Score one for the weather forecasters. This time they definitely got it right.

We all know about the predicted snowstorms that never come or the blizzards that seem to come from nowhere. When that happens, the poor forecasters get teased . . . or worse.

But not this time.

Several days before the first snowflake fell, meteorologists saw the makings of a really big storm on their computer models. The people who study weather use computer models to help them with their forecasts.

Several times a day, weather information -- such as temperatures and winds -- from all over the world is entered into these models. The models then use that information, and some complicated math, to predict what the weather might be like for the next couple weeks.

The predictions come out in the form of maps and numbers. It's the job of the meteorologist to study this information and then come up with a forecast.

Around the middle of last week, some of the models began predicting that a huge storm would hit the Mid-Atlantic (that's us) and Northeast over the weekend. At first, forecasters couldn't say for sure the storm would come, since models sometimes show one thing one day and something else the next.

But as it got closer and closer to the weekend, all the models kept predicting the same thing -- one of the biggest storms ever for our area.

At right is a map from Saturday that was made by one of the models. Remember, we had a few inches of snow early Saturday but the big snow didn't start falling until very late Saturday. The colorful blobs show how many inches of precipitation were predicted to fall during the next two days.

The models assume all precipitation will fall as rain. Since snow piles up much higher than rain, forecasters multiply the amount predicted by about 10 when they know it will be cold enough for snow instead of rain.

Washington is in the middle of a red blob. According to the code below the map, being in the red zone meant that two to three inches of rain was expected. Multiplied by 10, that means 20 to 30 inches of snow. Which is just what many neighborhoods in the Washington area got.

-- Dan Stillman

A picture is worth a thousand snowflakes: In the Saturday computer model, the red segment over the Washington area indicated two to three inches of rain -- or 20 to 30 inches of snow -- were on the way.For Laura Waselewski, the snow in Waldorf was totally tubular on Monday.In Dale City, 7-year-old Mariah Kelly found that shoveling can be fun -- at least at first.