Good evening from Southern Connecticut Weather. 

Can you do, what you do, when you absolutely have to do it.

There are no higher stakes than when the hype is high, a big storm is coming, and all eyes are on you to get the forecast right. There is a lot to consider. If you come in too high with snow totals, the public may consider the storm (or forecast) a bust. If you come in too low, people may be caught unprepared for the severity of a winter storm. Big storms are when you have to be at your best. 

With confidence in a big storm higher than normal, we issued our first call forecast for a "blockbuster" storm on 1/22--earlier than normal. There were a number of ways we could have gone, especially considering the risk of mixing that was showing up on models. With even more uncertainty by the time we issued our final call forecast, we stuck to the first forecast. 

​Did that work out? Let's take a look. 

Above: the final verification map, using NWS reports and approximate locations. Unfortunately, the New York NWS never issued an update to the Sunday totals, so the numbers in southern CT may be lower than they actually are. Special shoutout to Jacob, a budding meteorologist who wants to follow his passion when he gets to college, for submitting one of the Vernon snowfall totals! 

Timing
Despite uncertainty over onset timing, we did an excellent job. 

There is a chance the onset time slides a little later in the morning, but overall the expectation is that snow begins from SW to NE between 6-10am. It may take a little time for the atmosphere to saturate because temperatures will likely be near zero or in the single digits Sunday morning, but once things get going we will quickly go to moderate and heavy. It is strongly advised to be off the roads once this begins. 

Sure enough, while some areas started a little before 6am, Bridgeport reported its first snowflakes at 6:20am. Indeed, once we started snowing it did not take long for moderate and then heavy snow to start falling across the state. We were a little off with the timing of sleet, but not by much. We were right in timing the heaviest snow. Overall the timing forecast was excellent, though looking back at the forecast I could have been a little clearer in discussing the end time rather than just referencing models. 

Grade: A

Snow Accumulation
This is an aside, but for the first time in 10 years we had a storm bring 6" of snow from DC to Boston. It was a pretty easy call in hindsight, but pattern recognition is important and it was spot on here. This was a big dog, with this being a top ten snowstorm for Hartford (BDL) and top 15 for Bridgeport. 

The soundings that I posted were very helpful, because they helped our forecast that the mixing line would not significantly hurt snowfall totals. That was the biggest unknown in the forecast, and we were on the money in the face of some guidance wanting to punch the sleet line deep into the state. To be sure, there were lower totals right along the coast, but all but a baffling 9" report and 10" report were within an inch of our forecast. Several coastal communities were over a foot, including Bridgeport. 

In addition, we added text calling for isolated amounts over 20" in NW and/or NE CT, and in NW CT we had isolated reports. The forecast was as good as you can get. Going 8-12" in southern CT would've been too low. Excellent, excellent call. 

Grade: A

Wind & Power Outages
We didn't expect significant wind and that was the case. It was breezy but never overwhelmingly so. Power outages were minimal as a result. 

Grade: A

Overall Impact
We were very clear that this was going to be a high impact event. 

This is likely to be a high end event. There will be heavy snow, high end accumulation, and cold temperatures throughout the storm, especially if the mix line remains well to the south. Road conditions will be severely impacted from Sunday possibly through Monday, with residual impacts possible into Tuesday. Everything is likely to be closed on Monday, with a chance of delays and cancellations on Tuesday.

We had very heavy snow for much of Sunday which led to those high end accumulations. It was the coldest storm that we've had in a while as well, with snow starting with many locations in the single digits and wind chills below zero. Roads were a mess as expected and not only did we have issues Monday but residual delays and cancellations on Tuesday. Excellent call. 

Grade: A

Overall Grade
I didn't even need to calculate the numbers! This may be the first time that I can recall that we were solidly in A territory all the way through. Very proud of this forecast. Only downhill from here haha. 

Final Grade: A

A​s always, please like, share, and interact with us on our social media--on Facebook to share our discussions, and follow us on Twitter @southernctwx to retweet our posts. Hit the buttons below to join.
​
Thank you for reading SCW.

​-DB

Good afternoon from Southern Connecticut Weather. 

It's time.

A major winter storm is already delivering snow, ice, and rain to the southern Plains and south. With extreme cold continuing to pour into the country, there are southern locations that are snowing in the teens and single digits! 

This unusually cold and expansive air mass will heavily influence our potential snowfall, with the cold essentially enhancing the potential for a high impact storm with big snow totals across Connecticut. 

So what is this that you're hearing about mixing?

Let's dive in. 

Above: the final call forecast map. There were a lot of competing ideas that could have changed things, like the risk of mixing along the coast or the aggressive nature of some high resolution models. In the end, however, a broad 12-20" works. We did introduce special text for the NW and NE hills, which may have some areas with over 20" due to the long moisture train potentially maximizing accumulation there. 

Overall Setup
Nothing has changed. I'll repeat it once more: extreme temperature regimes can trigger extreme atmospheric responses. Today we see this in action with the winter storm continuing to move through the south. 

Above: national radar image of our winter storm spanning New Mexico to Virginia. The storm will continue to grow in geographic scale. 

We have cold from the north, and we have moisture coming from the Gulf overrunning the Arctic dome. The scale of the cold allows for maximum moisture to be wrung out as the warmer air lifts over the cold, condenses into clouds, and falls as precipitation. 

Above: a visible satellite image of the storm.

Because of the 500mb interaction between northern and southern lobes of energy, this storm will grow, spawn a coastal low, and ride up the coast. While the low overall will present like a nor'easter, the overrunning setup and displaced 850 and 700mb lows will make this more of a supercharged southwest flow event. This is critical to the question of mixing. 

You can see this in the GFS depictions above. In the top image you see what happens at the surface. A low develops, slides off the coast, and stays to our south. However, if you look at the second image, which looks at 700mb, you will see that this section of the storm is a little further west. That looks slight, but it's significant, as it forces warmer air aloft from the southwest. This erodes the cold aloft, but not before an epic battle between warmth and cold which effectively wrings out even more moisture. 

Regardless of whether sleet moves into the coast or not, the overall evolution is the following: 

The storm rolls in as all snow because it is well below freezing below the entire column. The lift over the Arctic dome of cold will produce intense snowfall rates for a significant period of time. As the mix line gets closer to the coast, the more fluffy snow may turn heavier and wetter. Any mixing would be most likely as the intensity of the snow diminishes and the region may enter a pseudo dry slot as the 500mb evolution holds back the storm and likely wrings out more snow on Monday that is higher ratio before departing. 

The Forecast
If you are a new follower, we grade our big forecasts for accountability and accuracy. We are graded on what the final forecast is, with snow accumulated weighted 2x to account for its importance. 

Timing
There's still a little uncertainty over end time, but overall there is a much better handle on things now for a moderate confidence forecast.

Snow should begin from SW to NE between 7-11am. That means if you are in SW CT expect snow on the earlier side of this range and if you are in NE CT expect it during the latter side of this range. If you're in the middle of the state, be prepared for the middle of the range. While you may be able to get around for a short period after it begins snowing, you probably want to be at your location no more than an hour after the snow starts where you are. The combination of deep cold and fast onset of moderate to heavy snow means that road and visibility conditions will quickly deteriorate. Don't go driving unless you need to. 

The afternoon is really where things start to get intense. There is high confidence in high snowfall rates. This system will be able to effectively produce snow due to an unusually large dendritic growth zone--basically the place where the atmosphere produces its snowflakes most efficiently. Sometimes you need to be on the razor's edge to get the best banding, and that is what may happen here as the mix line tries to move into coastal CT. High resolution models show an extended period of snowfall rates above an inch of snow per hour.  

Above 12z HREF probabilities of 1" per hour rates tomorrow afternoon. That's as close to high confidence as you can get. 

One of the big questions is whether or not we mix.

Yes. There is likely going to be some sleet.

Now lets put that into context. It's not a guarantee. Global models like the GFS and Euro have generally kept the mix line either offshore or just onshore. The NAM however, which is very good at identifying warm noses (warm air aloft) historically, tries to punch the mix line into CT. We give it some respect here.

We're not as concerned that this will significantly cut back on snow totals. Why? Because the initial burst of snow is extremely potent, even bringing a chance of thundersnow. 

Here's the 12z high resolution NAM. 

If you want all snow, that's the worst case scenario, as the warmth aloft punches the mix line all the way into northern CT.

Now look at the same model, six hours later. 

The mix line still reaches CT, but it's more suppressed. That tells me that the model is having trouble resolving the extent of the warm nose.

In addition, look at the frames before mixing. That is a hellacious thump of snow that falls. While other models bring the mix line close to the state, none are as aggressive as that one run. As a result, we think that while sleet does occur late on Sunday, it happens in coastal CT, and maybe gets a little further north after the main batch of precipitation is done. This is critical, because it means that it would not significantly impact snowfall amounts. Southern CT is still likely to see a high end, double digit snowfall. 

After the main batch pulls away around midnight Monday, we will watch for regeneration on Monday as the storm tries to pull away. That means that Monday is likely to be snowy with lighter, but higher ratio snow. Don't think the storm is over because things get light or stop late Sunday night and early Monday morning. Accumulating snow should be done by 5pm Monday. 

Snow Accumulation
I've already talked about the depth of the cold, but just to visualize it one more time, here are soundings for Hartford (city) and Bridgeport during the peak of the system tomorrow afternoon. This strongly suggests very heavy snow. Note the sounding for Bridgeport with an ever so slight warm nose. Sometimes you have to get close to the mix line to get the best rates. These soundings could produce upwards of 2" per hour. 

That is a cold powder look right there. 

With this in mind, we kept the 12-20" zone for the state. Some may wonder why the zone is so large, but this is really to account for the variation in banding that we can see in high end storms. The likelihood that this is a general southwest flow event reduces the chances that we see extreme variation like we do in pure nor'easters but there will be some that get 12" and there will be someone a town or two over that gets 16". That's just how it goes. 

Now, just because it says 20", that doesn't mean that everyone should be thinking 20" in their backyard. If you get 12" that's not a bust. I'd consider anything under 10" a bust in a location, and anything over 24" a "positive bust". Someone in the NW and NE hills may get close to 24" as the persistent easterly moisture train piles up against the hills, hence the wording, but everything in the world would need to break favorably for long duration snow for that to be widespread around CT.

For lower totals, which are most likely in coastal CT and especially SE CT, sleet and or dry slotting would need to arrive earlier than expected or last longer than expected. Again, not expecting that to happen here, but coastal areas know the deal--you're usually the "low" spot. The forecast is lower confidence here. 

Wind & Power Outages
We still do not expect significant wind, though some guidance has turned a little more breezy. We probably don't see wind gusts higher than 20-35mph, which is no big deal with regard to power outages, but would impact visibility and the wind chill during this event. 

What we will be watching for however is the potential for heavier wet snow along the coast should that mix line get closer to us late Sunday. Without strong wind heavy wet snow probably isn't too big a deal for power outages, but out of an abundance of caution, we will forecast a low chance of outages in that region. Nothing to be too concerned about, but just as folks should be during every big storm, be prepared, especially if you are in a place that loses power easily. There will be long duration cold after this storm.

Overall, power outages should be isolated. 

Overall Impact
This is likely to be a high end event statewide. Nothing significant has changed from where our thoughts were during the first call. There will be heavy snow, high end accumulation, and cold temperatures and wind chills throughout the storm. The mix line getting close or into CT doesn't substantively change snow totals as we forecast at this time, but it would make shoveling a lot harder. Road conditions will be severely impacted from Sunday through Monday, with residual impacts possible into Tuesday. Everything is likely to be closed on Monday, with a chance of delays and cancellations on Tuesday.

It's not the biggest storm we've ever had but it's legitimately high end. Take it seriously and prepare yourself for the cold that is reinforced in its wake. 

​A​s always, please like, share, and interact with us on our social media--on Facebook to share our discussions, and follow us on Twitter @southernctwx to retweet our posts. Hit the buttons below to join.
​
Thank you for reading SCW.

​-DB

Good evening from Southern Connecticut Weather. 

Last night we talked about an exceptionally potent setup that would trigger a major storm, and now we have high enough confidence in a major hit to issue this first call. Longtime followers know that at SCW we tend to lean conservative--we do not believe in hype, and when we speak, we want to speak from a place of thoughtfulness and no-nonsense analysis. 

So let's set the record straight in case there's any confusion: this will be a blockbuster storm, but we are not expecting a historical impact type of storm. This storm is unlikely to be a Mount Rushmore storm (I believe our top four storms in CT history are the Blizzard of 1888, Blizzard of 2013, Blizzard of 1978, and October 2011 Snowstorm). This is a high end storm, but not on that level.

However, between the snow and the Arctic cold that both precedes and lingers after this storm, we could very well be looking at the most impactful week of winter weather in decades. 

That's a big statement, so allow us the time to back it up with the data. This forecast will look at both the storm itself and the cold, because they heavily impact one another. 

​Let's dive in. 

Above: the first call snowfall map. It speaks for itself. This is a broad brush for now, and as we get closer and get a sense of whether there's a real chance of mixing, and where banding may set itself up, we will likely drill down some more. The "error tail" here would favor us taking the numbers up to an extent, rather than taking them down, but we'll see by the time we issue the final. 

The last time we had a widespread 12" snowfall was 2021. The high end snow totals in the central CT event in 2024 was fairly localized. The last time BDL recorded 18" of snow in a 48 hour period was the Great Blizzard of 2013, where it recorded 22.3" of snow. The last time BDR recorded 18" was also the Great Blizzard of 2013, where it recorded its all time two day record of 30.0".

Overall Setup
The overall setup hasn't changed since last night, except with one crucial change that brings heightened potential...and uncertainty. 

As we said last night, extreme temperature regimes can trigger extreme atmospheric responses. You can see that something extreme is on the way by looking at the national hazard map.

As you can see above, the extreme cold is definitely on the way. We see extreme cold warnings, which replace wind chill warnings, all across the upper Midwest and into New England. You also see cold weather advisories across the Midwest, our region, and all the way into the south.

This is a high end blast of cold in both geographic scope and intensity. It will be the key ingredient in triggering development of our storm as it creates an intense baroclinic zone, that is the boundary between the warmth from the Gulf and cold in the north. As the moisture rises over the cold dome, boom, blockbuster. 

We shared it last night and we're sharing it again, above is what an overrunning setup looks like. The depth of the cold over us will in effect supercharge our storm, as it will help create an environment incredibly efficient at wringing out as much moisture as possible from the atmosphere. 

Last night we mentioned that a more efficient phasing of the northern and souther lobes of energy would trigger a more potent coastal storm, and the trend today has been toward that. Critically, that would extend the duration of the storm, with moisture still getting thrown back into New England well into Monday. 

The GFS, which has been the least bullish to an extent, shows this too today. Note the darker shades of blue on the surface depiction below. That means heavier precipitation. Note also how the snow lasts through most of Monday. If that were to be the case, it would increase the chances of more snowfall. 

Now, with a bigger push of warmth hitting the wall of cold, and the lows above the surface likely cutting to our west, it increases the chance of mixing in coastal areas--after the bulk of the snow has fallen. No one should be reading this and believing that all of a sudden it will be raining in Norwalk at any point during this storm. It will be a frigid storm, and much colder than normal when we're snowing. This is just highlighting that if we have dry slotting (which happens in high end storms) or things tick north it may lead to periods of sleet. That's something we'll be watching. In this instance, being close to the sleet line may mean some high end snowfall rates. 

The Forecast
Ok, so what does this mean for your backyard?

​Big snow. 

Timing
It looks like we're getting into better agreement for timing for onset, but keep in mind that there's still uncertainty over the end time. 

There is a chance the onset time slides a little later in the morning, but overall the expectation is that snow begins from SW to NE between 6-10am. It may take a little time for the atmosphere to saturate because temperatures will likely be near zero or in the single digits Sunday morning, but once things get going we will quickly go to moderate and heavy. It is strongly advised to be off the roads once this begins. 

Above is the 12z Euro, which has led the way and been one of the most aggressive models. Snow begins Sunday morning and quickly goes moderate to heavy. The heaviest happens Sunday afternoon through the the evening. By early Monday morning we likely start seeing the precipitation intensity slacken, and this is one of the periods we think the sleet risk may be at its highest. Note how close the mix line is by about 1am Monday morning. 

This the the higher confidence portion of the forecast, but this is where it gets tricky. 

​Do we get that coastal enhancement to extend snow?

Here's what the Euro depicts, and right now the idea is gaining steam. If the cleaner phase were to happen, it would kind of prolong the coastal low from moving away so fast and enhance snow across much of the region. This is lower confidence, but if this feature were to happen it would enhance the chance of higher snow totals. It'd also mean that Tuesday would also be a day full of cancellations statewide as we clean up. 

Snow Accumulation
This is a big dog. There will be big accumulations from Virginia all the way to Maine. There are a few reasons for this, and they have to do with the depth of our cold. To do this, we need to look at the vertical profile of the atmosphere, a sounding. Below are Hartford (top) and Bridgeport (bottom). 

In both images, a lot stands out. First, there is plenty of cold throughout the column. Even though there's a risk of mixing along the coast, the surface is plenty cold as it stands. 

Second, look to the left. There is excellent lift throughout the column. In this case, the dendritic growth zone is right where we want it, and the lift takes advantage of it for hours. That means we likely get consistent moderate to heavy snow with excellent snow growth. 

Then we have the coastal low. This is where the cold aloft is major. As easterly-ENE flow pulls moisture from the ocean over the region, that moisture just piles up and gets wrung out over the region. We're looking at a high precipitation event, and that, combined with the prospect of high ratios means that we are likely to get big totals. 

If we can get more moisture with the coastal low on Monday to flow over the Arctic air...it just ups the ante. We won't really know if that's probable until Saturday. 

These are ensemble totals for total precipitation for the storm. This combined with higher than 10:1 ratios overall strongly suggest totals in excess of 12". The National Blend of Models (NBM) shows consensus on an inch of liquid at least. 

As a result, we currently have a broad brush of 12-20", with a chance that these numbers are refined some as we get closer and understand where banding (which will promote higher ratios) will land. 

Now, 12-20" is a big zone. That's how it goes in big dog events. Not everybody is going to go that high, but there is enough risk that for now we have that as the ceiling. Hill towns, I'm looking at you. 

Wind & Power Outages
Fortunately, at this time we do not expect significant wind. In fact, that probably helps keep the ratios higher for snowfall, which also meets a fluffy snow. As a result, we think the power outages are minimal.  

Overall Impact
This is likely to be a high end event. There will be heavy snow, high end accumulation, and cold temperatures throughout the storm, especially if the mix line remains well to the south. Road conditions will be severely impacted from Sunday possibly through Monday, with residual impacts possible into Tuesday. Everything is likely to be closed on Monday, with a chance of delays and cancellations on Tuesday.

​We'll get through this, but take it seriously. 

And now, the cold...

High End Arctic Blast

Above: the European model projection for wind chills at approximately 7am on Saturday. A cold weather advisory (replacing the old wind chill advisory) is up for the entire state during this period. 

We have been talking a lot about the winter storm, but we've also been talking about the big Arctic blast. As you know by now, it is responsible for the storm and is coming straight from the Arctic in unusually unmoderated form. 

The big low temperatures that were once projected for the weekend have become more uncertain, as they've moderated some as we pump the heights in front of our Sunday storm. The cold is still legitimate however, and we need to take heed that we're entering what may be a historic stretch of cold weather. We may have gotten a warning shot across the bow earlier this week, when parts of the state went well below zero. 

To be sure, it gets cold in Connecticut. We've had much lower lows and much lower high temperatures than what we're likely to see, but in CT we don't get too hot or too cold, and too hot or too cold for too long because of the moderating influence of the Atlantic. This means that while we may get extreme blasts of warmth and cold, they don't last long. 

That may be different here. 

Digging into the data and comparing it to the ensembles, what I found is that we could be entering a period of consistent cold that we don't see often. Historic doesn't mean coldest ever, but if these numbers get close to verifying we may be in one of our coldest periods in at least the last 25 years if not longer. 

​Let's start with the expected cold. 

Above: the 12z EPS depicting deep and persistent Arctic cold over the eastern U.S. all the way from tomorrow into February. While we may have a "warm" day scattered in there, if not, we may threaten some records for length of cold. 

We can already discern multiple cold blasts. The first happens in advance of our Sunday storm. Saturday and Sunday look frigid. Then we can expect a reinforcing shot of cold as the storm departs Tuesday. From there, we'll see how frequent this overall hemispheric pattern pushes cold into the region. 

Here are predicted numbers by the Euro and GFS ensembles for Hartford and Bridgeport for the foreseeable future. These will change, but I want you to see the trend. 

EPS on the top.

Now for the GFS Ensembles. 

You can take your pick with them, but the length of the cold is extraordinarily impressive. Verbatim, this kind of persistent cold starting Friday would put us in rare territory in terms of length and possible intensity of the cold. 

It was 2018 that we last had a historic long duration outbreak of cold, but once you get past that you need to go to 2015 or 2005, and depending on how cold we get, even further back. 

Days below freezing is easiest to track. The GEFS has 15 days at or below 32 at BDL as a model mean, while the EPS has 14. That would be the longest streak in 21 years, and tied for 4th longest on record. 

​Let's get colder. 

If the ensembles were to verify--keep in mind these are not just operational models we're pulling here, it could mean the longest streak since 2018, and if another day could be tacked on, perhaps the most consistent cold going back much further. 

Let's get even colder.  

This is the coldest, but by far most impressive. Here the Euro and GFS ensembles diverge. If the EPS were right, however, BDL would have a shot at its coldest period using this metric since 2018, or if Monday trends colder--1979. 

For Bridgeport, if that cold snap in the wake of the storm happens, it'd be the coldest stretch using this metric, which is not a cherry picked stat, since 1982. Each blast would possibly come with extreme wind chills as well. 

So while we of course track the storms, we need to be mindful of the cold. What's coming isn't something we see often, and it could be historic. 

A​s always, please like, share, and interact with us on our social media--on Facebook to share our discussions, and follow us on Twitter @southernctwx to retweet our posts. Hit the buttons below to join.
​
Thank you for reading SCW.

​-DB

Good evening from Southern Connecticut Weather. 

Extreme temperature regimes can trigger extreme atmospheric responses as the planet seeks balance. A high end blast of cold in both geographic scope and intensity is poised to trigger the development of a blockbuster storm that may be historic in parts of the south. While the overall pattern has been visible for a while now, we are getting into the range where we can project just how the dominoes will fall. For us, it means big cold and an increasing chance of big snow. 

We're talking over double digits (10"+) statewide.  

While there is still uncertainty over the overall track and evolution of the storm, it's time to take a first look at what we're seeing with more detail. 

If the forecast holds, you can expect a first call forecast Friday and final call forecast Saturday. 

Above: the 12z European model depiction of the weekend storm. The trend has been your friend if you like winter weather, as the entire synoptic (large scale) pattern forces the development of this sprawling storm. 

Overall Setup
​It all starts with the cold. This is not run of the mill cold, as we've been saying for days now. This is extreme cold directly from the Arctic, and is barely modified as it gets displaced into the central United States. 

Above: the 12z European model depiction of 850mb temperatures. Note how the cold begins in the Arctic and plunges all the way down to the Gulf coast. This is the first step in triggering our storm. 

As the big cold dome bulldozes its way into the U.S., the temperature contrast between the cold and Gulf warmth creates a baroclinic boundary. Overrunning is a typical thing that can happen in any season, but in this case, the extreme nature and scale of the cold means it won't take much to trigger a truly massive overrunning setup. 

Above: explanation of overrunning generally. Image courtesy of PNI Atlantic News. 

Our trigger goes off on Friday, and then it's off to the races. 

Now, many will ask at this point: "we're expecting Arctic air this weekend, won't that make it too cold to snow?"

Normally, this kind of Arctic dome would be suppressive, and early on, the models (interestingly not the AI though) believed that this would be the case. However, there's more to this story. Yes, it looked like the cold press would be too much, but then we started seeing a trend at 500mb. 

Above: European ensemble trend at 500mb. This is looking at the last couple days of runs. 

It's subtle, but look at the energy over the southwest, and the energy in the northern Plains. Initially, the models on balance had these separated, creating more confluence over our region. That would have zipped this storm along and out to sea. However, the trend has emphatically tried to phase these two pieces. This is where the explosive potential for us comes into play, because if there is a full phase it triggers a bit coastal storm. 

However, as it stands the imperfect interaction between these pieces of energy pumps heights in the east, forcing a further north track of a relatively weak coastal storm. The storm is enhanced by the overall setup. It doesn't need the phase to produce a major event from the south to Maine. 

Below is the trend as we've seen the changes at 500mb. Big, big changes. 

Current Thoughts
With this change at 500mb across the guidance, there is higher than usual confidence that a major winter storm will hit the state. In fact, there is a cross guidance signal now that even puts some very robust totals in play on the ensembles. While a full phase would up the ante even more, the setup as it stands is high end. 

Timing

• The current expectation is that the snow starts in the predawn hours on Sunday. 
• The worst of the storm is possibly Sunday afternoon-Sunday night, with snow ending Monday morning or afternoon.

Snow accumulation

• Double digit snow statewide is increasingly likely.
• It's still too early for specific numbers, but this looks to be a higher end snowfall.

Impact

• The national scope of the storm means that there will be major travel disruptions from the weekend into early next week. 
• This looks like a high impact event in Connecticut with widespread cancellations Sunday and Monday. 
• Wind and power outages look to be low risk at this time. 

To be clear, nothing is fully locked in at this time. While a storm is likely, there is still room for this storm to shift north, which could introduce mixing in southern CT after an initial thump of snow, or the storm could shift south, reducing totals. There's also the chance of more phasing of the two pieces of energy, which would raise the snow potential even more. 

The bottom line is that a blockbuster storm is on the table for much of the east, and between the Sunday snow and Arctic blast this weekend, we have a highly disruptive period on tap. 

​A​s always, please like, share, and interact with us on our social media--on Facebook to share our discussions, and follow us on Twitter @southernctwx to retweet our posts. Hit the buttons below to join.
​
Thank you for reading SCW.

​-DB

Good evening from Southern Connecticut Weather! 

I'm pretty exhausted, and we have a very active week ahead, but we need to grade the two systems that impacted CT over the previous weekend. Let's get right to it, starting with the Sunday-Monday event. 

Above: the verification map from the Sunday-Monday winter storm. These use the NWS observations and the locations are approximate. 

Timing
Well, starting from the top, timing was definitely tricky. We said that light to moderate snow would break out from SW to NE, and that it would arrive between 6-9am. That was spot on. We predicted that there would be two parts of the storm, and the original expectation was that the second part would begin around 2-3pm.

We adjusted later in the day based on the data, but we don't get points for any new information after we post the final forecast. Part two started in earnest between 5-6pm. The snow was heaviest between 5-10pm, and accumulating snow did end in the predawn hours, though snow did continue until about 8-9am. We lose a little points there. While we did miss the start of part two, the rest of the forecast was very good. 

Grade: B+

Snow & Ice Accumulation
If you read through the comments during the day, you'd think that the storm ended in the afternoon. There was a lot of angst about snow totals. So much so that even I was a bit worried. Living in central CT, I went to bed well below what would've been an acceptable miss, but wouldn't you know, the storm was not over. As expected.

Looking at the map above, there are a few takeaways. First, I'm very glad I did not go with a broad 4-8" zone. Phew.

Second, while there were certainly spots that ended below the forecast, most were right where we thought they would be. Windsor looks like the big "loser" with under two inches of snow and one follower reporting virtually nothing. In hindsight, I suppose pulling the 2-4" zone further east would have worked, but given the data we had at the time, I don't think that would have been prudent. This was a good map, despite some spots being lower than the forecast. That said, I don't like central CT ending where it did. 

This is a classic case of WAIT UNTIL THE STORM IS ACTUALLY OVER BEFORE CALLING BUST. 

Grade: B+

Wind & Power Outages
This was fairly easy. We had some wetter snow that made everything picturesque, but it wasn't enough to cause issues. No wind, no outages. 

Grade: A

Overall Impact
The forecast called moderate to high impact on the roads during the more snowy parts of the day, and lesser impact during the lull due to temperatures. That was accurate. Monday started slick but ended up fine, and we expected a moderate impact event, which seemed accurate overall.

Grade: A 

Final Grade
For all of the worry in the comments yesterday, the forecast was pretty dang good. We love to see it. Let the storm finish first, folks. 

Final Grade: B+

​On to the next one. 

Above: the verification map for the Saturday event. 

Timing
For this one, we were generally right. Snow did break out between 2-6am, and it took a while for precipitation to get to eastern CT, but my goodness. SE CT needed to wait an eternity for precipitation to start, and by waiting so long they ended up torching with some areas near 40 degrees during the storm. That's not good, because the timing impacted the forecast. 

We had the timing of the two batches covered, but missing the timing in eastern and SE CT was not acceptable. 

Grade: C

Snow & Ice Accumulation
In the 2-5" zone we expected things to be all snow. That was right. If anything, the 2-5" zone could have been pulled to far north central CT, and upped to 3-6". So overall, not the best. The snow overperformed expectations. 

In the 1-3" zone we did well, with the exception of the aforementioned north central CT area. This area remained all snow despite the lull, with light non-accumulating snow.  

The C-2" zone was the trickiest. While snow did fall in much of the zone, there wasn't even a coating in probably 1/3 to half of the zone. Even when the floor is as low as you can go, not getting anything is bad. It was a very interesting distribution, with part of the state overperforming and another part of the state underperforming. 

Grade: C 

Wind & Power Outages
It would have been nice to grade this, since this was easy and we nailed it. But I said we wouldn't grade it here for that reason. Let's not have a grade inflation scandal, here.  

Overall Impact
Fortunately, the best part of the forecast was judging the overall impact. It was more impactful in NW CT, somewhat impactful in central and SW CT, and low impact in the C-2 zone.

Grade: A

Final Grade
Overall, this was pretty disappointing. The more visible event doing better helps ease the sting, but missing the timing in SE CT and both over and under forecasting snow in the same storm is not where we want to be. 

Final Grade: C+

A​s always, please like, share, and interact with us on our social media--on Facebook to share our discussions, and follow us on Twitter @southernctwx to retweet our posts. Hit the buttons below to join.
​
Thank you for reading SCW.

​-DB