Predicting Storms

One of the reasons I decided to become a reporter was because I liked to ask questions. Not the confrontational, prosecutor style, “Are you guilty of…?” type of questions. Believe me, I’ve asked those types of questions when needed. But I prefer the, “So how does this work?” or “What does this do?” type of question. I’ve always been a curious person.

National Weather ServiceSo when I was standing in the middle of the National Weather Service office in Morehead City, surrounded by banks of computers, I had to ask the question, “With all this technology, how can we not know when a hurricane will form?”

That made the meteorologists in the office laugh. Apparently, it’s the question that almost every reporter asks.

“You’d think we could pin it all down, and know exactly what will happen, and we do have models of what will likely happen, but weather forecasting is still not an exact science,” said David Glenn, a meteorologist at the NWS office.

Here’s what we know.

Meteorologists keep their eyes and instruments trained on Africa, because it turns out a thunderstorm in Africa could be the key to figuring out why hurricanes form. That’s because about seven to ten times per year, a cluster of thunderstorms rolls off the west coast of Africa and over the Atlantic Ocean, in the direction of the United States. Scientists have dubbed the storm clusters “tropical waves.” And it turns out about 85% of all major Atlantic hurricanes start out as “tropical waves.” But this is where the science isn’t exact.

National Weather ServiceOnly one out of ten of those clusters ever turn into a hurricane because the conditions have to be just right. What scientists know is that the ocean water temperature needs to be about 80 degrees. There must be high pressure in the upper atmosphere; about 1000 millibars or higher when the system begins. The winds aloft need to be weak so the top of the system isn’t sheered off. As for moisture, Glenn says many times thunderstorms develop as a storm starts evolving, so there are heavy rains before the system even has a closed low-pressure system.

But even all of that science has limitations. Scientists still don’t understand why most of the tropical waves don’t turn into anything. It’s not known just what turns the switch on to make the storm a hurricane. Or in cooking terms, nobody knows what the final ingredient is that transforms a wave into a hurricane. Glenn admits, for all the technology, scientists may never know for sure.

But they will keep searching.

- Frank Graff

Frank Graff is a producer/reporter with UNC-TV, focusing on North Carolina Science Now, a weekly science series that airs Wednesdays, beginning in August 2013, as part of North Carolina Now on UNC-TV. In addition to producing these special segments, Frank will provide additional information related to his stories through this North Carolina Science Now Reporter's Blog!

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