New Forecasts Made on October 8

 

STRAT_B1 (11/10-11/15)

We are forecasting a new event, named as STRAT_B1, to occur between 11/10 and 11/15. STRAT_B1 is a short event, sandwiched between STRAT_B and STRAT_C events. Since STRAT_B1 is right after STRAT_B, we expect a substantially large area over northern latitudes of North America and Eurasia to go back to the below-normal temperature regime in the end of the second week and first few days of the third week of November. 

 

Follow up on Forecast Made in Previous Week

 

STRAT_A (10/16-10/22), a week-long strong event of mass transport into the stratospheric polar region first forecasted on September 24 to occur between 10/21 and 10/28, is going to peak around 10/20, 2-3 days earlier than the last week’s forecasts. Accompanied with STRAT_A, surface air temperatures are going to drop significantly and rein the vast areas of North America except the west coast region in the mid-latitudes north of 30°N. Closely following the STRAT_A, in the period 10/22-10/26, below-normal temperatures are expected over large areas of Eurasian continent, mainly over the Siberian region of Asia and the Eastern Europe. The Halloween weekend is still expected to be warm, since it is going to be at the inception between STRAT_A and STRAT_B.

 

STRAT_B (11/01-11/06), a comparatively weak PULSE event, first officially forecasted on October 7, is still expected to occur in the first week of November, which will cause cold air surges over northern latitudes of North America and Eurasia.

 

STRAT_C (11/20-11/27) is first officially forecasted on October 7 to occur in the third week of November. We have revised the date range for the occurrence of STRAT_C in this week’s forecasts, which is expected to appear about 4 days later than the original forecasts. As we forecasted in the last week, STRAT_C is going to be a major and week-long event with back-to-back multiple PULSEs. Therefore, we expect STRAT_C will result in major cold air outbreaks over much of the area of mid-latitudes, particularly over North America. Therefore, STRAT_C will likely cause major interruption of Thanksgiving holiday travelers.