After two years of above-average activity, the 2019 hurricane season is here and meteorologists are predicting it will be less active this year.
The National Oceanic and Atmospheric Administration (NOAA) is predicting a "near-normal" Atlantic hurricane season this year, with a 40% chance of that happening.
For 2019, NOAA predicts a likely range of nine to 15 named storms (winds of 39 mph or higher), of which four to eight could become hurricanes (winds of 74 mph or higher), including two to four major hurricanes (category 3, 4 or 5, with winds of 111 mph or higher).
The hurricane season officially runs from June 1 to Nov. 30.
The outlook takes into account competing climate factors. NOAA forecasters say El Nino is expected to persist and "suppress the intensity of hurricane season." On the other hand, warmer-than-average temperatures on the surface in the tropical Atlantic Ocean and Caribbean Sea, as well as a west African monsoon, favor increased hurricane activity.
Colorado State University's Tropical Meteorology Project also released its 2019 forecast for the Atlantic hurricane season, which falls in line with NOAA. Their forecast calls for 13 named storms and five hurricanes, two of which will be in the "major" range.
Although both hurricane forecasts point to an average season, "normal" is far from safe. As UPI points out, last year was considered a relatively normal hurricane season and it included Hurricane Michael. Michael landed on the Florida Panhandle as a Category 5 storm, causing about $25 billion in damage and killing dozens of people.
How do they make their predictions?
The meteorologists behind the forecast rely on a variety of factors when making their predictions, but the two primary ones are the sea surface temperatures of the North Atlantic and whether or not El Nino develops in the Pacific Ocean.
El Nino brings with it warm sea surface temperatures in the Pacific, and that leads to stronger winds in the mid-levels of the atmosphere. These stronger winds limit the formation and strength of tropical storms in the Atlantic. El Nina is the reverse of that.
According to a May 2018 study, the magnitude of rapid intensification — when a hurricane intensifies by 25 knots or higher in a 24 hour period — has increased over the past 30 years. Major hurricanes today are traveling 13 mph faster on average, and researchers say a lot of that has to do with Atlantic Multidecadal Oscillation (long periods of times when sea surface temperature changes).
Editor's note: This article has been updated since it was originally published in April 2018.