The Atlantic hurricane season will be active or extremely active this year, according to a National Oceanic and Atmospheric Administration (NOAA) forecast.

There is a 70% likelihood of 13 to 20 named storms with winds of 63kmh or higher.

Of these, seven to 11 could become hurricanes (winds 119kmh or higher), including three to six major hurricanes (179kmh or higher).

Predictions for the six-month season starting on Saturday are above the average of 12 named storms, six hurricanes and three major hurricanes.

El Nino is not expected to develop and suppress hurricane formation, NOAA says.

The tropical Atlantic Ocean and Caribbean Sea will be warmer than average, while the atmospheric climate pattern that has prompted high hurricane activity since 1995 will continue, the US government agency predicts.

Meanwhile, NOAA says there is a 55% probability of a below-normal hurricane season in the eastern Pacific, with a 35% chance of a near-normal season and a 10% probability of an above-normal one.

There is a 70% chance of 11 to 16 named storms, including five to eight hurricanes, of which one to four are expected to become major hurricanes.

An average eastern Pacific hurricane season – from May 15 to November 30 – has 15 named storms, including eight hurricanes, four of which are major.

The forecast is based on a continuation of the climate pattern that has caused low activity since 1995.

NOAA also expects near or below-average sea surface temperatures in the eastern Pacific, with El Nino and La Nina unlikely.

“Although a below-normal season is most likely this year, we encourage everyone to get prepared for the start of the season and to check the forecast as storms develop,” NOAA forecaster Gerry Bell said.

“It only takes one storm making landfall in your area to make it a bad year for you, regardless of the overall activity predicted in the seasonal outlook.”

The report does not predict how many storms will hit land. NOAA says it has made improvements to its models and warnings for this season.