weather predictions

[all thumbs]

we all watch or listen to weather reports. My question is when they say 40% chance of rain, are these the odds? Or do they mean 40% of the forcasted area will have rain? Any ideas?

 

[one more cast]

Re: weather predictions

I was told by our local weather reporter that they are forcasting that 40% of the area should expect rain. I think it means that they have a 40% chance of getting it right.

 

[Terry H]

Re: weather predictions

Weather reports is about history. When they say 40% chance o' rain, what they are really saying is that in the past when these particular conditions existed, 40% of the time it rained, and 60%of the time it din't. I wish they would just say 60% chance of no rain. Chief

 

[roscoe]

Re: weather predictions

40% of the forecast area will get some rain ( a measurable amount) in the prescibed time period.<br /><br />So if they say 40% chance of rain tomorrow, it means that 40% of the area that is their veiwing area, will get rain. <br /><br />It could be that 40% of the area will get an hours worth of rain, or that 30% of the area will get an all day soaker and that 10% of the area will get a shower as the storm moves out of the area.<br /><br />This from Paul Joseph, meteorologist for WTMJ Channel 4 in Milwaukee.

 

[BoatBuoy]

Re: weather predictions

From www.noaa.gov:<br /><br />The National Weather Service defines the probability of precipitation as "The likelihood of occurrence, expressed as a percent, of a precipitation event at any given point in the forecast area during the forecast period." Further, a precipitation event: is formally defined as "The occurrence of a measurable amount (greater than .01 inches) of liquid (or liquid equivalent if frozen) precipitation during the forecast period (our forecasts are usually 12 hour periods)." <br /><br />Forecasts are usually given for a city, county, or a metropolitan area. The bottom line is that a 40% chance of rain for an area means that there is a 4 in 10 chance of getting some measurable precipitation in at lease some part of the area. Some parts of the area may get wet while others may not; or no part may get wet as there is a 6 in 10 chance of no precipitation.

 

[NYMINUTE]

Re: weather predictions

It is simple: 40% chance they are correct. What is the difference in partly cloudy, or partly sunny??

 

[kenimpzoom]

Re: weather predictions

They are only correct 50% of the time, though there's only a 10% chance of that. <br /><br />Ken