La Nina Gone - What's Next?
By Don Day, Jr., Meteorologist
A colder subtropical Pacific (La Nina) that has persisted since the all of 2017 has almost completely faded away. It is typical as we go through spring and into summer for Pacific events (La Nina or El Nino) to fade as water temperature differences in the Pacific become more diffuse.
While the La Nina of the past year was not a strong one, it had a major impact on our weather across the USA. The colder than normal temperatures in the far north, central and far northeast were partly due to the La Nina. Also, La Nina brought above normal precipitation (snow) from the Pacific Northwest across the Northern Rockies and the Northern Plains. On the flip side, La Nina brought warmer and drier conditions to the Central and Southern Rockies along with the Southern Plains.
Since La Nina and El Nino are critical to overall temperature and precipitation patterns across the U.S. we are closely watching the computer models and temperature observations as we head into summer to give us a hint or two about next winter season.
Will the winter of 2018-2019 be a winter dominated by La Nina, El Nino or something in between (La Nada)?
Even though we have complicated computer models that can give us hints at this point in time at what next winter may bring, it usually is not until late August or September before we have a good idea what the Pacific will do next winter.
Below is a forecast from this spring through January 2019. The dashed line shows the average of all the models. The dashed line is slightly above the zero line which would mean a very weak El Nino or a neutral situation.
However, notice there are just as many lines below the zero line as above the zero line which is an indication that all options are on the table. While there is a hint we could have a weak El Nino next fall and winter the possibility of a La Nina is still possible. We will provide an update late this summer on how things are looking for next fall/winter in regards to La Nina/El Nino.