The Great Southern Route : 2010 - 2011
WEATHER ROUTING 118 | GSR the northerly and easterly winds synonymous with the wintertime northeast monsoon. Again, winds are light, with speeds generally no more than force 3-4, but higher winds are common within squalls, particularly those associated with west to northwestward moving tropical cyclones. Combined seas are generally wind driven in nature, heights typically from 3-6 feet, though higher seas can occur in and near squalls. Further, long-period north to northeast sets will propagate southward into much of the region. These are often found in the wake of cold fronts passing north of the region, and will tend to be no more than 4-7 feet, tending lower the farther south one travels. During the winter, we are in the Northeast Monsoon season, with northerly and easterly winds dominant across the region. Winds average anywhere from force 3-5, though will tend lower in more southern latitudes, particularly within the southern South China Sea. Surges of higher winds will occur when ridging across much of Asia builds farther to the south and east, usually found after cold fronts pass near and north of the area. These surges will usually be about one to two Beaufort forces higher, especially in the central South China Sea. In addition, combined seas will build during wind surges, reaching as high as 10-12 feet in the central South China Sea, though becoming somewhat lower and longer-period farther south. Although tropical cyclone formation can occur in the western Pacific region during the winter, it is more uncommon during this time of year than during the rest of the year. Any cyclone development will mainly be found south of 10N, north of 06N. More organized systems (tropical cyclones) will generally track toward the west across the South China Sea, though systems farther north (in the central South China Sea), will at times turn northwest to northward, more so later in the period (in September), as cold fronts become stronger and higher south to southwest winds aloft allow for such "re-curvature" of tropical cyclones to occur. The tropics are still a factor during the fall, though we are moving into a transition period during this time, away from the southwest monsoon, with associated southerly/westerly winds becoming more intermittent and mixing with Taiwan Strait can develop much higher winds to this region, with winds often as high as gale and near gale force (force 7-8). Near the China coast and the Sea of Japan the pressure rises from August into September and the low over southern Asia fills. As the southwest monsoon disappears, winds shift back to northeasterly force 4-5. During the fall and into the winter months, winds are predominantly influenced by a building Siberian high, which encompasses Eastern China, the Yellow Sea, and the Sea of Japan vicinity. Winds are mainly from the north to northeast across Eastern Asia, becoming more north to northwesterly north of 45N. As the Siberian high strengthens, strong northerly surges become more common across the East China Sea and Taiwan Strait. During a strong surge, winds can reach gale force (force 8-9) and seas build through the strait and across South China Sea, as high as 10-15 feet within the strait itself. CENTRAL AND SOUTHERN SOUTH CHINA SEA: The weather across this region is marked by two distinct monsoon seasons. The southwest monsoon typically occurs during the period from May through September, with south to southwest winds dominant during the period. These winds for the most part are "light", generally of no more than force 3-4, with seas consisting of a wind chop of no more than 4-6 feet. Clusters of squalls moving westward across the area will create localized higher winds and seas, mainly confined to squalls themselves or areas very near squalls. Larger, more persistent squall areas can become better organized, particularly in the warmer waters and with a favorable "environment" aloft, typically in waters near and Figure 1: Typical weather patterns and tropical system tracks across the Western Pacific during the summer months.
2008 - 2009
2013 - 2014