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2007.10.01
The Southern Hemisphere winter of 2007
The Southern Hemisphere winter of 2007 was marked by a number of significant weather events: 11m swells were reported to hit Reunion Island in late May; ‘huge’ waves were reported to hit the Maldives in late May; the MV Pasha Bulker ran aground at Newcastle, Australia, after 70 knot winds developed across the Tasman Sea in early June; as many as ten vessels were sheltered along the South African coast as very heavy conditions battered the coast in late July. These significant events, as well as a few others, indicate that the winter of 2007 was particularly bad for ships at sea in the Southern Hemisphere.
Figure. Sea Level Pressure (mb) composite anomaly for June _ August 2007, as compared to climatogical mean 1968-1996. From NCAR/NCEP global Reanalysis Data provided by Earth System Research Labratory.
Figure shows mean sea level pressure anomaly for June, July and August _ the heart of the winter season in the Southern Hemisphere. This graph indicates that sea level pressures were lower than average across much of the South Atlantic and South Indian oceans, south of South Africa, and in the Tasman Sea. While some ships do sail through the South Pacific and around Cape Horn, the majority of shipping traffic in the Southern Hemisphere is through the South Atlantic, around the Cape of Good Hope, and through the South Indian Ocean. Therefore, the low pressure anomalies across the South Atlantic, south of South Africa and through the South Indian Ocean are of particular importance.
The synoptic pattern across the Southern Hemisphere this past winter set up such that the major shipping lanes across the South Atlantic, South Indian and around the Cape of Good Hope experienced heavier than average weather conditions. The main low track was shifted northward, allowing more and stronger lows to track through the main shipping lanes of these basins. This also caused significant swell conditions to track further north through these basins. It was a challenging season for routeing ships, particularly around the Cape of Good Hope.
