Tag Archive for: El Nino

Forecasters Predict Very Active 2024 Hurricane Season in Gulf

In January, I published a post about a British firm, TropicalStormRisk.com, that predicted an extreme 2024 hurricane season. It’s still early in the year, so any forecasts have a higher-than-normal degree of uncertainty.

However, more and more forecasters and model runs are pointing to the alignment of several factors that increase hurricane/tropical activity. They include the rapid onset of La Niña, warmer than normal sea surface temperatures, lower-than-normal barometric pressures in the Gulf of Mexico and more.

La Niña Favors More Storms in Gulf

Very few tropical systems made landfall in the continental U.S. last year thanks to a strong El Niño, which tends to disrupt storms in this latitude.

However, the waning of El Niño and the rapid onset of La Niña decreases wind shear in the Atlantic. This lets more storms form and enter the Caribbean and Gulf as opposed to pushing them toward the mid-Atlantic or tearing them apart. And that supports an aggressive forecast for the 2024 Hurricane Season.

From Hurricane Info by Meteorologist Reuben Garcia. Tracks of Hurricanes during La Niña years. Video showed far fewer storms in Gulf during peak El Niño years.

Warmer-Than-Normal Sea Surface Temperatures

Warmer than normal sea surface temperatures in the Atlantic Basin also favor the formation of more hurricanes. Currently, temperatures are more typical of July than March.

Warmer water temps provide more fuel for storms and help them intensify more rapidly. This can lead to the formation of more major hurricanes and hurricanes that form closer to shore with little warning.

From Hurricane Info by Meteorologist Reuben Garcia. European Model suggest extremely high probability of warmer than normal sea surface temps going into the peak of hurricane season.
NOAA’s sea surface temperature anomaly chart for March 12, 2024, shows temps 2 to 4 degrees celsius above normal from Galveston to West Africa.

This may be related to the warmest winter on record – 5.4 degrees above average through February, according to NOAA.

Below Normal Barometric Pressures in Gulf and Caribbean

The European Model is also suggesting something not seen in recent years – below normal barometric pressures in the Gulf and Caribbean.

From Hurricane Info by Meteorologist Reuben Garcia. Long-range European Model run suggests low barometric pressures in Gulf during hurricane season.

Other Factors Consistently Suggest Above-Normal Season

According to Garcia, the European model is also suggesting above normal precipitation in the Gulf and Caribbean and 50% more hurricanes than usual and 70% more accumulated cyclonic energy than usual for the Atlantic. That’s more cyclonic energy than the European model has ever predicted! And it has a pretty good track record in that department.

Garcia also points out that the most recent long-range runs of North American models are largely consistent with the European model.

Many Forecasters Agree

For many of the same reasons:

Colorado State University and the National Hurricane Center won’t release their predictions for another month or two when uncertainty is reduced.

It’s important to note that all of these forecasts are Atlantic-basin wide and probabilistic. They predict the probable volume of activity in the hemisphere, not when or where specific storms will make landfall.

More news to follow as it becomes available.

Posted by Bob Rehak on 3/13/24

2388 Days since Hurricane Harvey

NWS Says La Niña Has Ended, Likely Impact on Weather

On March 9, 2023, the Climate Prediction Center of the National Weather Service (NWS) announced that La Niña conditions which persisted for 3-years have finally ended. But we are not shifting directly into El Niño. Instead, we’re entering a transitional phase. NWS expects neutral conditions to continue through the Northern Hemisphere into spring and early summer of 2023.

La Niña and El Niño represent opposite phases of what meteorologists call ENSO, the El Niño Southern Oscillation in the Pacific Ocean. They govern recurring climate patterns across the tropical Pacific and have a cascade of global side effects, says NWS.

The patterns shift back and forth irregularly every two to seven years. This past La Niña phase lasted three years, an unusually long time.

NWS predicts that ENSO-neutral conditions will continue through the spring. The weather service also predicts El Niño conditions to form during summer 2023 and persist through the fall.

Impacts on Weather

The oscillation brings predictable shifts in ocean surface and atmospheric temperatures. These shifts disrupt the wind and rainfall patterns across the tropics.

El Niño brings cooler, wetter conditions to the southern U.S. in winter months. It also brings stronger steering currents that can disrupt low-pressure systems coming off the coast of Africa that turn into hurricanes.

La Niña, on the other hand, usually means less disruption, more Atlantic storms, and deeper droughts in the southern U.S. But we’re finally putting the most recent La Niña behind us.

ENSO Influence on Atlantic and Pacific Hurricane Seasons

The continental United States and Caribbean Islands have a substantially decreased chance of experiencing a hurricane during El Niño and an increased chance of experiencing a hurricane during La Niña. These maps (by NOAA Climate.gov, based on originals by Gerry Bell) explain why.

Typical El Niño effects on Pacific and Atlantic seasonal hurricane activity.

Overall, El Niño contributes to more eastern and central Pacific hurricanes and fewer Atlantic hurricanes. Conversely, La Niña contributes to fewer eastern and central Pacific hurricanes and more Atlantic hurricanes – exactly the opposite.

Typical La Niña effects on Pacific and Atlantic seasonal hurricane activity.

Other Influences on Hurricane Formation: AMO

NOAA also says that other oscillations, such as the Atlantic Multi-Decadal Oscillation (AMO) also influence hurricane formation. The warm phase of the AMO is associated with warmer sea surface temperatures and high hurricane activity in the main development region of the Atlantic between Western Africa and the Caribbean.

“The hurricane activity in any given season often reflects a combination of the multi-decadal signals and ENSO,” says NOAA.

For More Information

For a fuller discussion of how El Niño and La Niña influence other aspects of weather worldwide, check out NOAA’s Climate.gov, especially the FAQ page.

Also, the Associated Press ran an interesting story this morning by Seth Borenstein. The headline: “La Nina, which worsens hurricanes and drought, is gone.”

Borenstein says NOAA gives El Niño a 60% chance of returning this fall. But there’s also a 5% chance that La Niña will return for an unprecedented fourth winter.

We should have more certainty in a few months.

Posted by Bob Rehak on 3/9/23

2018 Days since Hurricane Harvey