Here’s a bit of a geek out moment… We tracked Saturday’s nor’easter along with you for days. During that time talked a lot about an Upper Level Low pressure that was going to dig into the southeast, before becoming a nor’easter Saturday night.
An Upper Level Low (or ULL) occurs at the jet stream level, and among other characteristics, it causes the air associated with it to rise. As the column of air rises, it cools. If an ULL is strong enough, that cooling air can fall all the way to the earth’s surface (it’s like in the movie ‘ The Day After Tomorrow’, only the air is around 32°… not -132°).
Well, Saturday morning the very strong ULL was over top of western South Carolina. The column of air below the ULL cooled dramatically, and the result was snow. You see, temperatures in South Carolina were in the low to mid 40s for the most part… by no means a nice day… but far from cold enough for snow. Under the center of the ULL, temps fell into the low and mid 30s. So in a location, it could be raining in the low 40s ahead of the ULL… then quickly drop into the mid 30s under the ULL and change to a heavy wet snow… and once the ULL passed to south and east, temps warmed back to around 40°, and the snow changed back to rain.
Case in point… Lexington, South Carolina (located just west of Columbia on the radar below):
This radar image is kinda cool… in that you can clearly see where the ULL is located at this moment in time. A small circle of snow, with rain falling in all directions around it… even the higher elevations. It was raining in Lexington during the pre-dawn hours, then as the ULL passed over top of the area, the rapidly rising air did it’s dirty work, and the temps plummeted. Temperatures in Lexington were around 45° at 5am… 40° a 6am… 37° by 7am… and 33° at 8am. By 8:15am Saturday morning, this was what it looked like outside your window in Lexington, SC… (hat tip to Accuweather.com)
If you’re thinking this was due to high elevation… Lexington, SC has an elevation of 394 feet. For comparison… Kingston, NY has an elevation of 476 feet. So now you see the power of an Upper Level Low (ULL). This ULL brought accumulating snow to the low lying areas of South Carolina on November 1st. So if you’ve been following HVW over the past week, and wondered why we were so animated about Saturday’s nor’easter, it’s because it was a powerful event. So powerful, that it brought snow to places that have never seen snow this early in the season. Mother nature is amazing! Thanks for all the support you’ve shown HVW, and we hope you enjoyed this little ‘nerd session’… class dismissed.