Good afternoon from Southern Connecticut Weather.
There wasn't a lot of sleep in the last few weeks as winter gave us its best shot. This latest storm was the most impactful, with snow, ice, rain, and wind on the backside of it. How did our forecast hold up? We submit our final grade below, and illustrate why the social media hype you may have seen elsewhere for a possible storm on Thursday took off...and was wrong.
There wasn't a lot of sleep in the last few weeks as winter gave us its best shot. This latest storm was the most impactful, with snow, ice, rain, and wind on the backside of it. How did our forecast hold up? We submit our final grade below, and illustrate why the social media hype you may have seen elsewhere for a possible storm on Thursday took off...and was wrong.
Above: the verification map for the winter storm. Note that this includes measured snow and sleet (which officially counts as snow) from published National Weather Service reports.
Grading the Forecast
Timing
As I mentioned in the final call forecast, the timing was trickier than I would have liked, both for the start time and the evolution of the warm air. We were fortunately right that the morning and afternoon would be fine, so that's good, but the onset of the snow happened fast.
We had snow break out from 3-7pm. First flake reports started coming in at 2:30pm, which isn't bad but worth a minor deduction. What was the bigger issue with start time was that the snow rapidly moved across the state, hitting eastern CT faster than expected. Many were snowing by 5pm, so this range was too large.
Now for the changeover to mixing. We did say that we expected mixing to occur in SW CT between 10pm and midnight, and the mixing happened between 9-10pm. Not bad. Not perfect. However, we did also say that most of southern CT would be rain by early Sunday morning. That was partly right--but there wasn't enough specificity about it.
For northern CT, we were spot on, even identifying the potential for a mesolow to lock in colder air. We were also spot on about the rain timing window and wind timing.
As mentioned above, there needed to be some deduction for a faster onset of the snow and slower erosion of the cold in part of southern CT, but this was pretty good overall.
Grade: A-
Snow & Ice Accumulation
As you saw with the accumulation map above, we were spot on. It was the best map of the season, and the fact that this was the highest impact and most tricky forecast makes me proud. I'm even proud of where we set up the dividing line, though I probably could have pushed it slightly north.
We had plenty of cold to start as snow, and as expected the warm air aloft did erode the cold. The surface cold was hardest to dislodge in northern CT, and NW CT struggled along with much of northern CT to get above freezing. However, there was much more cold than expected in southern CT away from the immediate coast, and as a result there was more freezing rain there.
For southern CT, we did anticipate a general 1-3" of snow and sleet, along with a glaze of freezing rain before a flip to rain. It would have been more helpful to be more specific with the freezing rain amounts, because as I look back, a glaze implies minimal icing and that was not the case. The trick here is, what's significant? For me, .1 or .2 of ice is essentially a glaze to me, while .25 and above is more meaningful. It's something to remember whenever we have another icing event on the table.
For northern CT, the guidance was all over the place but we went with 2-5 rather than 2-4" or a general 1-3 statewide. Great call. As expected, few saw 5", but the high ceiling for a colder storm turned out to be right as we had an isolated number of reports above 5". What's most important in all of this is that I did communicate that ice, not snow, was the story of this storm.
The map carries us here, which is all that folks care about I know. However, there needed to be some deduction for lack of clarity. I'm not sure we could have anticipated the amount of cold in southern CT at the time of the forecast given the data we had, but to our credit, we did put it in multiple live updates in advance of the storm--so it should not have been as much as a surprise to readers.
Grade: A-
Wind & Power Outages
It was a good call saying that we wouldn't have many wind issues during the storm. That proved to be right given the wind reports we saw. We got our significant wind in the wake of the storm and today. Because of the ice, we saw isolated to locally scattered outages. While overall, we had maybe 1-2% of the state without power--isolated overall--we did have some communities with higher concentrations of outages. That worked well with the forecast.
Not much else to add here. It was spot on.
Grade: A
Overall Impact
This is another bright spot for the forecast. I considered saying that this would be moderate impact in southern CT, but stayed away from that given the colder storm potential and forecast this as a high impact event statewide. We had numerous events canceled during the weekend, and the combination of snow, sleet, freezing rain, and heavy rain causing localized flooding did make things a mess. The road conditions were mostly right--though I should have called for more icy roads into the morning in southern CT. Great job overall.
Grade: A
Final Grade
You have no idea how good it does my heart to know that the toughest storm of the season so far had the best forecast of the season. On little sleep!
Yes, there are always ways that we can improve. That is why we do these reviews. There is no perfect forecast. I could have been more specific with expected freezing rain accumulations, and the onset timing could have been forecasted better, but everyone that read the final call forecast knew to expect a high impact event statewide Saturday and Sunday.
Although it doesn't get graded, the live updates continue to prove that they add enormous value, given that we needed to "nowcast" the erosion of the cold and several waves of precipitation. For once, having the snow accumulation forecast weighed twice helps rather than hurts the final grade!
Final Grade: A-
Now let's talk about something not so good--the social media hype surrounding the next storm in the pipeline...
Grading the Forecast
Timing
As I mentioned in the final call forecast, the timing was trickier than I would have liked, both for the start time and the evolution of the warm air. We were fortunately right that the morning and afternoon would be fine, so that's good, but the onset of the snow happened fast.
We had snow break out from 3-7pm. First flake reports started coming in at 2:30pm, which isn't bad but worth a minor deduction. What was the bigger issue with start time was that the snow rapidly moved across the state, hitting eastern CT faster than expected. Many were snowing by 5pm, so this range was too large.
Now for the changeover to mixing. We did say that we expected mixing to occur in SW CT between 10pm and midnight, and the mixing happened between 9-10pm. Not bad. Not perfect. However, we did also say that most of southern CT would be rain by early Sunday morning. That was partly right--but there wasn't enough specificity about it.
For northern CT, we were spot on, even identifying the potential for a mesolow to lock in colder air. We were also spot on about the rain timing window and wind timing.
As mentioned above, there needed to be some deduction for a faster onset of the snow and slower erosion of the cold in part of southern CT, but this was pretty good overall.
Grade: A-
Snow & Ice Accumulation
As you saw with the accumulation map above, we were spot on. It was the best map of the season, and the fact that this was the highest impact and most tricky forecast makes me proud. I'm even proud of where we set up the dividing line, though I probably could have pushed it slightly north.
We had plenty of cold to start as snow, and as expected the warm air aloft did erode the cold. The surface cold was hardest to dislodge in northern CT, and NW CT struggled along with much of northern CT to get above freezing. However, there was much more cold than expected in southern CT away from the immediate coast, and as a result there was more freezing rain there.
For southern CT, we did anticipate a general 1-3" of snow and sleet, along with a glaze of freezing rain before a flip to rain. It would have been more helpful to be more specific with the freezing rain amounts, because as I look back, a glaze implies minimal icing and that was not the case. The trick here is, what's significant? For me, .1 or .2 of ice is essentially a glaze to me, while .25 and above is more meaningful. It's something to remember whenever we have another icing event on the table.
For northern CT, the guidance was all over the place but we went with 2-5 rather than 2-4" or a general 1-3 statewide. Great call. As expected, few saw 5", but the high ceiling for a colder storm turned out to be right as we had an isolated number of reports above 5". What's most important in all of this is that I did communicate that ice, not snow, was the story of this storm.
The map carries us here, which is all that folks care about I know. However, there needed to be some deduction for lack of clarity. I'm not sure we could have anticipated the amount of cold in southern CT at the time of the forecast given the data we had, but to our credit, we did put it in multiple live updates in advance of the storm--so it should not have been as much as a surprise to readers.
Grade: A-
Wind & Power Outages
It was a good call saying that we wouldn't have many wind issues during the storm. That proved to be right given the wind reports we saw. We got our significant wind in the wake of the storm and today. Because of the ice, we saw isolated to locally scattered outages. While overall, we had maybe 1-2% of the state without power--isolated overall--we did have some communities with higher concentrations of outages. That worked well with the forecast.
Not much else to add here. It was spot on.
Grade: A
Overall Impact
This is another bright spot for the forecast. I considered saying that this would be moderate impact in southern CT, but stayed away from that given the colder storm potential and forecast this as a high impact event statewide. We had numerous events canceled during the weekend, and the combination of snow, sleet, freezing rain, and heavy rain causing localized flooding did make things a mess. The road conditions were mostly right--though I should have called for more icy roads into the morning in southern CT. Great job overall.
Grade: A
Final Grade
You have no idea how good it does my heart to know that the toughest storm of the season so far had the best forecast of the season. On little sleep!
Yes, there are always ways that we can improve. That is why we do these reviews. There is no perfect forecast. I could have been more specific with expected freezing rain accumulations, and the onset timing could have been forecasted better, but everyone that read the final call forecast knew to expect a high impact event statewide Saturday and Sunday.
Although it doesn't get graded, the live updates continue to prove that they add enormous value, given that we needed to "nowcast" the erosion of the cold and several waves of precipitation. For once, having the snow accumulation forecast weighed twice helps rather than hurts the final grade!
Final Grade: A-
Now let's talk about something not so good--the social media hype surrounding the next storm in the pipeline...
Above: one of the images that was circulating social media in recent days about the possibility of a historic storm this week. On this image, "snow potential" was for Hartford to have nearly 35" of snow by Friday! Oops.
Hype Sells but is Often Wrong
SCW has built its reputation on no-nonsense weather forecasting and discussion, and as a practice, we don't take shots at others that forecast. It's hard stuff. We don't pay attention to what anyone else is doing really, with the exception of the National Weather Service because they issue watches and warnings (and have high resolution models that are helpful).
However, we often quietly bat down the hype that we see on social media. When talking about hype here, we're not talking about a bad forecast--which happens. We're talking about people that are intentionally trying to rile people up and/or share information in bad faith.
This time, I want to take a look at why the image above and the other calls you may have seen for an epic event coming this week turned out to be wrong, and why at each step better decisions could have been made.
The Hype Cycle
Step 1: Find the Kernel of Truth
Like most garbage on social media, it probably has some kernel of truth--or at least the appearance of it. If you've been following our forecasts, we noted on Friday, February 14, that there was storm potential for the coming week. We kept it vague as we usually do at this time range, because while you can see storm potential 6-10 days out, you cannot see details.
This is what we said in the final call forecast that we issued that Friday:
There will be plenty of cold, which will lead us to the next storm in the pipeline.
There is zero reason to get excited about or dread a possible storm next week. At this time, we do have higher than usual confidence that something will develop. Because there is going to be cold air in place and likely blocking in the Atlantic, we know it is highly unlikely to cut like this weekend storm. We have moderate confidence that the timing for a storm would be late Wednesday or Thursday. We do not know track and storm evolution. This could easily miss because of a poorly timed phase--just like that blizzard we missed out on a month ago. This could be a messy phase that brings us another modest snowfall. It could be a big dog blizzard. There's no real reason to do anything other than look at next week with a casual eye and avoid the hype on social media and elsewhere. Let's see where we are Sunday before taking anything related to next week seriously.
We intentionally don't show snow maps or the most extreme versions of these models because they are useless. A good forecaster knows not to use them--especially at this range.
The signal that a storm likely developing somewhere was the kernel of truth. But that's not enough to go all in on a historic event.
Step 2: Show Extreme Potential
Sometimes, there is legitimately extreme potential that should be communicated. Most of the time however, models are either over amplified or "overwhelmed" in analyzing the nuances and chaos of numerical weather prediction at longer or even medium range. They start out extreme, but naturally modify to something far more mundane more often than not.
Here, a good forecaster knows to wait to see if there's a shift in the fundamental elements of a forecast that make an extreme solution more or less likely. In our text above, we note the potential of a poorly timed phase or a messy phase, along with the big dog possibility (but note we don't talk about snow totals intentionally). We don't post a snow map with specific numbers and say it's not a forecast. In our opinion, sharing that kind of stuff does more harm than good, and should only happen when you're at high confidence for an event to hit.
For others, those more likely scenarios don't get serious consideration. So what was a kernel of truth--a big storm is possible--gets twisted into the most extreme computer model run possible and becomes the only thing that is shared and seen because it's shocking to look at.
And the result is what we would expect.
Hype Sells but is Often Wrong
SCW has built its reputation on no-nonsense weather forecasting and discussion, and as a practice, we don't take shots at others that forecast. It's hard stuff. We don't pay attention to what anyone else is doing really, with the exception of the National Weather Service because they issue watches and warnings (and have high resolution models that are helpful).
However, we often quietly bat down the hype that we see on social media. When talking about hype here, we're not talking about a bad forecast--which happens. We're talking about people that are intentionally trying to rile people up and/or share information in bad faith.
This time, I want to take a look at why the image above and the other calls you may have seen for an epic event coming this week turned out to be wrong, and why at each step better decisions could have been made.
The Hype Cycle
Step 1: Find the Kernel of Truth
Like most garbage on social media, it probably has some kernel of truth--or at least the appearance of it. If you've been following our forecasts, we noted on Friday, February 14, that there was storm potential for the coming week. We kept it vague as we usually do at this time range, because while you can see storm potential 6-10 days out, you cannot see details.
This is what we said in the final call forecast that we issued that Friday:
There will be plenty of cold, which will lead us to the next storm in the pipeline.
There is zero reason to get excited about or dread a possible storm next week. At this time, we do have higher than usual confidence that something will develop. Because there is going to be cold air in place and likely blocking in the Atlantic, we know it is highly unlikely to cut like this weekend storm. We have moderate confidence that the timing for a storm would be late Wednesday or Thursday. We do not know track and storm evolution. This could easily miss because of a poorly timed phase--just like that blizzard we missed out on a month ago. This could be a messy phase that brings us another modest snowfall. It could be a big dog blizzard. There's no real reason to do anything other than look at next week with a casual eye and avoid the hype on social media and elsewhere. Let's see where we are Sunday before taking anything related to next week seriously.
We intentionally don't show snow maps or the most extreme versions of these models because they are useless. A good forecaster knows not to use them--especially at this range.
The signal that a storm likely developing somewhere was the kernel of truth. But that's not enough to go all in on a historic event.
Step 2: Show Extreme Potential
Sometimes, there is legitimately extreme potential that should be communicated. Most of the time however, models are either over amplified or "overwhelmed" in analyzing the nuances and chaos of numerical weather prediction at longer or even medium range. They start out extreme, but naturally modify to something far more mundane more often than not.
Here, a good forecaster knows to wait to see if there's a shift in the fundamental elements of a forecast that make an extreme solution more or less likely. In our text above, we note the potential of a poorly timed phase or a messy phase, along with the big dog possibility (but note we don't talk about snow totals intentionally). We don't post a snow map with specific numbers and say it's not a forecast. In our opinion, sharing that kind of stuff does more harm than good, and should only happen when you're at high confidence for an event to hit.
For others, those more likely scenarios don't get serious consideration. So what was a kernel of truth--a big storm is possible--gets twisted into the most extreme computer model run possible and becomes the only thing that is shared and seen because it's shocking to look at.
And the result is what we would expect.
Above: this was the extreme GFS operational model forecast for total snow by this Friday. This model run was 7.5 days in advance of Friday. This much snow in one storm is almost unprecedented, which is a red flag in itself.
Here's a trend loop for that same snapshot in time. Look at how the snow forecast changes as we get closer to reality. It's basically zero now. Note that some of this included snow from the weekend storm, but the picture is all the same.
Here's a trend loop for that same snapshot in time. Look at how the snow forecast changes as we get closer to reality. It's basically zero now. Note that some of this included snow from the weekend storm, but the picture is all the same.
Step 3: The Truth Arrives Too Late
By the time someone is sharing a computer model showing 35" of snow in a week, or a hurricane hitting New Haven, or super high end tornado parameters in Connecticut, real analysis and truth go into hiding. We're playing whack-a-mole with questions about what's actually going to happen.
Eventually the truth arrives because there's no mega blizzard, or hurricane, or tornado outbreak, but not before a lot of people are left confused and concerned.
One of the fundamental things about weather forecasting is understanding that most people do not follow it the same way that we do. Concepts like phasing, tropospheric polar vortex, and teleconnections are not understood at a detailed level by a small business owner or family, nor should they be. It's our job to bring thoughtful analysis to the table to help people be informed.
Just looking at the 500mb pattern should have told many that the mega blizzard idea up the Eastern Seaboard was going to be tough, especially if folks waited for more information.
By the time someone is sharing a computer model showing 35" of snow in a week, or a hurricane hitting New Haven, or super high end tornado parameters in Connecticut, real analysis and truth go into hiding. We're playing whack-a-mole with questions about what's actually going to happen.
Eventually the truth arrives because there's no mega blizzard, or hurricane, or tornado outbreak, but not before a lot of people are left confused and concerned.
One of the fundamental things about weather forecasting is understanding that most people do not follow it the same way that we do. Concepts like phasing, tropospheric polar vortex, and teleconnections are not understood at a detailed level by a small business owner or family, nor should they be. It's our job to bring thoughtful analysis to the table to help people be informed.
Just looking at the 500mb pattern should have told many that the mega blizzard idea up the Eastern Seaboard was going to be tough, especially if folks waited for more information.
Above: the last 15 runs of the GFS model looking at the overall pattern at 500mb. Note all of the changes that happen run to run--these make a huge difference in what happens here.
Ok, so what's happening this week?
Now for some reality.
A mega blizzard is not happening this week--though you probably know that by now because there aren't any new computer models showing a blizzard being shared. The kernel of truth was in fact truth--a significant storm is likely to form, but because of a missed connection between the northern stream and southern stream of the Jet Stream, the storm slides well south of our region, and becomes a significant storm well out to sea.
As a result, the next storm in the pipeline is most likely a miss--with light snow on Thursday possible if an inverted trough develops. This gives us all a much needed break from stormy weather, though the Arctic cold will be with us for most of the week ahead. The pattern still looks active, but for now, not at the same pace as the last two weeks.
The storm was real. The hype was wrong.
As 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
Now for some reality.
A mega blizzard is not happening this week--though you probably know that by now because there aren't any new computer models showing a blizzard being shared. The kernel of truth was in fact truth--a significant storm is likely to form, but because of a missed connection between the northern stream and southern stream of the Jet Stream, the storm slides well south of our region, and becomes a significant storm well out to sea.
As a result, the next storm in the pipeline is most likely a miss--with light snow on Thursday possible if an inverted trough develops. This gives us all a much needed break from stormy weather, though the Arctic cold will be with us for most of the week ahead. The pattern still looks active, but for now, not at the same pace as the last two weeks.
The storm was real. The hype was wrong.
As 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
