The percent chance of precipitation

[ColdFront77]

The percent chance of precipitation does not literally mean the "percent chance of precipitation."

For example, say the National Weather Service has a 60% chance of afternoon showers and thunderstorms for your county (or parish)..... this does not mean that there is a 60% chance of precipitation for your immediate are and there is 40% chance that there will be no precipitation.

It means that 60% of the area being forecast by your local National Weather Service office will see rain during the period being forecast.

[wx247]

Thank you for clearing that up. I have actually seen two tv mets. fight over this very topic when I interned at the CBS affiliate in high school. I just sat back and watched it happen. And the funny part is... I asked the question.

[ColdFront77]

Here it is Garrett and Jeremy.

[breeze]

Tom, thanks so much for posting that! I'll admit that, like most
other folks, I thought it meant literally a 60% chance of
rain occurence! That's a great weather tidbit - thanks!

[ColdFront77]

You're welcome Annette. No problem. It is easy to understand that many people don't understand this concept in the National Weather Service forecasts.

[Stormsfury]

And when you get rained upon, you are 100% WET!...*LOL*

Sorry, couldn't resist!...*LOL*

Seriously, good post, Tom.

[breeze]

Lmao, Mike, I didn't have to be brilliant, weather-wise,
to know THAT one!

[wx247]

I am still confused... so that means that if there is a 60% chance of rain that 60% of that "zone" will get rain?

[Aslkahuna]

(which is a change from past years) then they need to change the wording on their forecasts as well as the labelling on the MOS from the models since the POPs there are clearly point forecasts and while it might be theoretically possible for a place like Willcox or San Simon to get rainfall over 40% or less of the locality, the chances are very small given the small areal coverage of these towns. Even given the smaller size of our thunderstorms here in the SW US, I can't conceive of a situation where one wouldn't cover all of Lordsburg or Deming NM with measureable rain yet POPs of greater than 40% are rarely forecast for those locations at any time during the Summer. When I see a comment on a forecast that says "Chance of measureable rain 70 percent" I take that wording to mean just that and not that 70% of Sierra Vista will see rain.

Steve