EDITION 12 FOR 2016 SAILING DIRECTIONS PUB 120 (PLANNING GUIDE) PACIFIC OCEAN AND SOUTHEAST ASIA. SAILING DIRECTIONS PACIFIC OCEAN. PLANNING GUIDE. PACIFIC OCEAN PILOT. Original text by the USA NATIONAL GEOSPATIAL-INTELLIGENCE AGENCY. The surface waters of the Pacific are driven east to west by trade winds to form the North and South Equatorial currents. The North Equatorial Current has its axis approximately on the parallel of 15 N., and the South Equatorial Current generally follows the Equator. Between the two is the Equatorial Countercurrent flowing eastward. The South Pacific Ocean is generally warmer and less subject to wide variability in temperature. The lack of land also allows low pressure systems to travel a nearly circumpolar route S of 40 S. Lows forming to the N also move SE toward this belt. This is an area of year round clouds, precipitation, and strong winds. In the Southern Hemisphere, lows have a clockwise circulation, while high pressure systems have a counterclockwise circulation. To the N of the "roaring 40's" lies a large semi-permanent high which varies only slightly from winter to summer. It is centered closest to the Equator (30 S) in summer.... ..... Thunderstorms are more likely in the W islands than in the E part. They occur on up to 22 days annually at Koror and on about 10 days .."