Do You Feel “Slighted” By Severe Weather Outlooks?
Note: I want to thank everyone who gave their thoughts on my questions about weather forecasting over the weekend. Your response will give great fuel for the discussion on tonight’s WeatherBrains. Here are links to the other two posts:
Sacred Cows Make the Best Burgers
Your Thoughts Please
TODAY’S DISCUSSION…
What do you think of when you think of the word “slight”? Do you think “small”? Do you think “of little importance”? Do you think “not serious”?
That may be what you think when you hear a convective outlook from the Storm Prediction Center. Severe thunderstorm risk areas are defined as slight, moderate and high. That nomenclature has been used since 1980.
Prior to 1980, the terms “isolated,” “few,” “scattered” and “numerous” were used. When the change was made in 1980, the terms used were “low,” “moderate” and “high.” It was decided that in theory, the risk is never “zero,” it is always at least “low.” Hence the change was made that fall to make the lowest category “slight.”
In 1980, the general public was not listening to the convective outlooks. The only people who read them were National Weather Service employees, pilots and people who visited National Weather Service offices.
Today, things are different. The daily severe weather outlooks are read by hundreds of thousands of people on the internet and are a mainstay of television weather broadcasts all over the company. Perhaps it is time that the terminology be rethought.
The slight risk category corresponds to a 5-15% probability of severe weather within 25 miles of points in the outlook area. The moderate risk category corresponds to a 15-30% probability and the high to a greater than 30% probability. Monday night’s Guest WeatherBrain, Dave Freeman, says that 30% is only good in baseball.
If you could change the risk category names, what would you change them to?
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February 8th, 2010 at 10:19 am
Ultimately, the convective outlooks from the Storm Prediction Center are still **forecast guidance** for people who understand them. Even though they are available on the internet, it’s reasonably safe to assume that anyone who knows what the SPC is and what the link to their webpage is… understands the products enough to know that “Slight” isn’t what it would sound like to the average person. The real problem is that they are being shown to the average public on TV and such… as is. This is where there is a breakdown of understanding the terms. While the watches from the SPC are products designed to more directly alert the public of hazards, the outlooks are guidance products to help forecasters and emergency managers assess the threat. It should ultimately be up to the broadcasters presenting the information to make it clear for the general public to understand. That’s what they get paid to do. Several stations in Tornado Alley, including KWTV in OKC already use things like “Risk” and “Enhanced Risk” for SPC’s SLGT and MDT areas when presenting things on television and radio. It’s not that hard to make a few graphical changes in the ole WSI, WXC, AccuWx Galileo, or Baron systems. It’s the job of the broadcaster to make the information understandable to his or her audience. Do we ask the NWS to change or tone down their AFDs for the general public to understand, even though they are shown online for everyone to see, if they know where to go? A convective outlook is **only** a national level AFD that pertains specifically to severe weather. We also don’t ask the NHC to simplify their discussions… or the HPC… other other NOAA agencies.
Not pointing any fingers, just my $0.02…
February 8th, 2010 at 10:26 am
I would keep the Moderate & High risk category..And would change the “slight” risk to an “Enhanced” risk..It would grab folks attention better without freaking them out..JMO
February 8th, 2010 at 10:28 am
Here is how I interpret those terms:
Slight=pay no attention
Moderate=turn on the TV
High=take iPhone into the basement
You guys do an awesome job!
February 8th, 2010 at 11:13 am
I hate the “slight” wording just as much as I hate TV mets saying things like “weak, spin-up tornado” (ask the person who’s car has just been blown off the road into a deep ditch resulting in life-ending injuries just how “weak” that tornado was). By wording it like that people are going to think “no big deal”. The way to deal with this, at least as far as the convective outlooks are concerned, is absurdly simple.
Level 1 – “Risk of severe weather”
Level 2 – “Moderate risk of severe weather”
Level 3 – “High risk of severe weather”
Just take “slight” out of the first, and you’re done
February 8th, 2010 at 11:15 am
Stick with “Moderate” risk.
Change “High” to “Significant”. Should go hand-in-hand with PDS notices.
Personally I would convert “Slight” back to “Low” risk. Low just states the risk better. Or, maybe just come out with it and say “5-15%”. Wait, no don’t do that…then there would be confusion similar to “Partly cloudy with 10% chance of rain”. Scratch that.
February 8th, 2010 at 8:03 pm
Catherine, James, Tim, JB, Brian, and fellow bloggers;
Here’s how I use the terms.
Slight = there IS the miniscule chance for severe weather, but not likely.
Moderate = keep aware of what’s happening, but go on about your business.
High = Go about your business but expect some type of severe weather; keep informed on the weather situation by the news media; be ready to react.