TSR raises hurricane forecast slightly on potential for more favourable sub-tropical conditions

Tropical Storm Risk (TSR) has raised its forecast for the 2026 Atlantic hurricane season slightly, now calling for one more hurricane and major hurricane to form, citing “indications that the sub-tropical Atlantic may provide more favourable conditions for tropical cyclones.”

At its April forecast update, Tropical Storm Risk (TSR) had lowered its previous long-range forecast to call for 12 named tropical storms, 5 hurricanes and just 1 major hurricane for the 2026 Atlantic hurricane season, with expected accumulated cyclone energy (ACE) of 66.

Then in a May 28th update, TSR reduced its forecast numbers again, now predicting 11 named storms, 4 hurricanes and 1 major hurricanes, with ACE of 55.

But now, the latest forecast update from TSR is calling for still 11 named tropical storms, but with 5 becoming hurricanes and 2 becoming major hurricanes, while its forecast for the ACE Index has been raised slightly to 67.

What does this tell us?

Still, TSR’s forecast is for the 2026 Atlantic hurricane season to see activity levels that are around 40% below the 1991-2020 30-year norm, which is relatively unchanged it seems.

But the update and raising of hurricane numbers shows the meteorological environment continues to evolve under El Nino and that hurricane risk is not absent, just because forecast numbers are lower this year.

TSR said there is, “Only a 5% probability the ACE index will be in the upper tercile (>156), a 38% likelihood the ACE index will be in the middle tercile (75-156), and a 57% chance the ACE index will be in the lower tercile (<75).”

Adding, “The primary factor which has influenced the TSR North Atlantic April forecast to be around 40% below the 1991-2020 climatology is the developing strong El Niño conditions, which are expected to strengthen and persist through summer and autumn 2026. The reason for raising the forecast is because there are indications that the sub-tropical Atlantic may provide more favourable conditions for tropical cyclones, which may slightly offset the largely unfavourable conditions anticipated across the tropical Atlantic and Caribbean Sea.”

TSR’s forecast for US landfalling tropical storms for the 2026 hurricane season still remain unchanged, at 1 hurricane and 3 tropical storms to hit the coastline, below the 30-year norm of 1.6 and 3.8 respectively.

TSR also said that it forecasts August to September sea surface temperatures in the Atlantic Main Development Region will be slightly warmer than average, but that El Niño is expected to trigger stronger than normal Caribbean trade winds, which can increase wind shear.

However, the sub-tropical Atlantic is expected to have more favourable conditions, with higher sea surface temperature anomalies, above-average precipitation and lower vertical wind shear, which is why the forecast numbers were increased slightly, TSR explained.

As we always state, it takes just one major storm that makes landfall in a region with high economic and insured values can drive significant impacts to the insurance, reinsurance, catastrophe bond and insurance-linked securities (ILS) markets.

A forecast for lower storm numbers does not mean a greatly reduced chance of damaging hurricane events occurring, but likewise a slight increase does not immediately signal impactful events are ahead. The development of the season will need to be followed and risk is never absent, no matter how the forecast numbers are adjusted.

TSR’s update makes no difference to the average across all seasonal hurricane forecasts we’ve seen so far, being still 12 named storms, 5 hurricanes and 2 major hurricanes for the 2026 season in the Atlantic basin, still below the longer-term and recent historical seasonal averages. The average for ACE for the season has risen by 3 to 76.

Read some articles on the value of seasonal hurricane forecasts:

– Cat bond portfolio construction more important than seasonal hurricane forecasts: Man Group.

– ILS investment outcomes about more than just hurricane season forecasts: Gibson, Schroders Capital.

– Adjusting ILS exposure for July hurricane forecast can deliver excess returns: Euler, TSR study.