Western Hemisphere Warm Pool

The Western Hemisphere Warm Pool (WHWP) is a region of sea surface temperatures (SST) warmer than 28.5°C that develops west of Central America in the spring, then expands to the tropical waters to the east. The Western Hemisphere Warm Pool (WHWP) is a region of sea surface temperatures (SST) warmer than 28.5°C that develops west of Central America in the spring, then expands to the tropical waters to the east. The WHWP includes the tropical Atlantic Ocean (TNA) east of the Lesser Antilles, Caribbean Sea, Gulf of Mexico, and eastern north Pacific Ocean (ENP). A WHWP heating cycle begins with warmth in the eastern North Pacific in the spring. A dipole pattern off Central America appears due to surges of cooler, drier air through the gap at the Isthmus of Tehuantepec. During spring, the warm pools grow and merge. Their warmth and moisture feed the Mexican monsoon. By summer, the warmth spreads across the Gulf of Mexico and Caribbean areas.