Next blocks created from weekly predicting maps of temperature, precipitation and air pressure anomalies for Europe, North America and World represent possible scenarios of behaving of circulation during next 6 weeks – until 18. January 2021 from source /https://www.ecmwf.int/en/forecasts/charts/.
Graphs below are 7-months forecasts of NAO index and PNA index.
NAO index forecast for January and February shows, that January 2021, with forecasted neutral NAO index, should have better conditions for coldwaves in Europe such as February with very high NAO index (NAO+).
On the other hand, eastern coast of the USA and Canada should be very warm during all period, thanks to NAO, but too negative low pressure anomalies above the continent.
Chances for return of winter conditions after possible NAO+ phase between cca 25. December – 15. January should be associated with signs of colder conditions above western parts of continents during last week (11.-18. January) – this anomaly should spread above continents during last January 2021 decade, maybe, with possible short NAO- / AO- phase with peak of Winter 2020/2021, before possible early spring conditions in February 2021 (belt of “colder” anomalies above subtropics in last week of forecast and close stocks of Arctic air near Europe / USA, development of conditions and long term forecasts…)
Cold and snowy Canada and warm and dry USA will be result of a La nina, PNA- will be cooling West coast.
Trio La nina / PNA- / NAO and AO+ is during winter months relatively common, such as El nino / PNA+ / NAO and AO- in most cases of winters.
In Australia and south-monsoon Asia, La nina will be bringing severe rain and storms during all period until 18. January 2021.
Western coast of South America will be with colder and dry La nina conditions, but Brazil and Caribbean will move gradually into more stormy regime as is usual (too typical for La nina).
Arctic Amplification (high pressure and temperatures) over the Arctic and low pressure above Africa are traditionally a result of climate change.
Infographics: ECMWF – temperature, precipitation and air pressure anomalies in Europe, Northern America and World during 6 weeks between Monday 7. December 2020 – Monday 18. January 2021
