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

math ?

[Anonymous Coward]

a magnificent physics puzzle, solvable with high level math and some acquired skill.

M2p...

I think weather forecast ain't anything to do with maths... Stop watching your screen trying to calculate what is (nearly) impossible to compute. Simple sky-watching, a few low-level basic instruments (measuring temperature and air pressure, mainly) will surely make better forecasts than the ordinary-TV-guy.
He's wrong too often...

Weather Stations?

[Xenothaulus]

Spend time outside. The more you do that, the more attuned you become to the weather and what it's going to do. Yes, I said outside. It's that place on the other side of the window by your desk.

Re:Old wives tails

[Anonymous Coward]

I thought it was sailor, not shepard.

I guess you're closer to the sheep than the sea.

Lookit

[UtilityFog]

One of the best pattern-detection and analysis systems out there is still the human visual cortex -- watch the radar for your area consistently and you'll soon start getting a feeling for what is going to happen next. Wunderground's regional is about the right size.

Re:Close, but no cigar

[ctwxman]

You're right that our accuracy goes down as we go farther into the future, but even having a small amount of additional insight into wind directions, barometric pressures, and the high and low temperatures is incredibly valuable. People live the weather in realtime. The fact that it was nice yesterday makes little or no difference if it's rotten today. But, some businesses and industries greatly benefit from knowing how and when to order and plan based on the coming weather. I actually present an 8 day forecast. I have gone on the air to explain what it does and doesn't do (and it doesn't do a lot). It has been fairly successful in showing temperature trends and less successful at everything else. But, knowing a cold snap will last... or not... has great value.