When we think of all the crazy weather we've had the last few weeks: the flooding and resulting mudslides in California, not to mention the tornadoes near Los Angeles, the heavy rain and snowstorms in the East, and of course the steady stream of low pressure systems that have kept clouds and rain in the forecast for what seems like an eternity in the Brazos Valley and the rest of southern Texas; it's no surprise that many are blaming El Nino. In this case, they may be right.
In a normal year, the fast-moving trade winds in the Pacific move warm surface water into the western portions of the ocean. In the eastern equatorial Pacific, deep ocean water moves upward to fill the void. This water is much cooler, and as a result sea surface temperatures in the east are very cool.
In El Nino years, the trade winds are much calmer, resulting in unusually warm sea surface temperatures in the eastern Pacific. This may not seem important, but the change in water temperature alters the heating pattern of the atmosphere and the jet stream in the Pacific moves farther South. The typical location of the jet stream is moved right over Southern California, Texas, into the Gulf of Mexico and over Florida before moving out into the Atlantic.
The jet stream's location results in more storm systems moving over the southern portions of the U.S. These low pressure systems bring more clouds and rain over these areas, so it's no surprise that Southeast Texas experiences cooler and wetter winters in El Nino Years.
Scientists at the Climate Prediction Center say the current El Nino is the strongest since the winter of 1997-98.
The good news: it appears as through the intensity of the El Nino phenomenon is beginning to weaken. Since the peak of the effect in late December, sea surface temperatures in the equatorial Pacific have slowly been on the decline. However, we still have a while to go. Scientists are projecting this El Nino to last until Spring, likely not normalizing until April or May.