SPC Hazard Yellow Slight and Severe Question

[Bobby Little]

This question has been a sore spot for a while now. I have have lightly searched SPC and here, but not found my answer...maybe simple?
So on SPC main home page just under SPC activity chart/map, the Hazaed table lists each day for 1 week. Slight risks are yellow but sometimes Severe yellow. The map Severe risk legend 4-8 is yellow 15% or Enhanced 30% orange.
When looking at the SPC level chart it shows light green, 1 MGL (dark green), 2 SGT (yellow), 3 ENH (orange), 4 MDT (red), 5 HIGH (magenta).
My question is: Should the chart show SLGT as 2.1 or 2A and Severe 2.2 or 2B? or SLGT as 2, Severe 3, ENH 4, ...so on?
I have always taken a SLGT risk as that and a Severe risk as stonger than SLGHT.
This might be an easy answer, but it has perplexed me forever. Help!

 

[Mike Smith]

Hi Bobby,

Many people will not like my answer but here goes:

You aren't the only person to notice inconsistency. The SPC colors are a mess.

We tell people lightning is a hazard. Green, which people associate with safety, should not be used to depict thunderstorms, let alone marginal risks of tornadoes and severe thunderstorms. Second, multiple studies show people associated red with the highest risk of danger, not purple.

More importantly, there appears to be little to no improvement in tornado forecast accuracy the past decade, in spite of -- or perhaps because of -- the development of CAMs.

My personal opinion is that five categories is too many. I don't believe we have the skill to slice the bread that thin.

Here is what I would change:

• General thunderstorms would be a warm gray color.
• Significant risk would be yellow.
• Enhanced risk would be orange.
• High risk would be a warm purple.
• Extreme risk would be red.

They have been looking at the outlooks for years. The NWS has a serous cultural problem where decisions to take make changes take years or even decades. Unfortunately, I don't expect changes anytime soon.

 

[Bobby Little]

All good points Mike, especially with assumed colors like green and red. I just dont like the slight and severe yellow and % deplictions. It seems to make thing more complicated. Change would be nice but then you have to think about the former colors as being learned and ingrained and how fast people would adapt. I am sure many would complain of a new change. But probably one that should be well thought out and implemented.