The Great Southern Route : 2013 - 2014
GSR|63 into the northern Baja Peninsula, occuring about every three to four days. Later in the spring and during the summer/ early autumn (May through October), the thermal trough tends to be stronger, with troughing extending as far north as interior/ coastal California and Oregon. Weakening and a southward suppression of the trough will occur as smaller, weaker areas of high pressure "break away" from the nearly stationary high pressure ridge in the tropical/subtropical Pacific and into the northwest U.S. Weakening will also occur, as weakening cold fronts move southeastward into the western U.S., more likely to occur later in the period (in October), as cold fronts become somewhat stronger upon arrival along the U.S. West Coast. Farther west, a semi-stationary high pressure dominates across the tropical and subtropical Pacific, found mainly across waters between 40N and 10N and west of 110W. Slight flutuations in coverage and strength are likely to occur over a given time period. The ridge will tend to be weakest during the winter season (December through February), as larger, more intense gales and storms track slightly farther south from their summertime positions, but still well north of the region. However, transitory high pressure ridges moving into the Western Pacific will eventually merge with and "reinforce" the semi-stationary ridge, inducing surges of higher N-NE-E winds and larger N-NE-E swells across this region as well. The ridge will tend strongest during the summer months, as gales/storms in the North Pacific track further north. Looking south of 10N, the aforementioned ridge will interact with a broad east to west oriented trough of low pressure (equatorial trough), which on average covers the Pacific between 10S and 10N. During the late spring and summer months (May through August), the northern extent of the trough will normally be found closer to 10N, drifting southward later in the year, and reaching its southernmost location (near 05N) during December/January. With regards to tropical activity, cooler waters temperatures west of the Baja Peninsula, in particular those associated with the California Current (off the Baja Peninsula), will normally induce a weakening of tropical cyclones as they move farther west into this region. However, warmer water temperatures and lighter winds aloft can and do allow for tropical cyclone development during the summer months in more southern waters, mainly south of 20N. Such cyclones that form in this region will in the vast majority of cases track westward, weakening and/ or passing south of the Hawaiian Islands. NW-N-NE winds dominate across waters between the Baja Peninsula and approximately 115W-120W, generally "moderate" to "fresh" in intensity. However, surges of higher winds will occur, mainly during the late autumn, winter, and spring months, as surges of cooler air move in behind cold fronts. Large NW-N-NE swells will accompany wind surges, often near and in excess of 10 feet, though will tend somewhat lower and longer-period in more southern waters. Easing of winds and an abatement of seas will occur as ridging further west weakens, and as cold fronts approach the region from the north and west. EASTERN AND CENTRAL NORTH PACIFIC, EAST OF THE INTERNATIONAL DATELINE TO 110W Two weather features are prevalent throughout the year across more northern waters (north of 10N): high pressure to the west and a thermal trough (low pressure) farther east. The thermal trough is normally found across the Sea of Cortez, Gulf of California, and the Baja Peninsula. The trough will tend to be weaker and cover a smaller area during the mid to late autumn months (November/December), during winter, and in early spring. This is due to the presence of cold fronts moving southeastward into and across much of the western U.S. and (during the winter) offers a greater possibility of delays and/or stoppages due to adverse weather, particularly in NW-NE-E wind surges farther south (south of the Mexican Riviera), and NW-N wind surges farther north (across the Sea of Cortez and the Baja Peninsula). Routing options during the winter season become more limited as well. The best routing would be to maintain coastal routes. Taking coastal routing reduces the likelihood of encountering large seas associated with wind surges, especially farther south and in NW-NE- E'lys, and affords more readily available stoppage ports, should adverse weather become an apparent threat for onward travel. Figure 2: Typical summer weather pattern along the central American Coast. Figure 1: Typical winter weather pattern along the Central American Coast.
2010 - 2011