Unique (Atlantic warmth/La Nina Modoki) SSTA Pattern In The Forecast

New Long-lead Forecasts From NOAA Include Wet Louisiana/Mid-Atlantic Projections in September. Possible TC Strikes!
08/20/2021, 10:29 am EDT
Gulf Of Mexico SST/SSTA Regime Ahead Of A Tropical Cyclone
08/26/2021, 8:39 am EDT
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Highlight: Unique SSTA regime ahead…Responsible for wet Brazil/East Australia/Indonesia to Southeast Asia.

Discussion: Warm SSTA in the eastern Indian Ocean (negative Indian Ocean Dipole) and the far western tropical Pacific provides increased low-atmospheric moisture to cause widespread convection (thunderstorms). The rising air currents are replaced below by increasing trade wind flow from the east which up-wells cool subsurface water near an east of the Dateline. The cool waters cause a La Nina to initiate with a location bias farther west than normal (La Nina Modoki). Due to the farther west displacement of La Nina than usual the waters in the tropical Atlantic warm and cause another convection zone. There’s a tendency for areas north and south of the convection zone to experience a wet climate. For southern hemisphere spring a wet climate emerges over East Australia and Brazil. Southeast Asia is also wet. Certainly, Indonesia is very wet. Wet climate zones are compensated for by upstream dry zones in East Africa, the Middle East, Mexico and Argentina. The wet signature in the tropical Atlantic is unique and could lead to a significant wet climate in Brazil.