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.
The 2016-2017 Forecast Season has begun!
New Forecast Made on November 20:
STRAT_D (12/17 – 12/21)
We are forecasting a new event, named as STRAT_D, this week. STRAT_D is expected to occur between 12/17 to 12/21. STRAT_D looks to be a moderate event with a peak net mass transport into the polar stratosphere about 0.9 trillion tons per day. We expect modest cold air incursions over the North American continent. Associated with STRAT_D, the Eurasian continent may also suffer from cold air incursions, although not as severely as those over North America.
We continue to forecast mild winter conditions over both continents in the 2-3 weeks after STRAT_C is over till STRAT_D when the new round of cold air outbreaks begins.
Follow up on Forecast Made in the Previous Weeks:
STRAT_B2 (11/15 – 11/21), which is forecasted on 10/21, is happening right now. STRAT_B2 peaked on 11/12 and 11/16, transported over 0.8 trillion-ton each day. It mainly affects mid-latitude regions in the North America where regions along Rocky Mountains are getting first snow this year, and we expect about 60% of the area will report below-normal temperatures in the next few days.
STRAT_C (11/25 – 11/30), first forecasted on 10/14 at a lead time of 40 days, is still going to take place in the period 11/25 to 11/30, with the main peak around 11/26. STRAT_C looks to be a modest event transporting about 1 trillion-ton air mass per day into the polar region at its peak time. It will greatly affect mid-latitudes of both continents.
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