Winds of change blowing as cooler risks set to return
Happy Monday! Much of the past several weeks have featured a similar synoptic weather headline across North America: Trough west, ridge east. This pattern had led to large scale above-normal temperature anomalies from the Plains eastward to the Mississippi River, exacerbated near the East Coast. But there are growing signs that this pattern will be changing over next few weeks.
Until now, the pattern has been largely driven by the presence of tropical forcing, from the ENSO regions where La Niña conditions have essentially taken over. We can use multiple measures and analytical approaches to understand exactly how the tropical convection is impacting global circulations, one of them being the SOI. This essentially lets us know if the atmosphere is responding in line with an El Niño, La Niña or neither.