For the second year in a row, the weather phenomenon La Niña is expected to alter the U.S. winter.

The National Oceanic and Atmospheric Administration said Americans could expect myriad conditions caused by the cooling of Pacific Ocean waters.

Generally speaking, La Niña winters are drier and warmer across the southern third of the U.S., and cooler in the northern parts. The Pacific Northwest, the Tennessee and Ohio valleys, and some areas of the Midwest tend to see more rain and snow than average.

A La Niña this winter could have a particularly devastating effect on the Southwest if dry weather prolongs severe drought conditions that have strained the region.

Past La Niñas have created significant market volatility and raised prices for many foods. Major food companies have already been raising prices as they contend with rising costs and supply-chain issues.

La Niña is the lesser-known counterpart to El Niño. During El Niño, the Pacific Ocean waters are warmer, and a west-to-east jet stream across the Pacific brings rain and storms to the U.S., according to NOAA.

“During La Niña, the Pacific jet stream doesn’t reach the United States, leaving instead a big area of high pressure south of Alaska, which reduces storms from coming onshore from the west,” NOAA said Thursday. “The southwestern U.S. is often left hot, high and dry.”

One effect of La Niña tends to be a more active Atlantic hurricane season. While the phenomenon occurs in the latter months of the season, meaning the likelihood of devastating hurricanes are less, there are still significant chances of strong storms that can develop into November, according to NOAA. The agency says there is an 87% chance of La Niña this winter, according to its latest data and advisory.

La Niña’s global impacts are roughly the opposite of El Niño’s. Areas of Indonesia and Australia that usually experience drought during El Niño are wetter during La Niña.