations. We’ll also take a look at the cold and wind expected for tomorrow into Friday and see just how cold it’s going to get!
Part 1: The Arctic Blast
A strong arctic shot is currently tracking eastward towards us. You can see on the current temperatures map that the core of the cold is currently located over the upper Midwest and Plains, where daytime highs are below zero today! That cold will translate east into our area over the next ~24 hours, leading to a frontal passage tomorrow morning and much colder temperatures in our area by tomorrow afternoon. Here’s a look at the progression of temps throughout the day tomorrow on the hires NAM.
We could also see some snow squalls tomorrow and Friday off the great lakes – best chance for those will be in the northern and western portions of the state. Any snow that falls will be very high ratio due to the cold temps, and so a quick light accumulation is possible wherever any squalls develop. Overall, a bitterly cold taste of the arctic is on tap to close out the week. We’ll warm up as we move into the weekend, but before we do, we’ll get to experience another part of winter as a snowstorm approaches for Saturday morning, bringing us to:
Part 2: Saturday Snow
Models and Trends
If you followed our discussions for Monday’s event, this may read like a broken record, as we’re looking at a similar sort of system. A weak area of low pressure will bring overrunning precipitation over our area early Saturday morning (formed when warm air overruns a colder airmass closer to the ground), and will bring accumulating snow to the entire state from early Saturday morning through midday. Models are in excellent agreement on the overall track and timing, and the only differences that remain are relatively minor ones regarding the onset of the precipitation and the arrival of the warmer air. To illustrate, here’s a look at the GFS, GGEM and NAM for 7 AM Saturday and 1 PM Saturday.
Over the past couple of model cycles, we’ve seen a trend towards bringing in the initial precipitation faster and disconnecting it from the main storm out to our west somewhat. This serves two purposes. First, it flattens out the trough behind it and means the followup portion of the system on Sunday is not as amplified, and secondly, it brings the precipitation in ahead of the warming midlevels, giving us longer period of time in a snow column before temps rise. If this trend continues, we may have to increase snow amounts somewhat tomorrow or Friday, but I’m not ready to do that just yet. Similarly, if we see a reversal of that trend, we will have to lower amounts, especially along the shoreline.
Behind the system, we will see a quick break in the rain as the first round of precipitation moves out, then temps will spike into the 50s for most on Sunday as the primary low passes to our west. This will bring some more rain, possibly changing to snow on the back end Sunday evening as temps crash back into the 20s and eventually teens by Monday morning, causing a flash freeze of whatever has melted. We’ll take a closer look at that part of the storm tomorrow.
Forecast and Timing
Normally, we would wait until 48 hours before first flakes to issue a snowmap, but considering the model consensus, relatively low bust potential, and the fact that Saturday is the biggest shopping day of the year and there will be a lot of people out and travelling, we decided to issue a preliminary forecast this evening. Here’s a first look at our expected snow totals.
As far as timing goes, expect snow to break out in the wee hours of Saturday morning, with the whole state seeing snow by daybreak. Snow will change to rain over the course of the morning from south to north, and the whole state save the hills should be raining by the early afternoon. Rain will move out Saturday evening and we’ll see a break overnight before the rain from the primary system comes in for Sunday.
- A plowable snowfall for most of the state, with a low chance of warning criteria accumulations in the NW hills.
- Difficult travel conditions Saturday morning.
- Moderate risk of power outages due to a combination of snow and the stress from Thursday-Friday’s wind.
- Flash freeze potential Sunday evening due to melting snow and additional rain.
Overall, it looks like a moderate snow event for the state that comes on the back end of a bitterly cold arctic airmass. Please ask us any and all questions you have here, on our Facebook, or on Twitter @SouthernCTWX. Also, please consider sharing this discussion with your friends and family to spread awareness about this system. We’ll be back with an update tomorrow evening and a final call will be issued tomorrow evening or during the day on Friday – until then, thank you as always for trusting SCW!