Any Correlation Between Hurricane Count and Fall Temperatures

[Frank Kienast]

From casual observation (not scientific by any means), it would appear that years that have a lot of Atlantic hurricanes tend to have a warm fall in the eastern US. Has anyone studied this correlation?

Intuitively, a hurricane transports a lot of heat north, so this would make temperatures warmer at mid latitudes. But I could also argue that (assuming the hurricane affects land) that it adds a lot of moisture to evaporate, which could lead evaporational cooling and more cloudiness.

Any thoughts?

Thanks,
Frank

 

[Zach Young]

I'm not really sure and I don't have time to research this at the moment, so I wouldn't be able to tell you anything for sure. My initial reaction is that even though tropical systems transport a lot of heat poleward, it's still not enough to make a perceptible impact on the temperature over a large region. Especially if you're talking about a time period of several months.

If your casual observation is correct and years that have a lot of hurricanes make for a warmer fall on the east coast, I would suspect that it has more to do with synoptic and planetary scale weather patterns. My thinking is that the large scale patterns that are favorable for Atlantic hurricanes also tend to make the east coast warmer. My first suspicion is that the Bermuda High - which provides the steering flow for many tropical systems - also causes a general southerly to southwesterly flow regime over the eastern US (warm air advection). If the Bermuda High is especially large or strong, it may also deflect mid-latitude systems and the fronts that come with them.

There may be other processes or patterns at work, but that's what immediately springs to mind 20 minutes after rolling out of bed