Why have much of the eastern and southern USA had such a cool summer? In part, it's because El Nino and La Nina, the big bullies of the climate playground, have been on vacation over the past few months.
El Nino (warmer-than-average water temperatures in the tropical Pacific Ocean) and its counterpart La Nina (cooler-than-average water temperatures) are unquestionably the world's climate drivers — and the main influences on weather in the USA.
The El Nino pattern is officially known as the "El Nino Southern Oscillation" (ENSO). And when either El Nino or La Nina are really strong, the world's other climate patterns run and hide.
That's not happened this summer: With tropical Pacific ocean temperatures neither unusually warm nor cold (known as an ENSO-neutral phase), the typically meek and little-known "East Pacific-North Pacific " (EP-NP) pattern has taken over, according to climate scientist Richard Heim of the National Climatic Data Center in Asheville, N.C.
This pattern is partly responsible for the weirdly cool and damp summer over parts of the eastern and southern USA. How cool? Seventeen states, mainly in the South, had a cooler-than-average July, according to the data center. And cities such as Washington, D.C., Atlanta, Nashville and Charlotte are all having an unusually cool August, the National Weather Service reports.
Also, Florida had its wettest July on record.
No comments:
Post a Comment