How many hurricanes? How strong might they be? The National Hurricane Center's predictions are out for the 2017 Atlantic Hurricane Season and NBC10 First Alert Weather chief meteorologist Glenn "Hurricane" Schwartz explains what it means to you.
Actually, It Already Started nNo one can be blamed for missing the first official Tropical Storm of the 2017 Atlantic Hurricane Season. Arlene formed and died a quick death WAAAAY out in the middle of the Atlantic back in April. Here is one of the official graphics from The National Hurricane Center (NHC) to give you an idea of just how far away from everything Arlene was.
June 1 is the official first day of hurricane season, but it’s just an arbitrary date. The season lasts until Nov. 30, but if a storm forms in December, it will still be considered part of the 2017 hurricane season.
Some of the names toward the end of the list are not likely to be used, since few years have seen us get through the whole list. This probably disappoints my newest co-worker, Tammie Souza. Even though the spelling is different, it’s a great thing to have a hurricane with your own name-especially for a meteorologist. For the record, there never has been a Hurricane Glenn, and certainly not an official Hurricane Schwartz. n When Will a Storm be Named After You?
About Hurricane Season nEven though the season starts in June, it’s typically a quiet month in the tropics. So is July. It really peaks from August through October, with the “peak of the peak” on Sept. 10. nThis makes it much safer to vacation in Florida, North Carolina or the Caribbean around the 4th of July than around Labor Day. The worst hurricanes tend to form during the peak months, but Sandy in 2012 hit when it was almost November. And the most destructive hurricane in Pennsylvania’s history was Agnes, in June 1972.
Hurricanes are unique types of storms, very different from the winter-type storms we get regularly. They are also quite different from nor’easters, even though they all have LOW pressure in the center, with winds circulating counter-clockwise around the center. They form in different ways, and strengthen for different reasons. For just about everything you need or want to know about hurricanes, check out the
main NHC site.
How Is the Current Pattern Setting Up? nSince hurricanes need warm water to develop, the ocean temperatures are followed closely. The minimum temperature needed for formation (approximately) is 79 degrees Faremheit. But in the tropics (and the rest of the world), the metric system is used. So the base water temperature is 26 degrees Celsius. nHere is the latest detailed ocean temperature map: The 26-degree line is pretty clear. And it shows that all of the Caribbean, the Tropical Atlantic, and most of the Gulf of Mexico are already warm enough to support hurricane formation.
A more detailed look, above, shows that much of the water off the Southeast Coast of the U.S. is warm enough for tropical storm formation. The yellow and orange colors show the warm “Gulf Stream” clearly. This area often helps tropical systems form, and intensify the ones that have already formed, and track over it. The map also shows why tropical storms and hurricanes don’t form north of North Carolina: the water is just too cold. And even though the ocean keeps getting warmer during the summer, it rarely gets to 79 degrees even at the warmest point of late summer.
Superstorm Sandy took advantage of unusually warm late-season ocean to intensify in the Atlantic, and to stay strong even as it moved north of the Gulf Stream. It tracked across areas of record warm ocean temperatures for that late in the season.
Of course, it takes much more than a warm ocean for hurricanes to form. Tropical waves coming off Africa and stalled fronts in the Bahamas are among several “sparks” to help such storms form. Winds above the storms need to be relatively light, leading to less “shear,” which would blow the tops off the growing storms. It takes a precise combination of ingredients, just like a kitchen recipe. One bad ingredient can ruin the dish. And, for example, too much African dust can ruin a Tropical Storm formation. That’s why there are so few of them. Here is the first month of hurricane season.
This is what it looks like at the peak of the season. Areas of formation and movement are clearly shown.
One Big Change From NHC nSuperstorm Sandy was, unfortunately, a perfect example of one of the biggest flaws in hurricane communication. Sandy had “weakened” according to measurements of wind and pressure, but the seas were still building offshore. When it hit, the storm surge (inundation from the ocean) was a tragic surprise to many. nNow, NHC has created a new product to help separate the potentially deadly storm surge from variations in hurricane category. It’s called a “Storm Surge Watch or Warning.” Even if a hurricane has weakened officially, if the storm surge is still expected to be major, a watch or warning will be issued.
We’ll keep you updated throughout hurricane season, with the latest computer models, ocean temperatures, and other “inside” information on what to expect.