When Jay Berschback called up a screen on one of his computers showing the forecasts from three prominent weather-prediction models Wednesday afternoon, all three showed a storm forming over north Texas on Thursday and tracking northeastward toward northern Ohio.
One of the three, known as the “Canadian model” because of where it was developed, showed the storm tracking far enough north to draw in above-freezing air aloft, causing a bit of freezing rain or sleet to mix in Saturday night with the snow that would otherwise dominate.
BREAKING NEWS: Toledo breaks Feb. 20 temperature record
The other two — the Global Forecast System model developed by the National Weather Service, and the “European” model developed by the European Center for Medium-Range Weather Forecasting — called for a slightly more southerly track, but far enough into Ohio that Toledo seemed targeted for a significant snowfall late Saturday.
But by Thursday afternoon — with the storm’s expected arrival now less than 48 hours away — most models called for its center to stay even farther south as it passed Ohio. That prompted Mr. Berschback to predict Thursday evening that Toledo will get 1 to 3 inches and a little sooner than indicated, he said.
“The main batch of snow will be during the day and evening Saturday,” the forecaster said.
In generations past, a storm like this one might not have gotten on forecasters’ radars until it literally appeared on the instruments. But ever-growing computer data-crunching capacity has given meteorologists the ability to use current weather data, including air temperatures, moisture content, and wind velocities — from the surface up to tens of thousands of feet aloft — to predict the storms’ development.
Brett Anderson, a senior meteorologist with AccuWeather Inc., a private forecasting service based in State College, Pa., said that when he entered the field a quarter century ago, “three or four” mathematical forecasting models were used. Today, there are more than 30.
“There are a lot of models out there, and it can get confusing,” Mr. Anderson said. “The different models produce different forecasts. Models have improved ... the resolution is much better.”
Model-based meteorology attracted political scrutiny late last month when an East Coast blizzard many forecasters said would slam New York with 2 feet of snow instead produced less than a foot.
But Mr. Anderson noted that the storm’s forecast track wasn’t that far off — communities just east of New York got all of 2 feet and more, and predictions for metro Boston to get slammed were spot-on.
All of the models start with the same data, gathered from weather reporting stations, aircraft, buoys and ships at sea, and weather balloons launched high into the atmosphere, plus radar readings and satellite cloud imagery.
What differs is the complex formulas each model uses to crunch those numbers.
Mr. Berschback said the latest trend is for individual models to be run in “ensembles” — say, 60 times with the same data, but minor adjustments in forecasting variables — to produce a range of potential outcomes with softer edges, rather than a solitary forecast track for an air mass or a storm.
“My job is to look at the different forecasts from the models, and pick and choose the data that seems most credible to me,” the WTVG meteorologist said.
Mr. Berschback said the models he consults have different time ranges. Some are designed for short-term forecasting of 15 hours or less, but are precise — especially valuable for predicting severe-weather outbreaks in the summertime. At the other end are models that go out to 15 days and are more appropriate for predicting trends than storm tracks.
After another morning of subzero — and likely record-breaking — cold to start, Mr. Berschback and the National Weather Service said Thursday afternoon that Toledo’s temperatures would warm gradually but steadily today and Saturday, including through the night in between.
Northwest Ohio and southeast Michigan first will get about an inch overnight from a weak weather system passing to the north, the forecasters said, then the more significant accumulation Saturday from the storm to its south.
If Thursday’s forecasts for the weekend hold up, Toledo will come close to breaking its record for the snowiest February. Through Wednesday, 22.4 inches had fallen this month at Toledo Express Airport, 2.8 inches below the record for the month set four years ago.
This month’s total snowfall was already 0.6 inch more than fell last February, but with December having tied for the least snowfall in Toledo history at just a trace, and January being just a bit above normal, the season total so far was just 37.4 inches. That’s 9.8 inches above normal but still far below last winter’s record-setting pace.
Toledo is on track, meanwhile, to have one of its coldest Februaries ever — even colder than the 17.7-degree average daily mean that put February, 2014, in eighth place on the local Top 10 coldest list. The lowest temperature registered Thursday at The Blade building was -1 at 8 a.m.
Forecasting models consistently showed well in advance that this February’s second half would be much colder than normal in the Great Lakes region, Mr. Berschback said.
“To know that the end of this month was going to be very cold, from something that’s so variable and so chaotic, is pretty amazing,” he said.
Contact David Patch at: dpatch@theblade.com or 419-724-6094.
First Published February 20, 2015, 5:00 a.m.
