(WHTM) – Last winter was another disappointment for snow lovers in central Pennsylvania. For the entire season, we picked up around 15″ of snow. Two of our last three winters really lacked snow, with the winter of 2019/2020 being our least snowy on record. Is there any hope for ski or snow lovers this winter? History says yes.
We’re heading into yet another La Nina winter, which would make it the third straight or a ‘triple dip’. This has only happened twice in the last 75 years, and when it has…it has led to a colder than average December.
The sample size is small though, so we can’t base our outlook on this completely.
El Nino and La Nina are phenomena that occur over the equatorial Pacific Ocean. Trade winds in this region of the Pacific Ocean blow east to west, and during a La Nina period the winds are strong. This stronger flow of wind from east to west also impacts the surface waters of the ocean.
The wind helps to push the water from east to west, and stronger winds therefore push the water more and more westward. This process draws up colder water from greater depths on the eastern side of the Pacific Ocean basin. The colder water then reaches the surface and impacts the weather in the area. In turn, this cold pool of water and air nearby then influences downstream weather patterns into Central and North America.
Typically in a La Nina, cold air is centered over the northern US and western Canada, with a southeast ridge keeping warm air nearby. But in an east-based La Nina (what we’re in now), water temperatures are coldest east near South America, which tends to pull that colder air a bit east. Last year is a great example.
We were quite chilly during January and parts of February. In those months, the temperature fell below 20 degrees 18 times, the highest since 2018. There are similar signs ahead this winter, with a strong signal in long-range models of ridging between Greenland and Scandinavia in early December. This also tends to ‘push’ colder air south into the United States.
It is clear we will have our rounds of chill this winter. But like last year, cold doesn’t always guarantee snow. An active Pacific jet will give us opportunity for snow, but we’re more likely to have a number of mixed-bag events. We’ll go through our ups and downs in January and February, but it may take a little while for warm weather to stick around come March.
In summary, here is what we can expect this winter:
- We can expect some early season cold spells (a few days at a time)
- An overall more seasonable December
- A colder January
- Milder February
- Precipitation chances will lean in favor of mixed precipitation
- Lower chance overall for nor’easters or big snow storms
- **Total season snow will be closer to average (30-40 inches)**