The AER winter forecast, which has been offered since 2000, is informed by the landmark Snow Area Index (SAI). (aer.com)
Mention of the «secret» cold winter forecast appears in the Quarmby Report (Section 2.4) which states, «The Met Office gave «early indications of the onset of a cold spell from late November» at the end of October.» (co2insanity.com)
Improved Winter Forecasts Using a New Snow Index. (aer.com)