MIAMI (AP) — U.S. forecasters predicted Thursday that this year’s Atlantic hurricane season would produce a normal number of about nine to 15 tropical storms, with as many as four to eight of those becoming hurricanes.

The National Oceanic and Atmospheric Administration released its initial outlook for the six-month storm season that officially begins June 1. One to three storms could become major hurricanes with top winds of 111 mph or higher.

Though this season isn’t expected to be as busy as last year’s above-average season, federal officials warned coastal residents to start stocking up on hurricane supplies and forming evacuation plans anyway.

“That’s still a lot of activity. So just because we’re predicting a near normal season doesn’t mean anybody’s off the hook at all,” said Gerry Bell, the lead seasonal forecaster at NOAA’s Climate Prediction Center.

Atmospheric and marine conditions indicating a high-activity era that began in 1995 for Atlantic hurricanes continue, Bell said.

However, the weather phenomenon known as El Nino, which warms Pacific waters near the equator and increases wind shear over the Atlantic, may develop by the late summer or early fall and help suppress storm development.

“Our range (of expected storms) is a bit wider this year because of this inherent uncertainty right now based on the best guidance we have as to whether El Nino will form or not,” Bell said.