(02/13/2015 − 02/18/2015)
STRAT_H delivered two of the three peaks so far that were within the range of 02/13-02/18 as we first forecasted on 01/10/2015. The second peak was accompanied with a net of 12-14 trillion tons per day of cold air discharge into mid-latitudes at the peak times (02/14 and 02/17), ranked as the third strongest cold air discharge event, resulting in up to 75% area of North America occupied by below-normal temperatures. The third peak of STRAT_H is going to take place tomorrow and its associated cold air discharge is going to peak around 02/21. The third peak of STRAT_H will keep the North American continent experiencing below normal temperatures, and will mainly impact Eurasia such that its percentage area suffering below-normal temperatures will increase from 30% to 50%.
STRAT_I is still expected to peak between 02/27 and 03/04 as we first forecasted on 01/29. This event is expected not as strong as STRAT_H. Nevertheless, this event would cause cold air surges in both Eurasia and North America. The cold conditions may well extend to the first week of March.
Last week we officially called for STRAT_J to occur between 3/12- 3/17. STRAT_J is a weak STRAT event, but it is still expected to bring in another round of cold air surge.
This week, we are forecasting a new event, STRAT_K, to occur in the last week of March. This event seems to be as strong as STRAT_E event, which caused break-up of the stratospheric polar vortex around the New Year. Therefore, we expect that STRAT_K event would cause major cold air outbreaks, particularly over North America. As a result, a large portion of North America will report below-normal temperatures between the last few days of March and the first week of April.
Because there will be only one minor event from the beginning of March to the last week of March, we expect March of 2015 is going to be mild.
Forecasts Made on February 18, 2015
Follow up on Forecast Made in Previous Weeks:
· STRAT_H will deliver its last and final peak towards the end of this week. Therefore the mid-latitudes will continue to experience wintery precipitation and rapid dropping of temperatures till around 02/22.
· STRAT_I is expected to deliver another round of cold air discharge between 02/26-03/04, as we originally forecasted on 01/29. This event will impact both Eurasia and North America.
· STRAT_J has remained on schedule and is still expected to occur in the time period of 3/12-3/17. STRAT_J seems to be a weak event although it is still capable of causing rapid drop of temperatures.
New Forecasts Made on February 12, 2015
This week, we forecast STRAT_K to occur in the last week of March. This event will be a strong event, which could lead to the second break-up of the stratospheric polar vortex for this winter season. The cold air outbreaks associated with STRAT_K would be severe and impact North America greatly. As a result, a large portion of North American will report below-normal temperatures between the last few days of March and the first week of April.