Duke
MegaDork
7/7/20 7:25 a.m.
ShawnG said:
Wife and I each have a different weather app on our phone.
Each day, the forecasts are different from each other, some days they're completely opposite.
My favorite is when the summary and detail within the same app don't even agree with each other.
I usually use Weather Underground, TWC, and Weatherbug, then kind of mentally average the results.
rustybugkiller said:
Tv weatherman: I think it's the only job that you can get wrong every day and still have a job.
if ANYONE, and I mean ANYONE thinks they are right more than 50% of the time, for a career may I suggest the stock market?
I think the one thing most people forget about forecasts is that they're for an area, not a location. If they say 50% chance of showers, they mean that there's a 50% chance that somewhere in the forecast area, there will be some precipitation. It won't necessarily rain where you are, but if it does across town, that counts. Especially in more rural areas, there won't be town specific forecasts, other than maybe some temperature adjustment algorithm for if one town is higher up and tends to be cooler or something like that.
In reply to RX8driver :
That's not quite what I've heard...
My understanding is yes, it's for an area. But a 50% chance of rain means that 50% of a particular area will have rain, and 50% of the same area will not.
That could mean they are very accurate.
Peabody
UltimaDork
7/7/20 8:14 a.m.
Pete. (l33t FS) said:
rustybugkiller said:
Tv weatherman: I think it's the only job that you can get wrong every day and still have a job.
Parts counter guy?
See also: Police, teachers, and HR professionals
My uncle, Alfred Blackadar, was one of the top meteorologists in the world.
Tribute to Dr Alfred K Blackadar
He actually helped IBM create complicated predictive modeling by writing programs that predicted weather to demonstrate the calculating capacities of a computer (weather prediction was one of the more complicated predictive models to create).
He built a weather station in his basement. Built his own computer in the early 70's (it was a scaled down mainframe- prior to PCs).
I remember him spending countless hours in that basement running calculations, predictive modeling etc. When he was all done, he would walk outside, hold out his hands and look up to see if it was raining.
He was pretty critical of weathermen who apparently didn't even have a window in their office.
I have a foolproof way of predicting summer weather. If I drive the van to work, there is 0% chance of storms. If I drive the Miata, there is 50% chance of storms. And if I ride the motorcycle, there is 90% chance of storms. Never fails.
Mndsm
MegaDork
7/7/20 9:00 a.m.
I'm lucky. Florida is the same. Hot as berkeley, so humid you sweat looking out the window, and it's gonna rain at 3pm.
trucke
SuperDork
7/7/20 9:17 a.m.
My friends daughter ws complaining about this last weekend. She was mowing their 10 acre property when it started pouring. She pulled out her phone and checked the weather...clear and sunny...right now! No rain in the forecast!
In reply to ¯\_(ツ)_/¯ :
Garbage In = Garbage Out.
Everyone who is claiming they are more accurate than the weather man, let's see you actually do it.
Otherwise, I'm with ProDarwin this sounds like a bunch of grump old men literally yelling at the clouds.
secretariata (Forum Supporter) said:
In reply to ¯\_(ツ)_/¯ :
Garbage In = Garbage Out.
This is really the issue, although it's not so much garbage in as too little data to put into the models. The world is huge, and there are incredibly few weather stations that feed data into the prediction models. Even in the US, there might only be three or four stations in a state, and the weather between them can change dramatically. So regardless of how good the models are, there just isn't enough data input for super accurate predicting.
In college I did several coop terms with a company developing lidar systems for satellites, basically you shoot a laser pulse at the earth, collect and analyze what gets reflected back and you can figure out wind speed, temperature and other data at multiple altitudes at a point on the earth. The ultimate goal was to have a large network of these in space taking thousands of measurements a day to feed into the models. We had trouble getting funding because at the end of the day, despite what most people think, we're already very good at predicting the weather several days out, and increasing the accuracy doesn't really make much of a difference in planning day to day activities the vast majority of the time.
jgrewe
Reader
7/7/20 11:59 a.m.
I can't believe no one has brought up the most accurate tool out there. Just get yourself a Weather Rock.
Weather.gov is the favorite of every pilot I know.
This reminds me, whats the deal with airline food?
I used to work in TV, and once asked one of our local weathermen how accurately can he really predict, and how far ahead. He said, "accurately, about 10 minutes, give or take 10 minutes."
racerdave600 said:
I used to work in TV, and once asked one of our local weathermen how accurately can he really predict, and how far ahead. He said, "accurately, about 10 minutes, give or take 10 minutes."
Yep, year before last we were in a situation where it was nice and sunny at our house in the NW side of town, south side of town had a tornado ripping through a commercial area.
Weather.gov is just the facts. AccuWeather is another no-nonsense forecast.
TWC actually biases their forecast in favor of higher rain chances. Their motive is, they'd rather predict rain and have it not happen than do the opposite and alienate the viewership.
But a 50% chance of rain means that 50% of a particular area will have rain, and 50% of the same area will not.
Not quite the right meaning. 50% chance of rain means that, in the past, the conditions in the forecast area have led to rain 50% of the time. Everybody might get it, everybody might not, or any percentage of people in between.
Forecast accuracy can vary wildly depending on the conditions, as mentioned above. When you get a Bermuda high parked off the mid-Atlantic region, you can nail the forecast for the next 5 days. If you're on the edge of a jet stream dip, the weather can be very different over a 50 mile path. Wintertime is the worst - you get the temperature wrong by 1° and it's the difference between a cold rain and 12" of snow!
ShawnG said:
At least you get to make up a cool weatherman name for yourself like "Stormy Showers"
I’m surprised that no female weather forecaster has taken the name Gail Force yet.
11110000 said:
Weather.gov is just the facts. AccuWeather is another no-nonsense forecast.
TWC actually biases their forecast in favor of higher rain chances. Their motive is, they'd rather predict rain and have it not happen than do the opposite and alienate the viewership.
But a 50% chance of rain means that 50% of a particular area will have rain, and 50% of the same area will not.
Not quite the right meaning. 50% chance of rain means that, in the past, the conditions in the forecast area have led to rain 50% of the time. Everybody might get it, everybody might not, or any percentage of people in between.
This was always my understanding, but I've heard both explanations from different meteorologists on the television. Probably would be good to understand which metric is being used.
OK, technically no one in this thread is correct regarding probability of rain (including me)...
The American Meteorological Society defines it like this:
Probability of precipitation is the forecast of >0.0254 cm (0.01 in.) of liquid equivalent precipitation at a specific point over a specific period of time. The term should not be confused with such concepts as the probability of precipitation over some portion of an area or the probability of precipitation over all of an area (larger than a point). If a POP of x percent were issued for an area, such as a county, that would mean the POP was valid at each and every point in the area. When alternate definitions are used [e.g., probability of precipitation > 1 cm (0.394 in.)], the event being forecast needs to be clearly specified.
But the National Weather Service defines it like this:
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 measurable 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%. )
And if you;d like to be a little more confused, ask a weatherman:
Meaning of a Chance of Rain
Looks like it can mean almost anything a local weather broadcast chooses for it to mean.
jgrewe said:
I can't believe no one has brought up the most accurate tool out there. Just get yourself a Weather Rock.
Another vote for the Weather Rock. You yourself can purchase one of these amazing instruments at most any Cracker Barrel Old Country Store.
I thought I would update after my vacation.
On Saturday I checked what Sunday predicted while I was in Watkins Glen. It said high of 99, mostly sunny, 12mph gusts, 10% chance of rain.
Actual Sunday weather: High of 89, thunderstorms with winds in excess of 60 mph, and hail.
They missed.
Curtis73 (Forum Supporter) said:
I thought I would update after my vacation.
On Saturday I checked what Sunday predicted while I was in Watkins Glen. It said high of 99, mostly sunny, 12mph gusts, 10% chance of rain.
Actual Sunday weather: High of 89, thunderstorms with winds in excess of 60 mph, and hail.
They missed.
You should have given us your prediction before you went.
In New Orleans when I was growing up we had a weather man named Nash Roberts. Nash was actually on the meteorological team that predicted the weather for D-Day, as in 6 June 1944. The invasion was postponed by one day because of people like Nash, the day before had really bad weather pop up and it would have ruined the invasion.
Nash was an expert on weather, especially hurricanes, something New Orleans people always feared considering the many times hurricanes hurt the city badly. The major oil companies had him under contract as their weather expert.
On multiple occasions he made a different prediction for a hurricane path than the national weather service. He was always right. Man was genius, the people of New Orleans revered him and the older people who remember him still do.
In reply to ¯\_(ツ)_/¯ :
GI,GO
Edit - someone beat me to it :=/