Tuesday, November 24, 2020

El Niño/Southern Oscillation: Decisive Shift From La Niña To ENSO Neutral By 2021 North Atlantic Hurricane Season

 Meaning that insurers/reinsurers putting through premium increases based on 2020 may be looking at superior underwriting profitability next year.

Of course there are a myriad of other factors, and one that bears watching is the tendency over the last two years of tropical cyclones to intensify as they approach landfall.

For a first pass look at what we might see in 2021 here's Columbia University/IRI's chart of the various models:

IRI ENSO Forecast
IRI/CPC ENSO Predictions Plume
Published: November 19, 2020
Note on interpreting model forecasts

The following graph and table show forecasts made by dynamical and statistical models for SST in the Nino 3.4 region for nine overlapping 3-month periods. Note that the expected skills of the models, based on historical performance, are not equal to one another. The skills also generally decrease as the lead time increases. Thirdly, forecasts made at some times of the year generally have higher skill than forecasts made at other times of the year--namely, they are better when made between June and December than when they are made between February and May. Differences among the forecasts of the models reflect both differences in model design, and actual uncertainty in the forecast of the possible future SST scenario.....MUCH MORE