NHC: National Hurricane Center lowers 2017 outlook to 12 named storms, 7 hurricanes

The National Hurricane Center has issued its annual outlook for the upcoming tropical season, which runs from June 1 to November 30, and it is slightly less wacky than it was a year ago.

“The outlook calls for a seasonal average of 12 named storms, including seven hurricanes, three of which are major hurricanes (Category 3, 4 or 5),” the center said.

This year there is one thing that is different from the past few. Although the cycle of tropical storms that occurs each season varies slightly, there is an outside chance that El Niño will affect the Pacific Ocean with flooding rains, which usually plagues the Southeast United States with drought and floods.

Every 5 years there is a reading of the Atlantic System of Ionosphere (SOI), which scientists measure to tell the true strength of the jet stream.

“The period between 1973 and 2009 was the longest on record, when a total of seven seasons were cooler than normal and two were warmer than normal. The current eight season streak of warmer than normal seasons is tied for the fourth longest on record. In some ways, the beginning of the season may have put back a little something lost when the region saw an active season over the last two seasons,” the hurricane center said.

According to the National Oceanic and Atmospheric Administration, the average annual maximum wind speed of hurricanes is 78 mph, and the average maximum storm surge height is 13 feet above sea level, so an increase in strength means the swells from the storms may generate more floods and the storm surge could be more destructive.

“The outlook also is slightly warmer than normal, and during recent years, higher pressure systems have overspread the lower 48 states. When weather systems travel further and deeper into the ocean, there is usually an increase in season energy and related activity. However, it is too early to call for a stronger season due to the lack of significant seasonal effects from strengthening winds and associated stronger systems in the central and eastern tropical Atlantic. Several factors such as the behavior of the JCSD [Joint Typhoon Warning Center] troughs and La Niña still have to be incorporated,” the hurricane center said.

The forecast is influenced by a number of variables including the strength of El Niño and the value of the so-called Bermuda High in the eastern Pacific Ocean, which is a stable region of high pressure.

“Our forecast is at odds with other experts who expect a slightly stronger Atlantic hurricane season. However, we expect above-average activity along the East Coast due to a re-emergence of El Niño in the Pacific Ocean and continued emergence of the atmosphere above the Atlantic Ocean,” Gerry Bell, lead seasonal hurricane forecaster with NOAA’s Climate Prediction Center, said.

Click for more from the National Hurricane Center.

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