I've done this job for 12+ years now. To this day, the chance of rain continues to be a point of confusion among a large majority of people.
That's not me saying the public isn't intelligent. It's quite the opposite.
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We, the weather industry, need to do a better job explaining this.
So, let's try to make sense of it all.
Probability of Precipitation
The Probability of Precipitation is the chance of rain in a given area. Believe it or not, there's an equation for this.
POP = C x A | where C is confidence and A is area.
Here's my issue with that. How do you quantify confidence?
For example, if I say that I'm 70% confident in something - what am I basing that off of? To me, it just seems like I'd be picking a random number between 1 and 10.
What do we mean, then?
At the end of the day, it's not that deep. Let's simplify things.
We're almost always referring to the percentage of the area that will see rain. We cover 23 counties, not just one town or one city or one neighborhood.
Picture our area as a pizza pie, and the pepperoni slices are showers and storms.
• If 10% to 30% of the area sees storms, they're isolated.
• If 40% to 60% of the area sees storms, they're scattered.
• If 60% to 80% of the area sees storms, they're numerous.
• If 80% to 100% of the area sees storms, they're widespread.
It's why I, personally, have been trying to steer clear of saying "chance" of rain and instead say "coverage" of rain.
When able, we try to specify which areas will see rain. However, sometimes that's impossible.
When dealing with scattered storms, it's sometimes like trying to predict which kernels in a bag of popcorn will or will not pop.
What do the percentages mean in the near-term forecast?
In the summer months, you are most often going to be dealing with isolated-to-scattered coverage of storms.
That's been the case in recent days, leading to streaky high rain totals and places left high and dry.
I would expect more of the same Friday through Sunday. Each afternoon and evening, the heat and humidity build and lead to almost randomly-placed showers and storms.
Some get poured on. Some see nothing but sun and cumulus clouds.
Welcome to summer in North Carolina, friends!
This drought has been frustrating, but it's going to take months before we're completely done with it at this rate.