— WeatherNation (@WeatherNation) September 12, 2016
Get ready to ride the roller coaster. Snow is already falling at Old Faithful in Yellowstone National Park. September is a transition month between the warmth of summer, and a cooler fall-like feeling. Parading cold fronts help achieve these ups and downs.
Out ahead of the cold front, southerly winds and sunshine help drive temperatures up. The front comes through, often bringing a chance at showers and thunderstorms. Once the front passes, cooler and drier air settles, dropping temperatures by as much as 30 degrees. The Canadian high pressure brings what is known as a Continental Polar airmass. Continental indicating dry and polar meaning cool.
For example, the latest cold front to slide through the central US follows this pattern:
The High Plains saw morning lows drop by 10-20 degrees between Monday and Tuesday. Afternoon highs will only reach the 40s and 50s in multiple states. East of the front, temperatures will warm into the 80s and 90s with dew points in the 60s and 70s. As the cold, dry airmass crashes into the warm, moist atmosphere, it causes the air to rise. Thunderstorms will develop along the front, but will not likely bring severe weather.
The forecast has the cooler air spreading east and southeast the next few days. Into Wednesday morning, lows along the Canadian border could drop back below the freezing mark. Frost advisories are in place for the early hours. Don’t forget to protect plants and pets when temperatures drop!
For WeatherNation, Meteorologist Karissa Klos.