(WKBN) – We are rolling into another fall and winter with La Nina climate pattern in play.
La Nina is known as the cool phase of the (ENSO) El Nino Southern Oscillation climate pattern. This all takes place in the tropical pacific region off the west coast of South America and across the Pacific Ocean.
According to NOAA (Climate.gov), it is likely that we will roll into a third consecutive La Nina. In fact, it has put a 91% chance of it taking place through November and an 80% chance through January.
What does La Nina mean?
According to the Meriam Webster Dictionary, La Nina is an irregularly recurring upwelling of unusually cold water to the ocean surface along the western coast of South America that often occurs following an El Nino and that disrupts typical regional and global weather patterns, especially in a manner opposite to that of El Nino.
In the Spanish language, “La Nina” means little girl.
The pattern signifies that cold water is being upwelled off the west coast of South America. This typically takes place after an El Nino (opposite of La Nina).
This colder water will help shift weather patterns around the globe. The same goes for El Nino when there is warmer water off the west coast of South America.
Below you will see a graphic showing how the flow works in a La Nina weather pattern. The colder water flows west in the wind and can create sinking air into the central Pacific Ocean and then more rising air into the Indonesian region. During El Nino, this pattern is reversed.
The oscillation from El Nino to La Nina goes back and forth with time. There is also a neutral phase to the oscillation.
Going into the fall of 2022, we are in the La Nina phase of the oscillation. In fact, it will be the third consecutive La Nina winter.
What does La Nina mean for Ohio and Pennsylvania winter forecast?
The El Nino to La Nina Oscillation (ENSO) helps enhance/change weather patterns around the globe. This includes North America and our part of it in Ohio and Pennsylvania.
It is not an exact fact that this pattern will take shape this winter as there are many variables and teleconnections (weather patterns that are connected over many miles) across the globe that also influence our weather. These patterns will shift around and change the weather as the jet streams shift and push cold, or hot, air masses into the region. They also will determine if big storms or lake effect snow patterns will take place.
This is not a winter forecast for Ohio and Pennsylvania, but it is a guide to show you what a typical La Nina pattern can do and how that could influence our winter weather.
Keep in mind that we live in a unique part of the United States on the south shores of the Great Lakes. Lake Effect snow drives a big part of our snowfall through the winter. In order to get a lot of it, we need cold temperatures to flow from the north and northwest across the Great Lakes.
Below you will see an image of a typical El Nino and La Nina pattern during winter for North America from NOAA (Climate.gov)
Below is a group of maps during La Nina winters from NOAA (Climate.gov).
Notice that there is a lot of back and forth in our region. Some winters have been cold, and some have been warm.
The same can be said for the precipitation as they have gone back and forth for our region.
The past two winters have been La Nina winters.
Here in Youngstown, Ohio, both winters featured above-normal temperatures as an average.
There was a split on precipitation as 2020/2021 winter was below normal in rainfall and above normal in snowfall, and 2021/2022 was above normal in rainfall and below normal in snowfall.
It is typical that more rain equals less snow locally as it is typically warmer.
Meteorological Winter 2020-2021 in Youngstown, Ohio
Average Temperature = 29.8° (1.7° Above Normal)
Average Precipitation = 7.69″ (-0.57″ Below Normal)
Average Snowfall = 51.1″ (6.7″ Above Normal)
Meteorological Winter 2021-2022 in Youngstown, Ohio
Average Temperature = 30.3° (1.0° Above Normal)
Average Precipitation = 10.52″ (1.80″ Above Normal)
Average Snowfall = 41.0″ (-8.5″ Below Normal)
So, you can see that not every La Nina winter is the same here in Ohio and Pennsylvania.
In the end, a La Nina winter will typically create a pattern that will feature colder weather across the Northern Plains that can be tapped by storm systems that form in the Lower Ohio River Valley. These storms tend to swing our temperatures back and forth with each system. Warm with rain/slush on the front side and then turning drastically colder as the storm sweeps through for a short period. The colder portion can lead to more Lake Effect snow. The next storm is usually not far behind the one in front and the process starts over again as we warm back up, and then turn cold again.
In the end, we typically end a La Nina Winter wetter and slightly warmer than normal. Our snowfall is heavily weighted on Lake Effect and the occasional East Coast storm or Nor’Easter.
Fun weather fact: We typically see our worst cold/snowy winters in this region (Youngstown, Ohio) during slightly above, or slightly below, the neutral event of the ENSO(El Nino Southern Oscillation).
The fact that a La Nina winter is on the way can be used as a guide to what could happen in this type of climate pattern on any given year. It is not an actual forecast.