What we do: We are making sub-seasonal forecasts for time periods of high probability of cold air outbreaks in Eurasia and North America 30-40 days in advance. We issue such forecasts on a weekly basis and this website is updated around Thursday each week.
New Feature: Maps of probability of cold surface temperature anomalies over both North America and Eurasia continents in the vicinity of forecasted stratospheric PULSE events
New Forecast Made on March 10:
STRAT_J (03/24 – 03/28)
This week we are forecasting a new stratospheric PULSE event, named as STRAT_J, to occur between 03/24 and 03/28. STRAT_J looks to be a moderate event with peak net air mass transport into the polar stratosphere about 0.8 trillion tons per day. Associated with STRAT_J is going to be a new round of cold air incursions over the two continents. Based on our map forecasts, The majority of Eurasia continent will suffer a new round of cold air outbreak first and then cold anomalies will dominate over the Southwestern half of North America continents. Up to 50% area in North America will suffer below normal temperature. However, due to the recent back to back stratospheric sudden warming events, the polar vortex has been weakened significantly, therefore we believe this event could be the last major stratospheric PULSE event before the final breakup of the 2016-17 polar vortex.
Follow up on Forecast Made in the Previous Weeks:
STRAT_I (03/08 – 03/12), first forecasted on 02/11, is expected to take place on time with a peak around 03/12. As we forecasted, STRAT_I is a moderate “aftermath” event after the major stratospheric sudden warming event, with a peak intensity of 0.6 – 0.7 trillion tons per day. Associated with STRAT_I, the majority of the area above 45°N in both North American and Eurasian continents will experience below-normal temperatures and wintery precipitations.
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