Perfect Weather on the Net

ctwxman writes "Here in the East, we're having a heck of a weekend. The snow has been flying, accompanied by wind, accompanied by people on TV saying, 'stay home.' I'm one of those people. I forecast the weather for a living. It's a great job... a magnificent physics puzzle, solvable with high level math and some acquired skill. And, there's a new puzzle every day, tenuously linked to the one you solved yesterday. When I started doing this over 20 years ago, the data to accomplish the task was tough to come by. I remember how excited I got when I first was able to get data at 300 baud on a request/reply basis (I guess we call that interactive now). Now, nearly everything you need to forecast the weather is here, on the net. Yes, there are a zillion sites that already have the finished forecast, but this is Slashdot. We don't need no stinkin' forecasters!" Read on for ctwxman's notes on do-it-yourself weather forecasting.

ctwxman continues:

I always like to start at NCEP (National Centers for Environmental Prediction) for a look at the dynamic models. Each is run using somewhat different equations, making them often come up with different, quite contrary solutions. Some of these models, like the GFS are worldwide in their coverage and forecast out an amazing 16 days (note: the word accurately was not used in the last sentence). Once the dynamic models are through, we can massage them against past performance under similar circumstances at specific places. These are the statistical models, referred to as MOS (Model Output Statistic) models. Again, there are somewhat different solutions from different models. If none of these work for you, run your own. There are programs available to allow you to run your own model, specifying the domain, grid spacing, time interval, etc. The most commonly used research model of this type is the MM5, produced at Penn State University. Run it on your PC! Of course, it's freely available and supported. Sometimes, the data you want already exists, but not in the form you'd like to see it. That's where software like GrADS comes in. Put out by the Institute of Global Atmosphere and Society's Center for Ocean-Land-Atmosphere Studies, GrADS claims to be an 'interactive desktop tool that is used for easy access, manipulation, and visualization of earth science data.' I agree with all except 'easy.' I run a version of GrADS on my server in order to produce localized forecast graphics like this that wouldn't otherwise be available. Yes, looking at satellite imagery and radar is a lot of fun... but the real fun is knowing what will be there before you look. And, astoundingly enough, we are significantly more accurate (and I get assaulted significantly less often at the grocery store) than even a few years ago.

Comments

Re:Where's the raw data?

[aemain]

NOAA's National Climatic Data Center has a lot of the raw data available, most of it for free (especially if you're coming from a .edu domain). Both US and international data.

Re:Run your OWN weather station

[gnu-generation-one]

Even if you don't want to run a climate model, try putting XPlanet on your background, and get the updated cloud images every 3 hours.

It's a great way to stay informed about what's happening weather-wise around you, and you'll be able to watch the weather-forecasts with an "I guessed as much", from being constantly aware of the cloud pictures.

Re:Old wives tails

[Anonymous Coward]

The origin can be traced to the Bible (possibly before, but don't know of any reference):

Matthew 16:3:

He answered and said unto them, "When it is evening, ye say, 'It will be fair
weather: for the sky is red.'
And in the morning, 'It will be foul weather today: for the sky is red and
lowring.'"

Not only can the colour of the sky be affected by pressure fronts as pointed out in other places, but it can also indicate the movement of cold fronts. I suppose the 'sailor version' is more well known in the US because almost the entire population imigrated by sea... but the 'shepherd version' which is more well known in Europe, will pervade agricultural commuities more.