Thread by @WeatherProf

New: 2 rapid attribution studies on the impact of climate change on Hurricane #Helene have just been released. The results are very significant, yet unsurprising.
Warmer air, warmer water = much heavier rainfall rates. First study: ~50% increase in rain in parts of NC/ GA!! 🧵

First from @MichaelFWehner, who is one of the World’s experts on the connection between climate warming and Tropical cyclones.
“…our best
estimate is that climate change caused over 50% more rainfall during Hurricane Helene in some
parts of Georgia and the Carolinas.” 2/

@MichaelFWehner “Furthermore, we estimate that the observed rainfall was
made up to 20 times more likely in these areas because of global warming.”
That’s study number 1. Now let’s discuss study number two…
3/

@MichaelFWehner Analysis from Climameter: “Climate change made the heavy rainfall from Hurricane Helene up to 20% more intense and the strong winds up to 7% stronger than they were at the end of the century, according to a new analysis by a group of researchers from Climameter.” 4/

@MichaelFWehner Here’s the link to the Climameter study:
Now some commentary from me in the next tweet… 5/climameter.org/20240926-27-hu…

@MichaelFWehner Me: #Helene was a very unique event. The main driving force of the flooding in NC was tropical moisture being forced into mountainous terrain! First a “predecessor event” saturating the ground and then a fast moving hurricane slamming into the mountains, spiking rain rates 6/

So this disastrous flooding would have occurred regardless of climate change, just from natural factors alone.
However, the record hot Gulf and baseline warmer atmosphere enhances the heaviest tropical rain rates by much greater than the Clausius–Clapeyron relation. 7/

C-C says 8% more moisture per 2F increase in temperature.
For a more comprehensive explanation ask/ follow @MichaelFWehner

@MichaelFWehner Here’s Michael Wehner’s analysis:
drive.google.com/file/d/14oq65l…