Fluke? Farmer's almanac predicted rare Lowcountry snow last week — and more on the way

Sitting at the very top of the Old Farmer’s Almanac’s long-range weather forecast for Jan.1 to 7 in the Southeast region are six words that proved oddly prophetic.

“Rain to snow, then sunny, cold.”

The words seem to describe, albeit briefly, exactly the weather Beaufort County faced during the first week of 2018 when it saw 3 to 5 inches of snow. But was it a fluke? How accurate is the long-range forecast of the Old Farmer’s Almanac? If it is accurate, when should we expect our next blast of winter weather?

According to the Old Farmer’s Almanac website, their long term predictions are made 18 months in advance. That would mean that the forecast that seemingly nailed last week’s weather was written in July of 2016. The Almanac claims an 80 percent accuracy rate. Their competitor, simply named The Farmer’s Almanac, makes similar accuracy claims.

How do they know if they’re right?

Sarah Perreault, senior editor of Old Farmer’s Almanac, explained how accuracy is determined by her publication.

“So we’ve got this span of Jan. 1 to 7, and during that span you can expect rain, snow, sunny and cold. Maybe on Jan. 2 it wasn’t sunny, but it was sunny on the 5th, 6th and 7th. That’s a win for us,” said Perreault.

The Farmer’s Almanac’s managing editor, Sandi Duncan, says that her publication’s accuracy reports come from third parties, but that they do share their biggest hits and biggest misses with the public at the end of each year.

Both almanacs issue forecasts for vast geographical areas. The region containing Beaufort County in the Old Farmer’s Almanac covers South Carolina, North Carolina and Georgia. Our region in The Farmer’s Almanac covers those states and six more.

According to Perreault, another way that accuracy is verified for the Old Farmer’s Almanac is by seeing how prevalent a predicted weather pattern is in the region where it is forecast. For instance, if it had only snowed in one small piece of our region last week, instead of blanketing most of it, then that forecast would’ve been inaccurate.

How do they do it?

Some of the methods used by the Old Farmer’s Almanac in their long-range forecasts date back to 1792, according to their site. Almanac founder Robert B. Thomas thought that sun spots influenced weather on earth, and the Old Almanac still studies sun spots as part of its forecasting model. It also looks at climatological data on prevailing weather patterns and meteorological data about the atmosphere. The specific formula is locked in a black box, according to Perreault.

Meanwhile, The Farmer’s Almanac looks at sun spots, the positions of the planets, the tidal effects of the moon and a variety of other factors, with the exact formula only known by a single forecaster who goes by the pseudonym Caleb Weatherbee. Their site proudly boasts that they don’t use any modern weather tracking, including computers or satellites.

This is a very different approach from the Old Farmer’s Almanac, which has integrated state-of-the-art technology into their forecasting work, alongside the methods of old.

“We have more and better data than ever before,” said Perreault. “The more information you have, the better off you are, I believe.”

A reason for skepticism

According to James Carpenter, meteorologist with the National Weather Service in Charleston, being as accurate as these almanacs claim to be is beyond current forecasting capabilities, especially when predicting so far in advance.

“What we observe with human models and computer forecasting is that skill declines with time, and you notice a dramatic decrease in forecast skill after about five days,” said Carpenter. “So at least from data and observation and analysis that I’m familiar with, an 18-month, 80 percent accuracy is most likely sheer luck, and seems unsustainable.”

Cary Mock, a professor of climatology and meteorology at the University of South Carolina, said that while the public has been fascinated with almanacs for a long time, they don’t apply “any science or logic to weather.”

Modern meteorology has a generous number of skeptics, and even almanac editors will give scientific methods an edge over their own work in some regards.

“Farmer’s almanacs are never going to replace your local meteorologists. We’re not that localized,” said Duncan. “Our real niche is that we’re giving you a forecast for three months, six months, or a year from now.”

Duncan said that forecasting so far out allows people to plan for weddings or vacations, or for business needs if they are in a line of work affected by the weather, but stressed that almanacs were never meant to compete with modern meteorology.

Apples and oranges

Perreault said that the service the Old Farmer’s Almanac provides should be seen as something more akin to a climate forecasting than a weather report.

“We’re doing weather trends rather than day to day predictions,” said Perreault.

According to Carpenter, predicting climate trends is in no way similar to the forecasts you’d expect to see on the evening news.

“There is a difference between weather forecasting and climate forecasting,” said Carpenter. “I can say, for example, that next January is going to be much colder than this coming July, and odds are my prediction is going to be accurate, but we’re not discussing weather forecasting, we’re discussing climatology.”

So, when will we see snow again? The weather service in Charleston can’t say.

If the Old Farmer’s Almanac is right, though, Beaufort County residents would be wise to start planning for snow around Feb. 1 through 6, when it is calling for “rain to snow, then sunny, very cold.”

This story was originally published January 10, 2018 at 4:53 PM with the headline "Fluke? Farmer's almanac predicted rare Lowcountry snow last week — and more on the way."