Joe’s Weather Blog: Revisiting the overuse of severe thunderstorm warnings (WED-2/15)
Good afternoon…for those of you at the seminar that I’m presenting this information too…this blog will show some of the slides that I’m using/used in my presentation. For the rest of you reading this today or Thursday…I’ve been working on this project for the past 18 months or so…and this is a follow-up blog to what I wrote about last March. That blog is available here. This blog updates and adds on some information that I didn’t get too with the last write up.
First though, if you’re attending the IWT workshop…I have a few poll questions for you.
As I’ve talked about…my feeling is that the public…my customers…don’t pay attention to the vast majority of severe thunderstorm warnings. This is NOT a criticism of the issuing of the warnings from the NWS…they have a mandate to follow…but this is more of an issue with the criteria and the end results of what typically happens after the storms move through.
This project is an outgrowth of our conversations within IWT when I brought up this subject in late 2015(?)
As we get started I wanted to tally up just how many warnings have been issued since the new hail criteria (from 3/4>1″) was introduced. Granted the NWS in MO/KS were using the 1″ hail criteria (from 3/4″) for a couple of years prior…but I tallied up when Central Region adopted the standard…which was in 2009
I also wanted to see how many were issued at other offices…in southern and western regions as well…I just picked a sampling of weatehr active CWAs. They adopted the 1″ hail criteria 1 year later than Central Region
I call your attention to the Norman office.
Notice, in the Norman breakdown above, that about 400 warnings were issued based on the minimum criteria alone out of some 900 last year. That’s almost 3/day issued and almost 1/day based on the minimum criteria. Granted their coverage is all of central and western OK, a lot of territory…but I have a tough time thinking folks are paying attention to MANY of the 900 warnings in 2016
I wrote a blog last March with these initial findings…I wanted to know what my viewers/readers thought of the current SVRs in their current state. It should be noted that the majority of my blog readers are a bit more weather “savvy” than a typical viewer might be I think. I asked these questions at the beginning of the blog.
Obviously I’m interested in the “deeper dive” of the 2nd question. Hence what follows.
I went into the last 5 years of SVRs issued by the NWS in Pleasant Hill. I checked all the (Impact Based Warning tag information) for the initial reason why the warning was issued.
In particular I wanted to see the quantity of 60 MPH wind warnings and/or 1″ hail triggers. Those are represented by the orange bars above…the red bars are the total warnings issued. The percentage values are the 60 MPH and/or 1″ triggers. So in 2016 roughly 55% of ALL warnings issued were for the minimum criteria to issue a warning.
I was then curious about the verification of these minimum warning issuances. In most cases…well under 50%. They are tough to verify many times…especially IF they happen in the middle of the night. Also with so many rural counties out there…(if a tree falls in the forest does it make a sound?).
So what would happen IF we changed the minimum criteria…how many of these warnings would drop off IF we went to 70 MPH winds and/or 1.5″ hail minimums. The warnings issued are represented by the orange bars. Also note that as I mentioned in my presentation at IWT…the actual number of initial warnings issued based on the minimum criteria that then intensified into a 70 MPH and/or 1.5″ hail tag were pretty small…mostly under 10 per year or so.
We’re talking about 20-25% of the warnings would be issued….in other words, even being a bit generous…60-70% of the warnings would be reduced…that’s pretty significant!
My thought is IF we don’t issue so many…when one is issued would our viewers and your customers pay more attention to what’s happening. Are they fatigued by the sheer volume of warnings.
After I wrote that March 2016 blog…I asked some additional poll questions and was encouraged by the middle answers especially.
This though isn’t a perfect process…there are other issues to this research.
So here is the final poll question…
As always you’re free to leave a comment here or email me at joe.lauria at wdaftv4.com . Am I crazy?
Thanks for your time and attention.