Blog Article

Why the Weather Intensity Score Just Got More Honest

What was inflating the Weather Intensity Score, what we changed, and how to read the new numbers.

If you watch our streams, you know the Weather Intensity Score. It is our one number for how intense the weather is across the country right now. It drives a lot of what we do, from when we go live to how hard our systems push behind the scenes.

Lately it had been running inflated. It was reading in the 90s and even breaking 100 on days that were busy, but not dangerous. On Friday it hit 151 while the actual weather was a whole lot of garden variety storms. That is not what a number like that should mean. So we dug into the math, found exactly what was inflating it, and fixed it.

Quantity was getting confused with intensity

A day with 700 run of the mill storms could outscore a day with a handful of violent ones. Radar was seeing storms everywhere, and every single one of them kept adding a little to the score with no limit. None of them were strong. It did not matter. The pile got huge anyway.

Now, weak storms stop adding up past a point, while strong storms always count in full. And this part matters to me a lot: storm cells show up on radar before warnings get issued, and the score rising early, ahead of the warnings, is one of the most useful things it does. We protected that. When dangerous storms are organizing, the score still climbs before the first warning drops.

Big cities counted a little too much

A tornado warning over a major metro absolutely should score higher than the same warning over empty fields. More people in harm's way is a bigger deal. That is still true, and it is still in the score. But the city boost had grown large enough that ordinary storms sitting over a metro area could push the score into territory that should be reserved for genuinely dangerous weather. We kept the boost and trimmed its ceiling.

Coverage is not weather

Some supporting signals, like how many storm cameras we have live, feed into the score. They are useful context, but they measure our coverage of the weather, not the weather itself. Those signals now count for about half of what they used to.

What this means for you

The score will read lower than you are used to, especially on busy but not dangerous days. A calm day reads the same as it always did. The difference is at the top of the scale: when you see this thing at 90 or above now, it is because violent weather is actually happening, not because a lot of little things piled up at once.

And if you were watching Friday afternoon and saw the score fall off a cliff in one step, that was us flipping the switch to the new math, not the weather suddenly calming down.

Same score, same place on the site and the streams. It just tells the truth a little better now.

https://ryanhallyall.com/blog/weather-intensity-score-recalibration