Good evening to you from Southern Connecticut Weather!
We're currently dealing with a real mess of a system - freezing rain and drizzle is falling across most of the state and it's leading to some slick spots on the roads. If you have to head out tonight or tomorrow morning, please take it very slow on the roads and use caution when walking around on untreated surfaces as they could be very slippery!
Tonight-Tomorrow
For the rest of tonight, we'll see rain and freezing rain showers across the state, becoming more widespread in coverage as we approach tomorrow morning. As the morning goes on tomorrow we will see warmer air attempt to work into the boundary layer and turn any freezing rain over to plain rain, but with a drain of low level cold to the north this is a situation where it will be difficult to warm the surface enough to get temps over the freezing mark, especially in the valleys. This is shown well on the hourly HRRR below - note the areas of freezing rain remaining into mid-day in the Connecticut River valley and up in the quiet corner of Windham County.
We're currently dealing with a real mess of a system - freezing rain and drizzle is falling across most of the state and it's leading to some slick spots on the roads. If you have to head out tonight or tomorrow morning, please take it very slow on the roads and use caution when walking around on untreated surfaces as they could be very slippery!
Tonight-Tomorrow
For the rest of tonight, we'll see rain and freezing rain showers across the state, becoming more widespread in coverage as we approach tomorrow morning. As the morning goes on tomorrow we will see warmer air attempt to work into the boundary layer and turn any freezing rain over to plain rain, but with a drain of low level cold to the north this is a situation where it will be difficult to warm the surface enough to get temps over the freezing mark, especially in the valleys. This is shown well on the hourly HRRR below - note the areas of freezing rain remaining into mid-day in the Connecticut River valley and up in the quiet corner of Windham County.
Given the rain of both the liquid and freezing types that we're expecting tomorrow, it won't be a great travel day across the state, but given that it's one of the last shopping days of the season I'm sure many of you will need to be out tomorrow. If you can hold off on your travel until later in the day, you'll have a better chance of avoiding any freezing rain, but if you do need to go out in the morning keep a close eye on the car thermometer and leave plenty of space around you in the event that you lose traction.
Sunday
Clear and cold for Sunday as high pressure briefly crosses the area before our next system. Should see highs in the mid to upper 30s and sunny skies - a great day for your last minute Christmas shopping or holiday travel!
Monday
As the title of this discussion suggests, I'm certainly dreaming of a White Christmas, and if you believe the guidance it looks like we could see one across at least part of the state for the first time since 2009. A shortwave enters the area from the west Sunday evening and interacts with low pressure off the coastline, strengthening the coastal system and eventually causing it to become the primary. While this won't be a major event, it looks like we'll see somewhere between a quarter and a half of an inch of liquid across most of the state, enough for a few inches of snow in places where it remains all snow, which will likely not be everywhere due to warm boundary layer temps.
The challenge of this forecast then is predicting where the rain/snow line will develop and how quickly it will move south and east. A couple of things influence the ultimate placement. First off, the guidance has been varying a bit on the position of the low pressure system. The Euro amplifies the system more than the GFS and so correspondingly the system is a bit further northwest; that results in warmer air being drawn into the boundary layer and so temps are a hair warmer as a result. Here's a look at surface temperature on the Euro and GFS for 4 AM Christmas morning.
Sunday
Clear and cold for Sunday as high pressure briefly crosses the area before our next system. Should see highs in the mid to upper 30s and sunny skies - a great day for your last minute Christmas shopping or holiday travel!
Monday
As the title of this discussion suggests, I'm certainly dreaming of a White Christmas, and if you believe the guidance it looks like we could see one across at least part of the state for the first time since 2009. A shortwave enters the area from the west Sunday evening and interacts with low pressure off the coastline, strengthening the coastal system and eventually causing it to become the primary. While this won't be a major event, it looks like we'll see somewhere between a quarter and a half of an inch of liquid across most of the state, enough for a few inches of snow in places where it remains all snow, which will likely not be everywhere due to warm boundary layer temps.
The challenge of this forecast then is predicting where the rain/snow line will develop and how quickly it will move south and east. A couple of things influence the ultimate placement. First off, the guidance has been varying a bit on the position of the low pressure system. The Euro amplifies the system more than the GFS and so correspondingly the system is a bit further northwest; that results in warmer air being drawn into the boundary layer and so temps are a hair warmer as a result. Here's a look at surface temperature on the Euro and GFS for 4 AM Christmas morning.
The other thing we need to consider is the strength of the cold air source to our north. We have a strong high to our north that will allow us to advect cold air in at the lower levels as the storm strengthens and therefore see a "flash" from rain to snow as the rain/snow line moves southeast. We'll need to keep an eye on that high in future model runs, as if it continues to trend stronger we could see a colder solution prevail(and of course the inverse is true as well). Finally, the timing of the system is important. If we see a trend towards earlier development, that will allow for stronger cyclogenesis before it reaches our area and therefore a colder airmass - a side effect of that solution would also be higher snow totals due to a strong storm. So far, we haven't seen a defined trend in that direction, but still something to keep an eye on.
So you're probably thinking "SA, that's cool, but is it going to snow in my backyard for Christmas?" The answer depends on where in the state you are. While I do think that everyone will at least see some flakes on the back end of the system as it pulls out, accumulations will likely vary on a NW/SE gradient. If you're north and west of I84, you should be in good shape for a mostly if not all snow event, and are probably looking at an advisory level snowfall. In the area between I84 and the immediate shoreline as well as the western shoreline, you're probably looking at some rain to start, but things should flash over to snow as the storm strengthens and colder air comes in and that should be in time for at least an inch or two of snow to accumulate - a small shift colder in the guidance and you're looking at an advisory level snow as well. For the eastern shoreline and southern New London county, there will definitely be a period of rain that could use up a good portion of the QPF, but the good news is that you are going to be the last ones to have precipitation exit and thus have the longest time to take advantage of colder air moving in. As such, I think you'll at least see some flakes on your Christmas morning and if we get a good band on the backside of the system(which the models have been hinting at) it shouldn't be too hard to pick up a light accumulation. Assuming no drastic changes overnight, we'll have an official snow map out tomorrow morning.
Snow should be out of the state by 10 AM or so, leading to a mostly cloudy afternoon with seasonably cool temps in the low to mid 30s - great weather for snowball fights, igloo building, sledding, or Christmas feasting!
Tuesday-Thursday
Quiet and COLD weather for the middle of the week as arctic air advects into the state. Per the GFS and Euro, we'll see highs ~10 degrees below normal on Tuesday and Wednesday and 15 degrees below normal on Thursday, and the lows are even further below average! Here's a look at low temperature anomalies and actual readings for early Friday morning from the Euro.
So you're probably thinking "SA, that's cool, but is it going to snow in my backyard for Christmas?" The answer depends on where in the state you are. While I do think that everyone will at least see some flakes on the back end of the system as it pulls out, accumulations will likely vary on a NW/SE gradient. If you're north and west of I84, you should be in good shape for a mostly if not all snow event, and are probably looking at an advisory level snowfall. In the area between I84 and the immediate shoreline as well as the western shoreline, you're probably looking at some rain to start, but things should flash over to snow as the storm strengthens and colder air comes in and that should be in time for at least an inch or two of snow to accumulate - a small shift colder in the guidance and you're looking at an advisory level snow as well. For the eastern shoreline and southern New London county, there will definitely be a period of rain that could use up a good portion of the QPF, but the good news is that you are going to be the last ones to have precipitation exit and thus have the longest time to take advantage of colder air moving in. As such, I think you'll at least see some flakes on your Christmas morning and if we get a good band on the backside of the system(which the models have been hinting at) it shouldn't be too hard to pick up a light accumulation. Assuming no drastic changes overnight, we'll have an official snow map out tomorrow morning.
Snow should be out of the state by 10 AM or so, leading to a mostly cloudy afternoon with seasonably cool temps in the low to mid 30s - great weather for snowball fights, igloo building, sledding, or Christmas feasting!
Tuesday-Thursday
Quiet and COLD weather for the middle of the week as arctic air advects into the state. Per the GFS and Euro, we'll see highs ~10 degrees below normal on Tuesday and Wednesday and 15 degrees below normal on Thursday, and the lows are even further below average! Here's a look at low temperature anomalies and actual readings for early Friday morning from the Euro.
We'll see if these numbers moderate somewhat as we get closer in time, but for right now it certainly looks possible that we could see our first below zero readings of the season next week. Bundle up!
Friday-Saturday
Our next system of interest is way out at the end of the forecast period. Both the Euro and GFS along with their ensembles have been steadfast in phasing the northern and southern streams in this period and creating a classic Miller A coastal storm, which are known to be some of our most prolific snowmakers. While it's far too early to talk details and specifics on dates/timing/amounts/etc because the guidance is all over the map, the possibility certainly exists for a significant system to close out next week. We will continue to keep an eye on the models and keep you informed as things start to come together with some degree of confidence. Until then, here's a peek at the GFS for this system - if you don't like what it shows, don't worry, it'll probably change in a few minutes when the 0z run comes out :)
Friday-Saturday
Our next system of interest is way out at the end of the forecast period. Both the Euro and GFS along with their ensembles have been steadfast in phasing the northern and southern streams in this period and creating a classic Miller A coastal storm, which are known to be some of our most prolific snowmakers. While it's far too early to talk details and specifics on dates/timing/amounts/etc because the guidance is all over the map, the possibility certainly exists for a significant system to close out next week. We will continue to keep an eye on the models and keep you informed as things start to come together with some degree of confidence. Until then, here's a peek at the GFS for this system - if you don't like what it shows, don't worry, it'll probably change in a few minutes when the 0z run comes out :)
The Dailies
Here are the dailies:
Saturday: Rain and freezing rain likely. Highs in the mid 30s(sheltered valleys) to mid 40s. Chance of precipitation is 90%. Light ice accretion possible.
Sunday: Partly sunny, with highs in the mid to upper 30s.
Christmas Day: Rain and snow likely in the morning, then mostly cloudy. Highs in the low to mid 30s. Chance of precipitation is 80%. Moderate snow accumulation possible.
Tuesday: Partly sunny, with highs in the low to mid 20s.
Wednesday: Partly sunny, with highs in the low to mid 20s.
Thursday: Partly sunny, with highs in the mid to upper 10s.
Friday: A chance of snow, otherwise, mostly cloudy, with highs in the low to mid 20s. Chance of precipitation is 50%.
Saturday: A chance of snow, otherwise, mostly cloudy, with highs in the low to mid 20s. Chance of precipitation is 50%.
More to come tomorrow morning on our Christmas snow event, until then, stay safe out on the roads tomorrow and thank you for reading SCW!
-SA
