Winter '09 / '10 - NAO Forecast - MET Office

The UKMET Office...the British version of the US NWS...produces a statistical NAO forecast (reg. reqd.) for the upcoming winter.

The forecast for 500 mb heights is based on an analysis of observed and the 'predictor pattern' of SST anomalies in the northern Atlantic Ocean during the month of May.

"By taking the observed SST anomaly for May (figure at left) and calculating how it projects onto the predictor pattern we can make a prediction for the winter NAO. If the projection is positive (i.e. the anomaly pattern looks similar to the predictor pattern shown below) then the prediction is for a positive winter NAO. Conversely, if the observed May SST anomaly projects negatively onto the predictor pattern (i.e. it looks like the reverse of the predictor pattern) then we would predict a negative NAO."



There's a weakly negative statistical correlation between season-total snowfall in New England and the Mid-Atlantic regions and the NAO. This association is often mis-applied to individual storm systems -- if we could just get the NAO to turn negative...then we're more likely to get snow.

NAO forecast was quite good last year. Snow crows hope it's not as advertised this winter.