(12/12/2014 − 12/17/2014)
· Our STRAT_D1 event, forecasted to peak between the period of December 18 -24 (first forecasted on 11/25), is expected to have two peaks: 12/18 and 12/21. STRAT_D1 event is bringing cold air to East Asia in next few days and is expected to bring storm activities in North America in the next few days before Christmas, as shown in the short-range NWP forecasts. So our forecasts for STRAT_D1 are successful. However, the intensity of STRAT_D1 is expected to be weaker than previously forecasted (in the order of 500 billion tons per day instead of 700+ billion tons per day). Therefore, these winter storms are not as strong as we thought in the previous forecasts. The STRAT_D1 event will impact pre-holiday travel, particularly for travelers over North America.
· STRAT_E, which we first forecasted on November 20 to occur in the week around New Year (forecast lead time: 40 days), is now looking to be stronger than STRAT_D1. We have upgraded the severity of the cold air outbreaks associated with STRAT_E, but we still expect this round of cold air outbreaks to occur within the week surrounding New Year. This event poses a big threat to affect post-holiday travel, particularly travelers over North America where a major cold air outbreak is expected to cross the continent within few days around New Year.
· STRAT_F event remains quite consistent on its way to deliver approximately 800 billion tons per day at its peak time to the polar stratosphere in the period of January 15-20, as we first forecasted on Dec. 5 (forecast lead time: 40 days). Again both continents have high probability to suffer from another round of major cold air outbreaks.
· This week, we officially forecast a new event, STRAT_G, to take place in the last week in January and into the first week of February. We will narrow down the date range of this new event as our forecast lead time is close to 30-40 day range. Also the intensity of its associated cold air outbreaks is looking to be quite strong, but we will continue to monitor the strength of this system.
Forecasts Made on December 17, 2014
Follow up on Forecast Made in Previous Weeks:
· STRAT_D1 event will take place on time as first forecasted on Nov. 25. Although its intensity has been downgraded, STRAT_D1 is expected to produce wintery precipitation to impact pre-holiday travel in certain regions over both continents, but mainly over North America.
· STRAT_E will take place on time as first forecasted on November 20. We have upgraded STRAT_E, which is expected to be stronger than STRAT_D1. STRAT E will produce cold temperature events in the week around New Year, and still has a possibility to impact post-holiday travel, particularly for travelers over North America where a major cold air outbreak is expected to cross the continent within few days range around New Year.
· No Changes in forecasts for STRAT_F. (first forecasted on December 4). STRAT_F will cause the first round of major cold air outbreaks in 2015 over the two continents. STRAT_F event will be a strong event with peak intensity of exceeding 800 billion tons per day.
New Forecasts Made on December 17, 2014
· We are officially calling for STRAT_G to occur within the last of January and into the first week of February. We will continue to monitor the strength of this round of cold-air waves and provide a more narrow range for this event in the next week forecasts.