It’s mid-January, the dead of winter — which in Austin is neither dead nor very wintry. Life is clearly thriving, based on the ubiquitous cedar pollen in the air, and temperatures hit a spring-like 70 degrees twice last week. Driving some of the unseasonably warm temperatures is La Niña, a cyclical cooling of the eastern Pacific Ocean that can influence weather patterns in Texas. Here are five things to know about La Niña:
1. Warmer, drier winters: The colder Pacific waters tend to alter the course of the jet stream, pushing storms northward and leaving Texas with drier and warmer than normal weather.
2. Cold air builds: But the milder, more stable weather means Arctic air masses can build up so much that, when they break loose, they can sweep as far south as Texas and bring sharp, significant drops in temperatures.
3. El Niño’s twin sister: El Niño is the warming of eastern Pacific waters near the equator. In Austin, we typically blame it for wetter, cooler and more unsettled weather. La Niña is when the same parts of the Pacific get cooler than normal and the opposite weather patterns occur. Get it now?
4. Effects aren’t alike: La Niña typically means milder winters in Texas, but the Midwest and Northeast sees wetter and cooler seasons.
5. Here until spring: According to the National Oceanic and Atmospheric Administration, La Niña is 85 to 95 percent likely to stay in place for the rest of winter.