A good example --
..is the Accu-Weather app available on the Kindle Fire. The near-term forecast mostly agrees with what A/W is saying, but it has a 15-day outlook that I'd guess is the raw output of some model, and can have wild and improbable figures. It'll show a day in that period with, say, a 20-degree departure from the previous day, and with the next forecast cycle, that variance may go away or swing the other way. Or it'll show 5 days of cold rain coming up, then a day later all traces of that are gone.
Here in the Northeast, even carefully constructed forecasts have trouble with 'back door' cold fronts and wind flow off the ocean -- the models usually have the marine air moving out at some point, but in reality it frequently takes much longer to break the pattern. Possibly because the models don't have enough data points over the ocean, or the algorithms underestimate the marine influence.
