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Meteorologist

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Hi, I'm your new meteorologist and a former software developer. Hey, when we say 12pm, does that mean the hour from 12pm to 1pm, or the hour centered on 12pm? Or is it a snapshot at 12:00 exactly? Because our 24-hour forecast has midnight at both ends, and I'm worried we have an off-by-one error.
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Cognoscan
235 days ago
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Pedantic answers to the Mathematician's questions on what precipitation chance means: https://www.weather.gov/ffc/pop
If you know the meaning of the probability, you can answer the rest of his questions. The area one is basically a non-question: any forecast on weather.gov will show you the forecast area.

And for the question unasked: how do you end up with phrases like "scattered" or "this morning" in a forecast? NOAA again has you covered: https://www.weather.gov/bgm/forecast_terms
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ericprasmussen
235 days ago
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hell yeah
francisga
236 days ago
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Panel 1 is a real legit question I have always had about what "percent change of precip" means in weather forecasts. Please help.
Lafayette, LA, USA
Cognoscan
235 days ago
NOAA actually has a succinct explanation for part of this: https://www.weather.gov/ffc/popThe short of it is this: there is a X percent chance that rain will occur at any given point in the area over the next hour, independent of the other hourly predictions. This extrapolates to the daily forecast as well, which does have hourly bounds (though I forget what they are).
fancycwabs
235 days ago
For a while the local meteorologist changed it from 30% chance of rain to 30% *coverage* of rain, meaning for the viewing area 30% of it was getting rain. I assume that's still what they use even though they switched back to "chance."
fancycwabs
235 days ago
Although this was in Mobile, Alabama, and a 30% coverage of rain meant that you were gonna get wet.
rraszews
234 days ago
Or, at least, 30% of you would. But yeah, the way the husband of a meteorologist I used to work with explained it, "30% chance of rain" means, roughly, "It's going to rain somewhere. It's a 30% chance it'll be on YOU" (Though that is just how he put it. Technically, "30% chance" could mean "It's definitely going to rain, and 30% of the area will get it" or equally "It's only 1-in-3 that it will rain, but if it does, it will rain EVERYWHERE" But these two possibilities come out to the same thing assuming you are a stationary object within the area which is small enough that you can not meaningfully be "half-rained on"
alt_text_at_your_service
236 days ago
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Hi, I'm your new meteorologist and a former software developer. Hey, when we say 12pm, does that mean the hour from 12pm to 1pm, or the hour centered on 12pm? Or is it a snapshot at 12:00 exactly? Because our 24-hour forecast has midnight at both ends, and I'm worried we have an off-by-one error.
davidar
235 days ago
12PM can't be 12:00 exactly, because then it wouldn't be PM, it'd just be M
alt_text_bot
236 days ago
reply
Hi, I'm your new meteorologist and a former software developer. Hey, when we say 12pm, does that mean the hour from 12pm to 1pm, or the hour centered on 12pm? Or is it a snapshot at 12:00 exactly? Because our 24-hour forecast has midnight at both ends, and I'm worried we have an off-by-one error.