You Know It's Going to be a Bad Year When...(a thread for lamenting the long-term downturn in chase season quality)

[Greg McLaughlin]

Looking back at some of the most notable outbreaks across the traditional tornado alley and comparing it to more recent tornado events over the past 2 decades, something stands out to me. The most notorious past outbreaks (3.13.90, 4.26.91, 5.3.99) all featured a deep longwave trough over the inter mountain west. Both 4.26.91 and 5.3.99 which are the gold standard for intense tornado outbreaks in the plains featured a 500mb longwave trough centered over the northern Rockies with an intense jet diving on the backside of the trough and the "ski jump" jet streak ejecting into the Plains during the peak of the diurnal cycle. That is something we haven't really seen in the past 2 decades aside from 5.29.04, but on that event the flow was much weaker than the previous mentioned events. The 3.13.90 outbreak has some synoptic similarities to 4.14.12, however the tornadoes of 4.14.12 were not nearly as intense as 3.13.90.

Other outbreaks like 5.10.10 and 5.24.11 featured compact upper lows, and not the longwave troughs like the previous mentioned outbreaks. A few other notable events include 3.28.07 and 5.4-5.5.07 which featured deep closed lows.

I am curious as to why we aren't seeing the synoptic scale troughing like we have with events like 4.26.91, 5.3.99, and 5.29.04. Is this possibly a result of a changing climate or is it simply a numbers game and eventually synoptic patterns similar to these events will return? Obviously there are other regional tornado outbreaks that have occurred over the past few decades, but these that I have mentioned have been the most notable.

 

[Warren Faidley]

My own "non-scientific" opinion (although I did extensive, life-saving research during Hurricane Sally by driving through some wind while screaming), is that global climatology has shifted. There are shifts all over North America the world. Arizona had the second driest monsoon in recorded history this year. The US had the most active hurricane season on record and the west coast burned-up. On "June 20, the high temperature in Verkhoyansk, a town in northeast Russia about 260 miles south of the Arctic coast, topped out at 38 degrees Celsius, or 100.4 degrees Fahrenheit." It may also have been the hottest temperature ever recorded north of the Arctic Circle. The list goes on. The only thing that may save us now is a major volcanic eruption that creates a thin, earth covering ash cloud to cool off the planet.