Farmer’s Almanac? Our snowman begs to differ
The late October storm that struck much of New England with wind-driven snow and accompanying power outages was enough to stir up unpleasant memories of last winter’s rigors. But just what this winter has in store remains a matter of debate among weather experts, who say the Northeast is a tough area for accurate long-range forecasting.
One local longtime forecaster, Marshfield resident Robert Pannuto, says area residents fearing another blizzard-filled winter can rest easy: He predicts that less than the usual 41-inch average will fall.
Pannuto’s credentials include 38 years with the National Weather Service, from which he has retired, and he is a Bridgewater State University earth science assistant professor. While working for the weather service, he devised his own system for predicting winter snowfall, and it was published by the National Weather Association in 1978.
“Some use meteorological influences like La Nina or sunspot cycles, but I use the climatological relationship of the temperatures,’’ Pannuto said recently. If temperatures in October and November are higher than the average for each of those months, the winter will have less snow, based on his system, he says. During years when one month is cooler than average and the other warmer, Pannuto uses November as his indicator. He says his system has enjoyed a 73 percent success rate over the last three decades.
This year was easy to predict, Pannuto said. “October averaged 3.6 degrees higher than the average and November was 5.4 degrees above,’’ he said. “I think that’s statistically significant, and the probability of less snow is very strong.’’
Pannuto concedes not everyone agrees with his methods. “A lot of people think it’s apples and oranges to connect fall temperature to snow fall,’’ he said. “But I say it shows a trend.’’
Those who take stock in the Farmer’s Almanac, which has been around since the late 1700s, have their shovels at the ready, since the publication predicts two blizzards this month. The region’s heaviest snows are slated for mid-December, mid-to-late January, and mid- and late February, the Almanac’s experts say.
The Almanac bases its long-range forecasts on solar activity, weather patterns over a 30-year period, and prevailing atmospheric conditions, and this year it predicts snowfall at slightly above average.
The publication boasts a 90 percent accuracy rate - although that figure relies on predictions spread over the entire nation. Last winter, its forecast for this area turned out to be wrong. Its forecast was for heavier-than-average snow for the mid-Atlantic region but not in the Northeast, where more than 80 inches eventually fell - 40 more than the average seasonal snowfall. Since its predictions were largely on target across its other geographic regions, however, the Almanac maintained its 90 percent rate.
Meanwhile, the National Oceanic and Atmospheric Administration’s Climate Prediction Center in Washington, D.C., recently unveiled its winter outlook for the nation - but it hedged in its snow forecast for the Northeast.
The center produced a rather unhelpful report, predicting “equal chances for above-, near- or below normal temperatures and precipitation.’’
“If enough cold air and moisture is in place, areas north of the Ohio Valley and into the Northeast could see above-average snow,’’ it added.
The center’s deputy director, Mike Halpert, said La Nina, or a cooling of the tropical Pacific Ocean in effect this year, can influence weather patterns worldwide and will shape winter weather in some places, including causing colder and wetter conditions in the Pacific Northwest and drier conditions in the Pacific Southwest.
But La Nina’s influence on the weather in the Northeast is likely to be trumped by surface air pressure called “Arctic oscillation,’’ which can drive cool air southward into the United States from Canada, and turn wet weather to snow. The Arctic air pressure, Halpert said, was responsible for the cold and snowy conditions the area experienced the last two winters.
“I get a lot of calls for winter predictions from the Northeast, and those are the most difficult ones,’’ Halpert said. “I’d much rather get calls from Texas, where La Nina plays a bigger role.’’
Long-range weather forecasting has a long way to go before reaching a high degree of reliability. While computer modeling has made short-term forecasting 90 percent accurate, “seasonal forecasting is still light years away from that,’’ Halpert said.
For those who prefer to rely on folklore for their predictions, there are plenty of indicators they can use.
Wider brown bands on the wooly caterpillar indicate a mild winter, legend says. But if squirrels are gathering large stores of nuts, wasps have built nests high in the trees, and skunks sport thicker and broader white stripes in the fall, look for the snow to fly.
Christine Legere can be reached at firstname.lastname@example.org.