With a pattern shift looming, snow hype will start flying.
Heading Off Weather Hype
Those that have followed me for a while know that I attempt to combat the weather hype that so often sensationalizes weather reporting. I do not do this out of spite for other meteorologists, but only to give clear, actual information on the uncertainties in the weather, especially when the hyped up event is still days away.
I think, over the past couple of years, there has been an improvement overall and hype has decreased somewhat. Still, I like to try to head off the hype before it really starts to get going. Once I start to get a couple of questions about an event, it is time to clear the air for everyone.
Major Pattern Shift Next Week
The weather has been tranquil across the Finger Lakes for weeks. Temperatures have been near or above normal and precipitation has been limited.
It seems often enough, however, that by Thanksgiving, the weather starts to take a turn towards winter. That will be the case this year as a prolonged period of below normal temperatures seems likely starting early next week.
One way to gauge the validity of a pattern shift is to look at the ensembles of the computer weather models. The ensembles are a set of model runs where each run has slight different conditions programmed into the computer. These differences may be in the form of different equations to model the weather or different sets of current data that the model uses to make its predictions. For the European model, which is consistently the most accurate model in the world, the ensemble set contains 51 different model versions.
Each time the model runs, there are 51 different model forecasts to look at, which gives forecasters a range of possible outcomes to consider. In theory, the actual weather will fall somewhere within the range of possibilities, likely near the average. Often times that is the case, but the ensembles can certainly be wrong, just like any other computer model.
The ensembles of the Euro (which I am not able to show graphically due to copyright restraints), on average show daily high temperatures consistently in the 30s starting Sunday and persisting through the end of November. The upper range of temperatures is mostly in the 40s and low 50s. To me, this shows a pretty good agreement that most days will have below normal temperatures through the end of November.
How About Snow?
Picking out a long range trend in temperatures is not terribly difficult. Picking out a major snow event five days in advance, especially at the very start of the winter season, is much more difficult.
The focus of any snow hype over the next couple of days will be Sunday night into early Monday. The storm system that will usher in this pattern shift has some potential to bring snow to the Finger Lakes. How much snow? That is anyone’s guess at this point.
Looking at those same 51 members of the European ensemble suite, there is a wide range of possibilities. Using Ithaca as a reference point, about 40% of the ensemble members show a few inches of snow on the order of 2-6 inches. The other 60% of ensemble members are split just about evenly between nearly no snow, a moderate (6-9″) snow event, and a significant event (over 9″). Some of the ensemble members recently have been extreme, showing upwards of 30″ in parts of the region.
This is where forecasting experience comes into play. Sorting through the extreme range of possibilities is what meteorologists must do every day, for the models often show a very wide range of possibilities.
Even though the ensembles may show about a 40% chance of six or more inches of snow, I am very comfortable saying the chances are much less. I won’t say it is impossible, because the weather can always surprise, but the computer models very often overplay snow accumulations early in the season. This is especially true with temperatures right near freezing, which is where the European shows temperatures Sunday night.
So, beware of the hype, remember that uncertainty is high for snow accumulations, especially early in the season, and stay tuned to Finger Lakes Weather for No Hype snow forecasts all winter long.
Really…this blog post was partly just an excuse to use a meme for a header image. I don’t even watch Game of Thrones…but the ‘Winter is Coming’ meme is just dying to be overused by meteorologists! 🙂