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Just what does a 60% chance of rain mean?
dgk writes:
On Wed, 5 Aug 2009 09:17:59 -0700, "Terry Neff" wrote: "dgk" wrote in message . .. Does it mean that somewhere within 100 miles of me there is a 60% chance of rain falling, or does it mean that there is a 60% chance that I'm going to get rained on (assumimg that I'm outside)? I'm not a big fan of biking in the rain, although being around 90F today I sort of am looking forward to it. I ran into a story about this a few months back and learned something new from it. Apparently it is intended to indicate neither the _percentage of different locations_ within the named area which are expected to get wet that day, nor the _percentage of time_ any given location might get wet on that day. Rather, it is intended to indicate the _percentage of different days_, each having the same atmospheric conditions, when rain will fall somewhere within the named area. And apparently then that means that on (100 minus _that percentage of days_) no rain will fall anywhere within that area. [...] Ok, so all it is telling me is that there is a 60% chance of rain somewhere in the area. Actually, it has dropped to 40%. I'm very likely not to get wet, at least by rain. I believe it means that there is a 60% chance of measurable rain at any given point in the forecast area (it's assumed that the probability is equal everywhere in the area). From http://www.srh.noaa.gov/ffc/html/pop.shtml : The "Probability of Precipitation" (PoP) describes the chance of precipitation occurring at any point you select in the area. How do forecasters arrive at this value? Mathematically, PoP is defined as follows: PoP = C x A where "C" = the confidence that precipitation will occur somewhere in the forecast area, and where "A" = the percent of the area that will receive measureable precipitation, if it occurs at all. So... in the case of the forecast above, if the forecaster knows precipitation is sure to occur ( confidence is 100% ), he/she is expressing how much of the area will receive measurable rain. ( PoP = "C" x "A" or "1" times ".4" which equals .4 or 40%.) But, most of the time, the forecaster is expressing a combination of degree of confidence and areal coverage. If the forecaster is only 50% sure that precipitation will occur, and expects that, if it does occur, it will produce measurable rain over about 80 percent of the area, the PoP (chance of rain) is 40%. ( PoP = .5 x .8 which equals .4 or 40%. ) In either event, the correct way to interpret the forecast is: there is a 40 percent chance that rain will occur at any given point in the area. |
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#12
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Just what does a 60% chance of rain mean?
"Frank Krygowski" wrote in message ... On Aug 5, 8:36 am, dgk wrote: Does it mean that somewhere within 100 miles of me there is a 60% chance of rain falling... No. It means that after hearing the forecast, there's a 40% chance you'll stay inside. |
#13
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Just what does a 60% chance of rain mean?
"dgk" I'm not a big fan of biking in the rain, although being around 90F today I sort of am looking forward to it. It could rain on 60% of the road. Thinking from left to right you need to stay on the right 40% and you should be OK. Good Luck Burr |
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Just what does a 60% chance of rain mean?
Leo Lichtman wrote:
"dgk" wrote: (clip) being around 90F today I sort of am looking forward to it. ^^^^^^^^^^^^^^^^^^ Normal body temp is 98.6F. You may be dying. Just for laughs and giggles, I wake up fully functional at 95 degrees (F) but if I am riding and hit a cold front and drop to that I can't ride over 5 MPH. I had to have some bored firefighters pick me up once when the temperature dropped from 70 to 55 in about 45 minutes and I was going into hypothermia. I forgot to eat that day and had already done a lot of miles in the mountains. They just warmed me up, joked with me, and took me home, no problem since there were no serious calls that night. Bill Baka |
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Just what does a 60% chance of rain mean?
On Fri, 07 Aug 2009 05:11:29 -0700, Bill Baka wrote:
Leo Lichtman wrote: "dgk" wrote: (clip) being around 90F today I sort of am looking forward to it. ^^^^^^^^^^^^^^^^^^ Normal body temp is 98.6F. You may be dying. Just for laughs and giggles, I wake up fully functional at 95 degrees How do you know this, Bill? (F) but if I am riding and hit a cold front and drop to that I can't ride over 5 MPH. I had to have some bored firefighters pick me up once when the temperature dropped from 70 to 55 in about 45 minutes and I was going into hypothermia. I forgot to eat that day and had already done a lot of miles in the mountains. They just warmed me up, joked with me, and took me home, no problem since there were no serious calls that night. Do you *really* expect people to believe bull**** like this? Really? You actually think you'll go into hypothermia in 55 degrees, while riding a bicycle? Quit trying to blow smoke up people's asses, Bill. You're nothing but a blowhard teller of tall tales, and not even good at it. -- "Ubuntu" -- an African word, meaning "Slackware is too hard for me". Need help? -- http://brandybuck.site40.net/pics/ubuntu.jpg The Usenet Improvement Project: http://improve-usenet.org Get a job! -- http://brandybuck.site40.net/pics/republican.jpg |
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Just what does a 60% chance of rain mean?
Dan C wrote:
On Fri, 07 Aug 2009 05:11:29 -0700, Bill Baka wrote: Leo Lichtman wrote: "dgk" wrote: (clip) being around 90F today I sort of am looking forward to it. ^^^^^^^^^^^^^^^^^^ Normal body temp is 98.6F. You may be dying. Just for laughs and giggles, I wake up fully functional at 95 degrees How do you know this, Bill? I keep a bedside digital thermometer just to see how relaxed I get while sleeping. (F) but if I am riding and hit a cold front and drop to that I can't ride over 5 MPH. I had to have some bored firefighters pick me up once when the temperature dropped from 70 to 55 in about 45 minutes and I was going into hypothermia. I forgot to eat that day and had already done a lot of miles in the mountains. They just warmed me up, joked with me, and took me home, no problem since there were no serious calls that night. Do you *really* expect people to believe bull**** like this? Really? You actually think you'll go into hypothermia in 55 degrees, while riding a bicycle? Yes, moron. I didn't eat that day and was out of useable energy so I was only barely pedaling at 6 to 8 MPH at 10 P.M. after the sun had left me. Quit trying to blow smoke up people's asses, Bill. You're nothing but a blowhard teller of tall tales, and not even good at it. I can't help it you are stupid. Stupid is not curable. Mild hypothermia is. Bill Baka |
#17
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Just what does a 60% chance of rain mean?
Bill Baka wrote:
(F) but if I am riding and hit a cold front and drop to that I can't ride over 5 MPH. I had to have some bored firefighters pick me up once when the temperature dropped from 70 to 55 in about 45 minutes and I was going into hypothermia. I forgot to eat that day and had already done a lot of miles in the mountains. They just warmed me up, joked with me, and took me home, no problem since there were no serious calls that night. Do you *really* expect people to believe bull**** like this? Really? You actually think you'll go into hypothermia in 55 degrees, while riding a bicycle? I've ridden quite a lot at that temperature. I find that 55 is the point at which I start to need a windbreaker. My particular ride is six miles, mostly downhill, before sunrise. The couple of times I forgot the jacket, I found myself shivering by the time I reached my destination. Yes, moron. I didn't eat that day and was out of useable energy so I was only barely pedaling at 6 to 8 MPH at 10 P.M. after the sun had left me. If Bill's ride was longer than mine, at a different level of strenuousness, or maybe the humidity or wind was a little more severe, or if his metabolism is a little different than mine or had been thrown out of whack by a lack of ready carbs, I can see how hypothermia could have ensued. Quit trying to blow smoke up people's asses, Bill. You're nothing but a blowhard teller of tall tales, and not even good at it. Note to Dan C : If you find Bill Baka's "tall tales" so onerous, I recommend that you activate your twit filter, or just plain ignore him. That will free you of the terrible burden of having to endure his posts. The rest of us will somehow endure without you to police the group for us. Personally, I find that most of Bill's posts lie somewhere along a line between "interesting" and "possibly remembered in an exaggerated way." Your posts, OTOH, lie squarely on "obnoxious." Frumious __o | Profanity and obscenity entitle people who don't _`\(,_ | want unpleasant information to close their ears (_)/ (_) | and eyes to you. - Kurt Vonnegut |
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Just what does a 60% chance of rain mean?
On Aug 5, 7:36*am, dgk wrote:
Does it mean that somewhere within 100 miles of me there is a 60% chance of rain falling, or does it mean that there is a 60% chance that I'm going to get rained on (assumimg that I'm outside)? I'm not a big fan of biking in the rain, although being around 90F today I sort of am looking forward to it. It means that the forecast location has a 60% chance of getting a trace of precipitation during the forecast period. Above 55F or so, getting wet from no salt rain is preferable than sweating from rain gear. |
#19
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Just what does a 60% chance of rain mean?
In article ,
dgk writes: Does it mean that somewhere within 100 miles of me there is a 60% chance of rain falling, or does it mean that there is a 60% chance that I'm going to get rained on (assumimg that I'm outside)? It means: if you head out wearing the worst possible clothing for rain, it's gonna rain. But if you prepare for rain, it won't. A 50 % chance means: you stick your head out the door to check the weather, see that it's raining, and prepare for it. When you step out, it stops raining. So you go back inside, prepare for dry weather, step out again, and it's raining again. Rinse & repeat. I'm not a big fan of biking in the rain, although being around 90F today I sort of am looking forward to it. Sometimes folx washing their cars at the curbside are happily willing to give a rider a refreshing, zesty spritz from their garden hose, when politely requested to do so. If there's no lawn-sprinkling ban going on, it can be pleasant to ride through any sprinkler overspray. Maybe circle back and do it again. And again. cheers, Tom -- Nothing is safe from me. I'm really at: tkeats curlicue vcn dot bc dot ca |
#20
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Just what does a 60% chance of rain mean?
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