BLOG: Above-average Hurricane Season forecast

BLOG: Above-average Hurricane Season forecast

CHARLOTTE, NC (WBTV) - Following an 11-year period where the United States was spared a single landfalling major (category 3-5) hurricane, 2017 brought three majors - Harvey, Irma and Maria - to our shores.

Those three storms all rank among the costliest in history. Though the Carolinas were spared from the worst, many are wondering now: what will the 2018 season bring?

The Atlantic basin hurricane season runs from June 1 through November 30, though most of the really intense storms (category 3 or higher which account for 90% of all damage) occur between mid-August and mid-October.

With the start of the season less than two months away, Dr. Phil Klotzbach of Colorado State University released his forecast Thursday at the National Tropical Weather Conference being held at South Padre Island, Texas.

Klotzbach called for a slightly above-average season ahead, with 14 name storms expected, seven of which he called for to become hurricanes, and three of those intensifying to major hurricane status.

While above the long-term (30 year) averages of 12 named storms, six hurricanes and three major hurricanes, this forecast is quieter than 2017, which had 17, 10 and six, respectively.

Of these storms, CSU predicts a 63% probability of at least one major hurricane making landfall on the continental United States. This number is above the average of 52%.

As for North Carolina, Klotzbach says there's a 36% chance for a hurricane impact this season and a 10% for a brush with a major hurricane, while the probability for South Carolina stands at 23% impact, 5% from a major storm.

A critical factor that went into making last season so active was the extremely warm water that developed in the Atlantic ocean basin. This near-record warmth contributed to the surge in activity in 2017, especially in terms of major hurricanes.

While the western tropical Atlantic is currently warmer than average, other portions, including the eastern tropical Atlantic and the north Atlantic, are cooler than average.

Klotzback said, "As of now, I don't see anything in the immediate future that would cause Atlantic sea surface temperatures to warm up dramatically.  However, there is certainly still time for this to occur, which is one of the biggest challenges with issuing forecasts this early."

An update to this forecast will be made May 31.

One factor forecasters will be monitoring closely is El Niño and La Niña. These are common meteorological terms that we hear about before seasonal hurricane forecasts are made because they play critical roles.

A strong El Niño or La Niña has a significant impact on hurricane development.

El Niño is a naturally occurring phenomenon, characterized by warmer than normal water in the eastern Pacific equatorial region near Peru. While El Niño occurs in the Pacific Ocean, it has widespread impacts on the global environment. The most notable element is increased wind shear across the tropical Atlantic, which creates hostile conditions for hurricane development (by blowing off / shearing the tops of developing storms).

La Niña is the opposite of El Niño and is characterized by cooler water in the eastern Pacific equatorial region. When La Niña is present, conditions tend to be more favorable for hurricane development in the Atlantic, which is what happened last season.

Currently, we are in a weak La Niña, but long-range forecasters believe there will be a transition to a neutral phase of El Niño over the next several months, making for a slightly better hurricane-growing environment.

If El Niño does develop, Klotzbach advises the forecast could be pared back, which would be good news for east coast residents.

As you know, however, over my many years at WBTV, I have always cautioned that if there is only one hurricane this coming season but it happens to strike your neighborhood, it will have been a busy season!

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