A developing marine heatwave off the East Coast of South America is expected to continue strengthening while shifting southward toward and off the Argentina Coast. MHW's in this position during summertime are well-correlated to an upper low-pressure area near the southeast coast of Brazil. Subsidence on the back side of the low leads to a dry climate and increased drought risk in Argentina and possibly Western Brazil.

Tropical Storm Rafael reaches peak intensity in the northwest Caribbean Sea where upper ocean heat is plentiful and the upper shear pattern is light. Rafael maintains intensity across the warm waters of the Southeast Gulf tomorrow night. However, continued northwest tracking beyond the LOOP Current brings Rafael into cooler waters causing some weakening. On the weekend, Rafael encounters a vigorous shear pattern considerably lowering Rafael’s intensity.