My thoughts on the tropics….
As was the case with my summer forecast there are several features that come into play when dealing with the tropics this year. However, unless you have a background in meteorology it’s rather difficult to understand, and with me still trying to figure out how to use visuals in this blog it’s going to be difficult for me to try to explain it. lol So because of this I will keep things as simple as I possibly can and just focus on two of the main players….. 1) the developing El Nino and 2) the ocean temperatures in the tropical Atlantic Basin.
The developing El Nino
I posted a visual on my facebook page about a week ago showing how the temperatures in the tropical Pacific off of the coast of South America are starting to warm. The temperature departures compared to normal are already climbing to above normal levels. That’s the early stages of a developing El Nino. By definition El Nino, for reasons still fairly unknown to scientists, is a sudden warming of the tropical waters in the Pacific Ocean off of the coast of South America, Peru to be more exact. This tends to happen every 4 to 7 years.
The problem with this sudden warming is “Mother Nature” doesn’t like this. The Earth is comprised of 70% water, 30% land. Out of that 70% water a HUGE chunk of that is the Pacific Ocean. So naturally, when you change the temperature of a large body of water like this it’s going to have huge repercussions on the weather pattern farther down the road. The reason for this is because the ocean and the atmosphere as well as hemispheric patterns and the solar cycle are all interconnected. You change one, it then changes the other and so on and so forth. It’s like the domino effect.
When an El Nino develops the waters become warm enough to start lowering the air pressures (off of the coast of Peru). This intern strengthens the easterlies. The easterlies is a wind that blows from east to west across the Atlantic Ocean between the Equator and the Tropic of Cancer. Hurricanes do not like the easterlies because it tends to rip them apart by displacing the upper level features of the storm from the surface features. Hurricanes need symmetry, top over bottom. This allows the storm to continue to develop and strengthen. If this displacement occurs the storm cannot sustain itself and it collapses. So even though the El Nino is expected to be weak this summer it may end up being just strong enough to limit the amount of storms that develop within the Caribbean and the topical Atlantic waters.
The second feature is the temperatures of the ocean. A warm ocean is a hurricanes fuel so to speak. A hurricane needs ocean temperatures of at least 80 degrees or higher in order to even begin developing. Without it, you’ll get nothing more than just an unorganized area of showers and thunderstorms. You may think that with such a mild winter that the oceans would be warmer than normal this time of the year. However, the fact of the matter is, overall, the northern hemsiphere this past winter was VERY cold. It seemed like the United States was the only land area that experienced mild weather. It truly was one of the strangest things that I have ever seen during the winter months in the 12 years that I have been forecasting.
The cold winter for everyone else in the northern hemisphere really cooled off the ocean temperatures in the Atlantic. The waters around the Bahamas, the Caribbean and the equatorial Atlantic are all well below normal for this time of year. As a matter of fact, when it comes to the tropics the only areas that are above normal is the waters right off of the coast of the Mid Atlantic (storms never develop there anyway) and the Gulf of Mexico. So a cooler ocean means no fuel for storm development, no fuel for storm development means no hurricanes. With the ocean temperatures as cold as they are right now it may end up taking quite a while for them to warm up.
With the developing El Nino (strengthening easterlies) coupled with the cooler than normal ocean temperatures I think what we’re going to see here is a much quieter tropical season than what we saw last year. Now in terms of the number of named storms this year, I never make a call on that. Mainly because I sometimes feel the National Hurricane Center in Miami has it’s own agenda and tends to name every Tom, Dick and Harry storm out there for the sake of hitting their predicted numbers. So who knows how many storms will actually get named, but I can tell you this….the actual number of hurricanes this season (winds 74 mph or greater) should end up being lower than normal. Could we end up seeing a couple major hurricanes (cateogry 3 or higher)? Sure! Almost every year we do, but most of the time they stay out to sea and miss the United States.
AccuWeather, WSI and the National Hurricane Center are all going with a quieter than normal hurricane season this year. Based off of everything that I have just explained above along with other factors I see no reason to disagree with them. But I do want you to keep something in mind here. With the Gulf of Mexico as warm as it is, this could end up being one of those years where come August we suddenly get like 3 or 4 storms developing within a two week span down there. So I think it will end up being a quieter season overall with a sudden, quick burst in August (which is normal). I also would not be surprised if we get something developing during the month of June this year because of the temperatures of the Gulf, but again that does not mean it will be a busy season. It only takes one though. Last year there was only one hurricane to hit the US and that was Irene. Lets hope that one hurricane this year stays out to sea.
– Chris S.