You’ve heard about El Nino, of course -- those warmer-than-average Pacific Ocean waters. Those can influence our hurricane season be creating upper level winds which cross Central America and interrupt the formation of tropical storms in the Caribbean. El Nino in the Pacific actually helps keep our storms to a minimum.
But then there is the new Nino! Scientists have only recently began studying what they are calling the “Atlantic Nino” -- a not-so-distant cousin even though it’s halfway around the world! Here’s a look at sea surface temperatures across the oceans:
I’ve circled and labeled the two Nino cousins:
This Atlantic Nino represents warm, equatorial waters in the far eastern Atlantic. That, simply put, gives rise to more tropical storms and hurricanes in the region (called Cape Verde hurricanes). The importance of that is the storms that form that far out spend lots of time over warm water crossing the Atlantic and become some of our most powerful storms. Hurricane Ike in 2008 was a Cape Verde hurricane. Here’s the track they take around the Bermuda high (which is called the subtropical ridge in this graphic):
Accordingly: Tropical cyclones that develop here (Cape Verde) make up more than half of the named tropical systems that annually form and account for more than 80-85% of all major hurricanes (Category 3 and above) that strike the United States and Caribbean islands.
The explanation is pretty simple -- warm Atlantic waters (Nino) create the environment for more spin ups in this area while the opposite La Nina phenomenon leads to more Caribbean and Gulf spin-ups. Here’s an explainer graphic below showing the Atlantic Nino provides warm SST (sea surface temperatures) enhancing rainfall (convection) and spin (RV). The opposite, La Nina, creates a friendly storm environment in the Caribbean and Gulf because winds are lighter (so storms don’t get torn apart) and water is plenty warm, so more spin-ups!
Given that this year we’ve already had Bret and Cindy that both started in the Cape Verde area, it makes perfect sense to study this region for increased tropical development and better forecasting. You can have a look at the full article from National Oceanic and Atmospheric Administration Atlantic Oceanographic and Meteorological Laboratory right here.
A few showers this week before back to hot!
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