Simulations

At 2 o'clock on a recent June afternoon, a group of golfers were glued to the Weather Channel® on a TV on Hilton Head Island, South Carolina. They had little better to do since the Oyster Reef golf course had been closed and cleared when the National Weather Service issued a severe thunderstorm warning for nearby Savannah, Georgia, a half-hour earlier. They could hear reverberating booms of thunder off in the distance, and the sun was a pale disk through the fringe of the storm's anvil top.

One golfer went to the clubhouse desk and observed to the manager that the golf course was in Beaufort County, South Carolina, and not Savannah. The manager retorted that the warning was for Savannah and nearby coastal waters, and in his opinion, the golf course abutted such coastal waters. The course would stay closed until the warning ended at 2:30 P.M. or was called off.

Back at the TV, a consensus based on Weather Channel® radar animations was growing that the feared storm appeared to be going by to the south and missing the golf course. It had blown out windows and flattened trees in downtown Savannah, but the only effects at Oyster Reef so far were that muffled thunder could be heard and no golf could be played. Within a few minutes, the dozen or so golfers watching the TV had informally agreed that the short-term forecast for Oyster Reef was "no thunderstorms." Although a meteorologist (one of the authors) happened to be present, the forecast was made strictly by nonmeteorologists. The forecast verified, but perhaps the golfers did not appreciate the possible dangers. While most lightning occurs under the cumulonimbus thunderstorm cloud, most does not equal all. There are periodic reports in the news about someone being struck and killed by lightning when they thought the storm had passed. Of course, the only direct evidence that the person believed the storm would pass was that he was still on the course when he was struck. Golfers are often the tallest objects on open parts of a course, and their metal clubs can be an attractive target. The recent demise of metal spikes probably makes little difference; the change was made to protect golf courses, not to avoid lightning.

Like the golfers, watchers of today's weather reports on TV, with sophisticated satellite pictures and extensive radar coverage, can decide on their own what to expect in the next few hours. All that is needed is to determine where you are on the map, then see where the precipitation is moving.

But surely there is more to forecasting than watching where something is moving now and extrapolating to some time in the future. This chapter's topic is unit 3's central question: How are weather forecasts made?

In this chapter, you will learn how you can participate in the kind of forecasting done at the golf course. You will also discover how a far wider range of forecasts is made, and you will be in a position to judge the likelihood of success of most forecasts you hear or see. In addition, you will learn why some forecasts turn out to be spectacularly accurate while others seem so far off the mark they appear to have been made for another planet.

Using Forecasting Tools in a real Weather Situation simulation (7543.0K)