Atlantic Tropical Outlook 2017

Most recent tropical cyclone forecasts from each of the forecasting centers.


Hurricane forecasts for the upcoming tropical season in the Atlantic have been published. The average of the statistical/dynamical models are pointing to a neutral ENSO to very slight warm event heading into the main part of the Atlantic tropical season (Aug-Oct). Latest forecast probabilities from IRI show a 60% chance of El Nino developing and a 35% chance of a neutral season. The latest NOAA forecast puts the chances of El Nino development at 50%. Most forecasts point towards an ENSO neutral phase that will not have too much influence on the Atlantic season.

Most predictions for this season are forecasting activity to be around normal to a little above normal. The NOAA forecast is calling for a 45% chance of above average tropical cyclone activity over the Atlantic basin while the April-issued Colorado State University forecast is forecasting normal activity. If we look at the aggregate or consensus of the forecasts, we find an average of 12-13 named systems, 5-6 hurricanes and 2-3 major hurricanes, giving us average to slightly above average activity for the 2017 tropical season.

While we cannot point to exact hurricane formation dates and tracks weeks to month in advance, there are studies on general expected impacts depending on the phase of ENSO. The warm phase of El Nino has the lowest probability of hurricane landfall along the Gulf, Florida and east coasts. The cold phase of ENSO, or La Nina, produces the highest chance of landfalling hurricanes alone the east coast. Neutral and warm phases see this chance decrease by approximately 40%. Neutral ENSO events lead to higher chances of landfalling hurricanes for Florida and along the Gulf coast, especially for storms that form to the west of 50⁰W.