Long-range weather forecasts....why??

[SoonerDave]

This is perhaps an odd question, directed more towards the weather types that pass by these boards, but if anyone has any thought feel free to jump in...

I was browsing one of what seems to be a zillion weather-related websties, and see more and more of them trying to trumpet a detailed 15-day (or more) weather forecast, right down to sun/rain chances, high/low temps, the whole bit.

While I'm no meteorologist, living a lifetime in Oklahoma has taught me that trying to forecast the weather even two or three days ahead is, at best, problematic. You're dealing with an essentially infinite set of variables, any one of which could throw a forecast into the junkpile. My question is this - why would any weather organization try to create detailed forecasts of weather over two weeks away?

Now, don't misunderstand me - I'm not talking about 30-day outlooks for average temperature and rainfall. I'm talking about something I saw (as an example) at Accuweather.com that was an option to see a 15-day daily forecast for whatever city you happened to be browsing. Is it purely a marketing tool?

I know that NOAA doesn't really even attempt such a thing - for longer-range forecasting, they generate "probability maps" for above/below average rainfall and temperature over general regions, not "it's going to be cloudy and rainy in Memphis in two weeks."

I guess I'm just wondering the value of a specific forecast like that, because (as an example) I'm not going to cancel or reschedule some big outdoor event because a two-week-out forecast calls for rain. I just don't see where there's value in such an animal, except purely for curiosity's sake...

Thoughts?

-sd

[jsibelius]

I suspect it's probably helpful to farmers, although never having farmed anything more than a single soybean in my life, that's only a guess. I don't mind having a guess at the weather about the time I'm getting ready to leave on vacation. It doesn't mean I'm going to get upset at anyone if the weather isn't exactly as predicted when I return in 10-12 days, but it's nice to have an idea if there's an inkling of rain in the forecast or if it's more "bone dry" for the foreseeable future, as we have seen for many summers past.

[metro]

call me crazy, but I think farmers use the farmer's almanac and it tends to be more accurate than weather forecasts.

[OUman]

Only because they can. It's ridiculous to even attempt a 15-day forecast, but there are some weather models that allow for it and so they use those to do the forecasts. Most of the short to medium range models are good for only 3-4 days out, after that the accuracy levels go down with each day.

[SoonerDave]

Only because they can. It's ridiculous to even attempt a 15-day forecast, but there are some weather models that allow for it and so they use those to do the forecasts. Most of the short to medium range models are good for only 3-4 days out, after that the accuracy levels go down with each day.

That's sure more in keeping with what I understood to be the case with most of those weather models - heck, beyond 4 days the models rarely agree on much. At that point, which model do you choose?

This pretty much verifies what I thought was the case, but I thought I'd ask in case there was actually some value in a 15-day forecast (heck, even 10 is pretty iffy), but it sounds to me like it is a forecast for forecast's sake only.

[BabyBoomerSooner]

We've had the Farmer's Almanac for years and it provides weather forecasts a year in advance. Isn't it based on moon phases and folklore (like the thickness of animal's coats and caterpillar fur, etc.)? If we've placed so much trust in a book that's basically conjecture, it doesn't surprise me when I see the super extended forecasts by today's "weather scientists". When it comes to weather forecasting we're suckers.

[venture]

AccuWeather...shiver. They are a worthless organization and have been pushing for the National Weather Service to go away - at least for issuing any forecasts/etc to the public.

Granted we could be in San Deigo where the forecast isn't that hard. However, Oklahoma weather is crazy as we all know. Some will say, like last week, that we were suppose to be totally dry and then it was storming. A lot of it comes down to forecasters looking at the data and taking a bet...even though we may only be 1 or 2 items away from having a totally different out come. The wonderful cap we normally have to put up with here during storm season is a big one.

Dave you probably know most of these sites, but for those that don't I'll throw some nice links out.

NWS Norman, Oklahoma - Enhanced Weather Page <- A must as the Norman office is amazing with the detail they give.
Storm Prediction Center <- Severe weather forecasts for current day up to 8 days.
Weather Analysis Page <- College of DuPage has a really nice site.
4.0 km NMM WRF Precipitation Graphics <- High-Resolution forecast model for the region.
CASA Reflectivity Animation using Javascript Image Player <- New radar test system SW of the Metro...4 smaller radars providing better detail view of storms.
WDSS-II: NWRT Phased Array Radar <- Phased-Array radar test bed in Norman
National Weather Service Text Product Display <- What the Norman NWS Office is actually thinking behind their forecasts.