Summer outlook: How a flip to La Niña could stir the Gulf, affect Central Texas

AUSTIN (KXAN) -- While June 1 marks the beginning of meteorological summer, it also signifies the start of Atlantic Hurricane Season. A number of factors suggest that we could be in for a very busy few months ahead in the tropical Atlantic.

El Niño out, La Niña soon to take over

Although a winter El Niño brought wetter-than-normal conditions to much of Central Texas, it didn't bring enough rain to the Hill Country. Now El Niño is in the process of wrapping up quickly as part of the El Niño-Southern Oscillation cycle, or ENSO. As the sea surface temperatures in the eastern equatorial Pacific Ocean start to cool, we're entering a period known as ENSO Neutral where those water temperatures don't influence our North American climate pattern. Once those waters cool more than half a degree centigrade below normal, then we enter the "cool phase" of ENSO, known as La Niña.

While you may know La Niña for its warmer and drier pattern during our winter months, La Niña also has a notable impact on Atlantic Hurricane season.

When La Niña happens during hurricane season, there's usually weaker vertical wind shear in the Atlantic Ocean. This means the atmosphere over the Atlantic is more conducive to the development of hurricanes and tropical storms because they aren't being ripped apart by wind.

At the same time, we're looking at incredibly warm sea-surface temperature anomalies in the Main Development Region, or MDR, of the Atlantic, which is the area many of our more prolific and longer-lasting tropical systems develop.

The combination of very warm waters that help hurricanes grow, plus the lack of wind shear that could tear them apart, means all signs are pointing to a very active Atlantic Hurricane season.

NOAA's Atlantic Hurricane Season Forecast

On Thursday, NOAA released its initial hurricane forecast for the Atlantic Hurricane Season, which begins June 1 and lasts through the end of November. The forecast shows an aggressively busy season with more named storms, hurricanes and major hurricanes compared to a normal year.

Back in April, Colorado State University released its hurricane outlook which also called for an incredibly busy season.

There is a lot of scientific consensus that this Atlantic Hurricane Season could be hyperactive.

All eyes on the Gulf

One of the key challenges with hurricane forecasts is messaging. A "quiet" season wouldn't be perceived as quiet if one major hurricane made a direct landfall in a densely populated area. The phrase "all it takes is one storm" is commonly used during tropical forecasting. Similarly, an "active" hurricane season could be remembered differently if most of the named storms stayed out to sea.

One conclusion can be drawn from the forecast for an active Atlantic hurricane season: If there are more named storms, the chances are higher that some of those storms may enter the Gulf of Mexico.

"We haven't been hit by a hurricane in Texas for a while," KXAN meteorologist Rich Segal noted. "The last one was in September of 2021 when Hurricane Nicolas hit at Matagorda Peninsula with winds of 75 miles per hour. Last year, we did have a tropical storm hit the southern part of the state around Padre Island. The winds there were tropical storm, like less than 75 miles per hour, and that was Tropical Storm Harold."

Of course, back in 2017, Hurricane Harvey caused incredible destruction and tremendous rainfall rates.

"The one that everybody remembers is Harvey, you know, dropping more than 50 -- up to 60 inches of rain ... in the Houston area up into the Beaumont Port Arthur area, but it hasn't come to pass in 2023," Segal said, adding "you would say that maybe we are due."

Of course, Gulf-based tropical systems could also provide Central Texas with some beneficial rain. Ideally, a tropical storm tracking toward the Hill Country would be our best hope for that.

Inland flooding from excessive rainfall remains our greatest threat from landfalling hurricanes.