The Clipper today caught many off guard. Here, I want to briefly summarize the storm, first analyzing the forecast passed along to Premium subscribers to show what was expected today, what wasn’t, and what should have been. Superintendents were put in an incredibly difficult place by a Clipper that caught many off guard, especially as the National Weather Service refrained from issuing any forecast products. Though the storm admittedly was under Winter Weather Advisory criteria, a Hazardous Weather Outlook issued the night before could have helped raise attention to a storm that caused numerous travel headaches at the worst possible time.
The final Premium forecast, issued at 11 PM last night, read this:
The going forecast is for up to 1 inch of snow in Westchester County, with half an inch to an inch and a half likely in Fairfield County, and 1-2 inches likely in New Haven County. The timing has sped up, so that snow breaks out between 6 and 7:30 AM across the area with the heaviest snow between 8 and 9 AM. The snow then will leave the area between 9 and 10:30 AM, with all snow over across all counties by 11 AM at the latest.
Upon verification, almost this entire forecast verified. The snowfall amounts were slightly underdone, as multiple areas in Westchester County reported between 1 and 1.5 inches, as did multiple locations in Fairfield County, and a few locations in New Haven County reported over 2 inches, but generally the storm over performed by just a few tenths of an inch. Certainly not enough to make a really sizable difference. The forecast was also correct that the storm sped up. Snow broke out across the region in exactly the timeframe specified, and it ended exactly between the timeframe specified. There was only one key problem, the target timeframe for heaviest snow was 8-9 AM, when this morning, for western Fairfield County, it ended up being 7-8:30 AM, as the heaviest snow was at the front end of the band moving through, not near the middle or back end as most models showed. The difference in this timing was a matter of half an hour or 45 minutes, certainly within the margin of error for our weather models and any standard forecast issued 7-8+ hours before main impacts, but enough to make a sizable difference, as that front-end burst of snow was heavy enough to cause travel conditions to go downhill by 7:30 AM in most of the region when it was expected they would not be really bad until 8 or 8:30 AM. Similarly, many roads did not appear to be properly treated, meaning that snow stuck immediately and piled up rapidly, resulting in worse road conditions than expected as well. It was this confluence of events that resulted in a chaotic morning.
The final school impact forecast also emailed to Premium subscribers last night at 11 PM is attached below:
New Haven County: 25% delay, 30% closure (inland) 15% delay 20% closure (coast)
Fairfield County: 20% delay 25% closure (inland) 15% delay 20% closure (c0ast)
Westchester County: 20% delay 20% closure (inland) 15% delay 15% closure (coast)
All in all, this was a decent forecast. We saw a couple delays/closures in inland Westchester closure, but not enough to warrant above 20% in either category. No coastal districts were impacted, so the low percentages there were warranted, though they could have been lower. The same is true for Fairfield County. Many districts tried to delay inland but ended up having to close, showing that the closure forecast was accurate. Still, only a little more than half of districts inland were impacted, in line with a 45% combined percentage of school impacts in Fairfield County. The closure percentage should have been slightly higher to show how severe impacts would be, but this was again very close. Coastal districts saw no impacts, so it was the correct call to have lower percentages at the coast, but they likely could have been a little lower. Still, conditions in some coastal districts were probably close enough to warrant impacts that these were reasonable. And again in New Haven County, many schools that delayed ended up having to close, especially as snow lasted slightly longer there. Overall, the inland percents were a little low, and the coastal percents were a little high, but hopefully this does demonstrate that there were expected school impacts from the storm, despite many saying the poor road conditions in the morning were “unexpected.”
What this storm did do, however, is put superintendents in a very difficult position. I think the best-case scenario may have been modified 3-hour delays for most inland districts, as that would have allowed schools to open and allow time for most roads to be cleared. To do that, however, these districts would have needed advance forecasts, and even though the one I produced above was quite close for this storm, it was very low confidence because of how the Clipper acted. Within 12 hours of the storm models showed a range of half an inch to 3 inches of snow, and thus the potential impacts were similarly uncertain. This was a very complex little storm, and so I actually side with superintendents in most decisions here, as they were placed in a nearly impossible situation. Close for an inch or inch and a half of snow, open on time when roads are decent but going downhill and snow is falling heavily, or delay for when roads are covered in snow and snow is lighter and beginning to end. There really is no good decision, and though the safer option was to close (and was certainly the right call far inland), there were many borderline regions where almost any decision could be defensible from a weather standpoint. I maintain that delays likely were the least correct decision due to the timing of the system, but in some further west areas into Westchester County they did work because of the slightly quicker nature of the storm. It was a combination of a lack of proper awareness ahead of the storm and a low confidence forecast (as forecasts always seem to be with these Alberta Clippers) that led to almost a perfect storm for trouble with the morning commute and school decisions. So, although this can be rare, I do sympathize with many scrambling superintendents today, as many likely received inaccurate forecasts from weather services that focus too broadly to nail a small-scale feature like this.
Sadly for many superintendents, but to the pleasure of numerous students across the region, there could be a similarly difficult decision on Monday. A mixture of snow, sleet, freezing rain, and plain rain look likely across the region throughout the day. The timing and exact impacts are still being nailed down, but a preliminary outlook has already been given to Premium subscribers. Subscribers will receive school percentage chances of closures, delays, and early dismissals tomorrow along with an early release of the official forecast, so if you’re interested in receiving forecasts like the one I listed above, do sign up here. You can also just buy the detailed first look at the two storms next week and the long-range SWCT forecast here, though more detailed and specific updates will be available for purchase tomorrow and Sunday as well. When subscribed, you will be emailed any forecast updates, and the first to know the likelihood of any and all school closures across the region. And with school impacts possible Monday and a chance of a snow storm late next week, there is no better time to be aware of the way weather is going to impact your life. Free updates will come detailing the forecast on Sunday as well, so either way, be sure to keep it here for the latest as winter weather bears down on the region.