NOAA (The National Atmospheric and Oceanic Administration) issued a La Nina Advisory last week, after they determined that La Nina conditions had developed in October. La Nina conditions occur when their is an anomalous cooling of the Pacific Ocean sea surface temperatures. This is the opposite of what happens during El Nino, which occurs when there is a warming of sea surface temperatures.
This oscillation will influence weather patterns in the US, since global weather patterns move from west to east. An advisory means that La Nina conditions are expected to persist for 3 months, which would take up most of our winter season. There are only minor correlations in our weather here and La Nina, plus this La Nina is expected to stay weak. On average though, a La Nina winter tends to favor drier and slightly warmer weather.
That's an expected average though. Alabama State Climatologist Dr. John Christy explained to us that although temperatures might average out to slightly above normal, we should still be prepared for a few arctic air outbreaks.
"If the La Nina is weak, there is an increased tendency for
cold Arctic-air outbreaks in the winter."
Dr. Christy also noted that there isn't a strong correlation in precipitation in the Valley during a La Nina winter, but the winter outlook does tend toward persistent drought conditions.
Make sure you're ready for winter before it gets here by preparing for winter weather on the road and at home.