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Three problems: 1. Uncertainty isn't actionable. A statement like, "There's an 85% chance of snow with accumulation of 1–24" with peak probabilities of 28% and
by basseq 12y ago
Three problems:
1. Uncertainty isn't actionable. A statement like, "There's an 85% chance of snow with accumulation of 1–24" with peak probabilities of 28% and 17% at 2" and 18", respectively" is nonsense to most people. And moreover, it doesn't mean anything to me. Are we going to get snow that will affect my morning commute? Are we going to get so much snow that I need to take emergency action? A probability distribution doesn't answer those questions, even if that's the best that exists.
2. Weather is news. The cable news channels were dominated by snow predictions yesterday, and the Weather Channel exists as an "entertainment" venue, not a source of scientific information. If it doesn't fit into a soundbite, the public can't absorb it. And "Weather is hard to predict" doesn't garner viewership.
3. Prepare for the worst. While small changes in the environment can lead to large variability in snow accumulation, the fact of the matter is that there was a not-unlikely chance (according to the models) that NYC, Boston, and other cities could have seen crippling snowfall. They were able to prepare for that eventuality. That it didn't come to pass is almost a non-issue. Can you imagine the outcry—not to mention the impact—if the situation was reversed (i.e., surprise 3' of snow)? Fairfax County Public Schools outside of DC got slammed in the media for not closing a few weeks back.
The real question is: at what point of probability do you prepare for a potential outcome, and are you prepared to back that up (either way)? Do we prepare for record snowfall on 80% likelihood? 50%? 10%? (And as a broader point of discussion, this same calculation applies to other areas: TSA spend vs. terrorism; flood insurance cost vs. coverage; etc.)
- Goronmon 12y agothe fact of the matter is that there was a not-unlikely chance (according to the models) that NYC, Boston, and other cities could have seen crippling snowfall. They were able to prepare for that eventuality. That it didn't come to pass is almost a non-issue. The thing is, for the Boston area at least, the crippling snowfall totals came true. Areas west of Boston were reporting well over two feet of snow earlier in the day.
- emhart 12y agoYeah, southwest of Boston we are getting wrecked. Still coming down hard, hoping it finishes up soon. I'm glad we had the warnings, and I'll be particularly glad if we lose power, which seems pretty likely at this point, since the warning gave me the chance to stock up, charge battery backups, etc.
- mikeash 12y agoThe situation with Fairfax was quite different. The forecast there was pretty accurate: a couple inches of snow, falling on warm ground with rapidly cooling temperatures. To someone who understand this, that means the roads are going to be absolutely atrocious. Apparently whoever decides these things at FCPS thinks it means "that's not much snow, so we'll be fine."
- basseq 12y agoAgreed: weather forecasting was not the only thing at play. (I live in Fairfax, and it was also worse than forecasted.) This just illustrates what happens when you get it wrong (whether you are a school administrator, meteorologist, reporter, or policy maker).
- mikeash 12y agoYou're completely right. Regardless of who's to blame, the result was school busses in ditches and all sorts of other fun.
- VLM 12y agoThere is one practical uncertainty action that can be taken: I mostly get my forecast from a bookmark on weather.gov, and the "area forecast discussion" is one more click away. The technical discussion isn't any more complicated than sportscasting news once you get used to it, but that stuff doesn't matter, the important part is to read for "FORECAST CONFIDENCE IS HIGH." and "MODELS ARE IN GOOD AGREEMENT WITH" at which point you can pretty much trust the forecast for that time period, and if the textual commentary is all what wikipedia calls weasel word phrases like "SHOWING SOME DIFFERENCES" or "BUT MAY NEED TO BE RAISED IN LATER FORECASTS IF MODELS REMAIN CONSISTENT" means you need to check back in half a day or so, till they firm up a bit. The only verbal commentary you'll get in mass media reporting is how great lasagna recipes sound and how weather will impact the local ball team, which sucks. If AFDs could be a little more formalized by date, you could do automated textual analysis pretty trivially and produce an honest forecast. Sometimes weather guys can give you an accurate forecast for next thursday and sometimes they can't, but the monkey in the street DEMANDS some answer for next thursday, even if there really isn't one, even if it makes the weather guy look dumb. An interesting startup-ish idea would be a mostly automated honest weather report app where days when the best scientific minds output a question mark, are displayed as a question mark instead of just makin stuff up. It would be a nice difficult problem, sounds all startup-py to me.