This question will resolve as Yes if, before 2029, the European Centre for Medium-Range Weather Forecasts (ECMWF) reports that the day 10 forecast for 500 hPa height has reached an anomaly correlation coefficient of 60% or greater for either the Northern Hemisphere or Southern Hemisphere, using the 12-month running mean.

Fine Print

Reaching the 60% threshold at any point and for any length of time is sufficient.

If numerical data is not available, Metaculus will use their discretion to determine if the plotted line for either hemisphere has touched or surpassed the 60% grid line.

The question will resolve as No if the criteria have not been met according to the information shown on the chart on January 1, 2029, regardless of any data lag. In the event ECMWF stops publishing this data Metaculus may select an approximately equivalent source or resolve the question as N/A.