Backward Trajectory Map in June 2012

By using computer model analyses, the past 72-hour backward trajectory of the air mass reaching Hong Kong is estimated by the Observatory on a daily basis. The daily trajectories are compiled into the Monthly Backward Trajectory Map. The Monthly Map for June 2012 is now available on the following webpage:

http://www.weather.gov.hk/en/wxinfo/trajectory/trajectoryMonthly.shtml

According to the backward trajectory map below, the air masses reaching Hong Kong in the first half of June 2012 mostly originated from the northeast, indicating the predominance of ridge of high pressure over the coastal areas of eastern China. The air masses reaching Hong Kong in the second half of the month originated from the southwest, indicating the influence of the southwest monsoon over the territory.

Backward Trajectory of Air Mass reaching Hong Kong in June 2012

For Daily or Seasonal Backward Trajectory Maps, please visit the following webpages:

Daily Backward Trajectory Map
http://www.weather.gov.hk/en/wxinfo/trajectory/trajectory.shtml

Seasonal Backward Trajectory Map
http://www.weather.gov.hk/en/wxinfo/trajectory/trajectorySeasonal.shtml