(NEXSTAR) – We’re in for a busy storm season, according to the latest forecast by the National Oceanic and Atmospheric Administration. In fact, meteorologists predict up to 20 named storms between now and the end of November.

Even though those storms have yet to form, we already know what they’ll be called if and when they do materialize.

The World Meteorological Organization already decided on a list of 21 names. When a tropical storm strengthens to wind speeds of 39 mph or higher, it gets a name from the list, starting in alphabetical order.

There are 26 letters in the alphabet but only 21 names were chosen, seeing as the letters Q, U, X, Y, and Z are all left off because they aren’t common enough to be easily understood in local languages spoken in North America, Central America and the Caribbean (areas all affected by hurricanes).

We’ve already seen three named storms this season: Alex, Bonnie and Colin. The next three named storms would be Danielle, Earl and Fiona.

If a tropical storm strengthens into a hurricane (winds stronger than 74 mph), it keeps the same name.

In the event that this year’s hurricane season exceeds expectations and produces more than 21 named storms, additional names will be pulled from a backup list agreed upon by the World Meteorological Organization. The WMO used to use Greek letters after the primary list was exhausted, but said it caused too much confusion and abandoned the system in 2021.

The list of names cycles through and repeats every six years. Storms deemed particularly destructive have their names retired from the list of possibilities and replaced by another name starting with the same letter.