Presence of an upper-level low-pressure trough in the upper troposphere developed late last spring and lingered through meteorological summer. The upper trough is weaker in late August but still evident stretching from the Bahamas southwestward. The last time a tropical upper tropospheric trough was present during August in a vivid character was 2013 and during a weak La Nina climate.

Category-4 Typhoon Hinnamnor just-misses China to the east this weekend as intense drought continues. The immense California heatwave ahead peaks in strength next Tuesday. NOAA 30-day forecasts widen Midwest and Northeast drought while implicating Louisiana for September hurricanes.

ECMWF indicates the most likely location for tropical cyclones to develop that can become hurricanes and make landfall on the U.S. Coast is in the Gulf of Mexico for the last third of September and into early October. This season's core activity arrives late and lasts longer than usual!

Circumstances leading to an unusually dry mid-troposphere during August should start to ease in early September and allow tropical cyclone development to occur and flourish in some sectors. Tropical Disturbance 91L in the central North Atlantic tropics has a chance to become a tropical cyclone while an uptick in southwest Gulf of Mexico and outer North Atlantic tropics activity is likely by late this week.