Atmospheric rivers and the switch to Enso-Neutral
California has seen endless rainfall the past several months coming after much of the state remained in extreme drought conditions. Several low pressure systems have driven in from the Western Pacific ocean driving narrow bands of increased moisture in the lower jet stream. These narrow bands of increased moisture meets with cold fronts off of the Eastern coast causing intense rain and snow showers across California.
Much of the state of California is under a State of Emergency for dangerous flooding conditions. Currently 40 counties remain under this order by the governor of California. Heavy showers are expected to last into Wednesday afternoon as widespread flood warnings continue.
In western portions of California near the Sierra Nevada mountain range, many residents remain trapped due extreme levels of snowfall. In the past 24 hours from 4 pm Monday until 4 pm Tuesday, some areas in higher elevations have seen an additional 9 inches of snowfall.
These intense showers and snowstorms fall in line with what is seen more often during La Nina patterns. Thes past three years, the United States has seen La Nina conditions causing cooler than average conditions in the northwestern region of the U.S. Mid-Missouri typically sees wetter and warmer than average conditions during La Nina spells.
In the past week, La Nina conditions have finally changed towards Enso-Nuetral patterns. This means waters across the Pacific ocean see little variances from west to east causing near average conditions for portions of the midwest.