What does an active tropical season mean for snow in the Tri-Cities?
I know what you're thinking, "Winter?! It's not even September yet!" Trust me. I don't know why my mind wanders to the places it does, but here we are.
Harvey's destruction is on almost everyone's mind nationwide, but there's one thing that hasn't been mentioned much. Since 1950, this is the 10th year in which the eighth named storm has come before September 1st.
Why does that matter? Well that might play a role in the upcoming winter. Tropical systems unleash a lot of heat towards the poles. In the winter, the atmosphere may need to make up for whatever heat isn't transported during the tropical season. (This is something I was taught by Dr. Gary Lackmann at NC State in my senior year, and it still amazes me.)
So, here's what I did. I found the other nine years that had eight named storms before September 1 and saw what happened the following winter. For you statistics gurus, we're working with a small sample size here. That puts us at a disadvantage, but still is worth the research to me.
In the nine years that saw eight named storms prior to 9/1, seven of the following winters featured below average snowfall. (And I mean way below average.)
One possible reason for that is that there was a lot of heat transported to the poles in the tropical season, and so the atmosphere didn't have to make up for the lack of balance in the winter. That would mean less snowstorms and thus, less snow in the Tri-Cities.
Let's try this another way. Let's just say that since we've had eight named storms halfway through the tropical season, that we're 'on pace' for 16-18 named storms for the entire season.
There were also nine seasons since 1950 in which that happened, and seven of the nine featured below average snowfall.
As was brought up to me by two fellow meteorologists from North Carolina, there's another way to look at this. I could look at the 'Accumulated Cyclone Energy' per year and look at the snow that followed.
Accumulated Cyclone Energy (ACE) "is used to express the activity and destructive potential of individual tropical cyclones and entire tropical cyclone seasons," according to Weather Underground. Since 1970, the average ACE in the Atlantic is 110 x 10 4 .
Seven of the nine seasons that had an 'H' storm before 9/1 had above average ACE. Out of the 16 years that had above average ACE since 1970, though, 14 of the following winters had below average snowfall.
If we find that this year's ACE is above the average of 110 x 10 4 then we can possibly use that as part of our winter forecast down the road. There are obviously many other factors that we have to consider, but this may have to be one of them!
Hope you enjoyed reading this post! If you ever have feedback or things that you want us to explore further, feel free to let us know!