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 Effects of La Nina La Niņa impact on the global climate In the U.S., winter temperatures are warmer than normal in the Southeast, and cooler than normal in the Northwest. Global climate La Niņa impacts tend to be opposite those of El Niņo impacts. In the tropics, ocean temperature variations in La Niņa tend to be opposite those of El Niņo. At higher latitudes, El Niņo and La Niņa are among a number of factors that influence climate. However, the impacts of El Niņo and La Niņa at these latitudes are most clearly seen in wintertime. In the continental US, during El Niņo years, temperatures in the winter are warmer than normal in the North Central States, and cooler than normal in the Southeast and the Southwest. During a La Niņa year, winter temperatures are warmer than normal in the Southeast and cooler than normal in the Northwest. See U.S. La Niņa impacts from the National Weather Service. Also see this graphically in plots of temperature and rainfall anomalies in El Niņo and La Niņa years from Florida State University. An anomaly is the value observed during El Niņo or La Niņa subtracted from the value in a normal year. La Niņa features colder than normal sea surface temperatures in the tropical Pacific Ocean. La Niņa often implies drier than normal conditions in the Southwest in late summer, the Southwest and central Plains in the fall and the Southwest and Southeast in the winter. In contrast, the Pacific Northwest is likely to be wetter than normal in the late fall and early winter with the presence of a well-established La Niņa. Temperature wise, La Niņa winters are usually warmer than normal in the Southeast and colder than normal in the Northwest. La Niņa can bring a wet and cold early winter to the Northwest US, a something skiiers want to hear. The long-term climate outlook issued by NOAA this week calls for warm and dry conditions in the Southwest during July, August and September, and continuing through the fall and winter. This is of particular concern because the area encompassing Arizona, New Mexico and much of Texas is already quite dry. The Gulf Coast states to east of Texas, also currently quite dry, are forecast to have normal chances of precipitation in the summer months. According NOAA , cool conditions will prevail during the next three months in the northern Great Plains. Dry conditions are expected for interior Washington and Oregon during that time. The dryness forecast for the Southwest is expected to also extend into the central Great Plains in the fall and later into the Southeast in the late fall and winter. Researchers from Texas Tech University say current drought conditions across the southern region of the United States may continue straight through the winter months, meaning less chance of rain, dried-up farm fields and dismal prospects for 1999 agricultural crops. The main reason: La Niņa. La Niņa's effect could mean an economic diaster for the southern US. The sister of El Niņo, La Niņa will have an opposite effect on southern states than El Niņo, making for the potential of an economic disaster. Warmer and dryer are not what the south needs at this point. With very little rain during the past few months, conditions for farmers are worsening by the day while the potential for wildfires, like the ones in Florida, continues to grow. The warmer and dryer conditions also affect the average person who is trying to keep his or her lawn or garden in top-notch shape. One hope for rain is the effect La Niņa could have on this year's hurricane season. The cooling of the eastern Pacific Ocean by La Niņa could make for a severe hurricane season along the Gulf and Atlantic coasts. For southeast states along the Atlantic Ocean that may be a bittersweet pill to swallow. However, the last hurricane that blew into the Gulf of Mexico and affected Texas and adjacent states was Hurricane Gilbert in 1988, meaning as always, the possibility is slim to none.
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