Rain chances confusion: What does probability of precipitation mean?

NOW: Rain chances confusion: What does probability of precipitation mean?


Picture this: You open up the ABC57 First Warning Neighborhood Mobile Weather App and see that a particular day has a 30% chance of rain or snow.

That's all well and good, but do you know what that number actually means?

If you're confused, you're not alone. A viral TikTok reignited the debate this week, and caused many to scratch their heads.

A twitter poll that ABC57 put out Tuesday points to some doubt regarding the meaning behind the percentage we look at every day.

Additionally, many meteorologists disagree when it comes to probability of precipitation, or PoP. A recent study finds that a large portion of meteorologists think that PoP has a very limited value. The broadcasters surveyed say that about 75% lacks accurate understanding of PoP, and less than 10% felt that the definition of the percentage was applied consistently.  

With that being said, probability of precipitation tries to depict whether or not you need to prepare for rain or snow. 

Some argue that it's a combination of forecaster confidence and how much of the area will get rain or snow, which is what the viral TikTok video is suggesting.

Others say it's just how much of a forecast area will get rained on.

Here at ABC57, we define probability of precipitation as the likelihood that a specific point will get rain or snow within a period of time. That point is usually South Bend.

Part of the problem with PoP is for all that it tells you, there's a lot more that is doesn't tell you.

The percentage doesn't let you know how hard it will rain, it doesn't let you know how much rain you'll get, and it doesn't let you know how long it will rain for.

When you're checking out the ABC57 mobile weather app, you can use PoP as our confidence in the possibility of rain where you are.

Sometimes, it's not that simple. What if you are traveling, or lake-effect snow is only going to affect Berrien County and not the rest of Michiana? We use terms like isolated, widely scattered, scattered and widespread and ThreatTracker to help let you know where in Michiana it will rain and snow and who will be impacted the most.

And, if you still have questions, watch the forecast! We'll be sure to break down exactly what you need to know.

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