(01/11/2015 − 01/16/2015)
The STRAT_F has already peaked around 01/15/2015, which was very close to the range that we first forecasted on 12/4 (around 1/15-1/20).
The STRAT_G1, which is the second round of the subsequent events following the break-up of the polar vortex right at the New Year, has remained highly persistent and is still forecasted to occur between 01/21/15-01/25/15 as first forecasted on 12/17. This event remains capable of producing wintery storms over North America.
The new polar vortex has been rebuilding with the remnants of the previous vortex but has struggled to become very strong because of the occurrence of the STRAT_F and STRAT_G1 events. After G1, the new polar vortex is expected to get stronger graduatually. Thus we expect the STRAT_G2 to be on time. STRAT_G2 is still forecasted to occur within the first week of February and is the first weak STRAT event of the new polar vortex, which will bring in cold air into the mid-latitude region during the late half of the first week and the first half of the second week of February.
Forecasts Made on January 16, 2015
Follow up on Forecast Made in Previous Weeks:
·STRAT_G1, is still expected to take place between 01/21-01/25 and cause another round of sub-continental scale cold air surges. This event will still occur before the rebuilt of the polar vortex, resulting in a weaker impact across the mid-latitudes. Because of the below normal temperatures that are already existent across the mid-latitude region, we cannot rule out the possibility of wintery precipitation associated with this event, as that associated with STRAT_F.
·STRAT_G2, the first STRAT event of the newly rebuilt polar vortex, is still forecasted to peak around 02/02-02/06 as originally forecasted on 12/17. Because the polar vortex will be only newly rebuilt, the strength of this event is not expected to be overly strong.
·As first forecasted last week, STRAT_H is still expected to peak between 02/13-02/18 and cause a stronger continental scale cold event to occur. This event will bring below normal temperatures and wintery precipitation as well. It is most likely to impact a larger area of the mid-latitudes than the previous STRAT_F and STRAT_G events.
New Forecasts Made on January 16, 2015