El Niño forms over Pacific Ocean; will affect Southwest Florida later in year

According to scientists at the National Oceanic and Atmospheric Administration’s Weather Prediction Center, El Niño has developed across areas of the equatorial Pacific Ocean.

In the outlook that was released on June 8, forecasters issued an El Niño advisory, highlighting that El Niño conditions were present and expected to increase into the winter months.

El Niño is a naturally occurring weather phenomenon of warmer-than-average sea surface temperatures (SSTs) in the equatorial Pacific Ocean that typically happen every two to seven years.

In Southwest Florida, El Niño’s impacts are largely felt more in the wintertime months than in the summer. By winter, forecasters are expecting there is an 84% chance of a greater-than-average strength El Nino and a 56% chance of a strong one.

On average, a strong El Niño produces wetter and slightly cooler winters across the state.

El Niño also helps suppress tropical development in the Atlantic due to higher wind shear aloft. Wind shear is increasing wind speeds with height, effectively “shearing” off the tops of storms, or hindering their chance of development altogether.

However, with the warmer-than-average SSTs in the Pacific and increased wind shear expected across the Atlantic, there is also something else worth noting. The waters across portions of the Atlantic are well above average for this time of year as well.

There is a large area that forecasters observe called the main development region. This region covers areas just north of the equator in the central Atlantic, expanding from the west coast of Africa, and extending into the Caribbean.

This MDR has observed record high temperatures for the month of June across this region and may counteract the higher wind shear expected from the strengthening El Niño.

Warm SSTs are a key ingredient in fueling tropical systems. The record warmth of the Atlantic may be a precursor to a tug-of-war between El Niño (and the expected decrease of tropical systems) and the warm waters of the MDR that may potentially increase the chances for tropical systems to form.

One of the biggest culprits in driving the astonishing warming of the Atlantic SSTs is the lack of the Azores’ high pressure. The much weaker and displaced high pressure reduces the trade winds over the tropical Atlantic and northern Africa, which in turn reduces the evaporational cooling of the water and it reduces the transport of Saharan dust across the eastern tropical Atlantic.

If this trend continues, then the Atlantic SSTs may be an excellent source of fuel to help develop tropical systems.

For now, it will be a waiting game to see how warm the Atlantic remains and just how strong of an El Niño will develop over the coming months.