Thursday’s storm brought more snow than many expected. Here’s why
As of 6 p.m. Thursday, AccuWeather and National Weather Service spotters were collecting reports of 6-10 inches of snow in the State College area — with more possible.
After Wednesday projections of 2-4 and 4-6 inches, the snow accumulation exceeded expectations, and brought a rare heavy November storm.
“Snow came in this morning and it snowed like crazy from late morning through the afternoon, I mean, it was snowing hard,” AccuWeather senior meteorologist Bob Smerbeck said. “One guy here at work reported 1 inch of snow in 15 minutes, so that tells you, if you add that up, that’s at a rate of almost 4 inches per hour. So that was extremely heavy snow.”
Of course the snow did not keep up that pace throughout the rest of the day, but as the snow had just started to turn to sleet and freezing rain around the 4:30-5 p.m., it had lasted longer than originally expected.
The reason for that, Smerbeck said, was that two clashing systems brought in more cold air than anticipated, keeping conditions colder for snow to last longer.
“We have a very potent storm center coming up the East Coast right now and tons of moisture from the Gulf of Mexico headed northward and intersecting a cold Canadian air mass, an air mass that’s colder than average for this time of year,” Smerbeck said. “So there was a big clash going on, and when you get big differences and clashing air masses like that, something big happens — and we had a big winter storm today.”
Although not all the data had been collected and not all the research conducted, Smerbeck said Thursday’s snow total was almost certainly a record for Nov. 14, and one of only a few blockbuster snowstorms to have happened in November in central Pennsylvania.
Although snow had gotten up to 8.5 inches in Park Forest, 8 in Stormstown and 7.5 in Bellefonte by 6:30 p.m., according to NWS spotters, Smerbeck said the rain and sleet Thursday evening would eat away a bit at the snow totals. However, the wintry mix was expected to turn back into snow overnight and add another inch or two.
“Since this storm is coming up out of the Gulf, it’s got a lot of warm and juicy air with it, so it’s running over top of that cold air, and now the snow has finally met its match and we’re going to get into some sleet where the air is warm and moist overhead but the air by the surface is still cold, is still freezing, so the raindrops are freezing into pellets.”
When it was all said and done, Smerbeck said he expected there to be 8-12 inches of snow — quite a bit more than the original 2-4.
The cold air mass from Canada brought colder-than-expected temperatures, with readings at the University Park Airport hovering around 27 degrees for most of the day, making conditions ripe for snow accumulation.
“So that and boy, the intensity of this storm. I mean you got so much warm and moist air from the Gulf going up over that cold Canadian air mass — and that was cold — all across the northeast and Ohio Valley. it’s unusually cold for this time of year,” Smerbeck said. “These are temperatures we’re more likely to see in January than November, so it was kind of a set up of two powerhouses, a very moist system coming from the Gulf into a very cold air mass from Canada — and that doesn’t happen that often, to say the least.”
By 10 or 11 p.m. Thursday, Smerbeck said the freezing rain and sleet was expected to turn back into snow, and continue until about 4 or 5 a.m. Friday. After that, a few flurries might hang around into daybreak, but overall, the storm should be through Centre County by morning.
However, that doesn’t mean that the hazards will be out of the way. With the cold ground temperatures, Smerbeck said it could take awhile for the snow to melt.
“Residual snow and a lot of debris snow around will make for slippery travel,” he said. “The precipitation will have ended, but it’s still going to be pretty slippery in the morning. Things ought to improve by mid-morning, definitely by lunchtime.”