As observed last August, a large region of warmer-than-normal sea surface temperature anomalies (SSTA) in the west/northwest North Atlantic basin correlated to a blocking high pressure ridge over northeast North America caused Major Hurricane Harvey to stall over Texas and produce 50 in. of rain in the Houston area. A similar set-up is in-place this week (into next) to cause Florence, forecast to become a major hurricane to also stall in the Mid-Atlantic region bringing historical and catastrophic flooding.

Operational forecast models indicate Hurricane Florence will approach and possibly strike the U.S. East Coast mid-to-late next week. The environment to support a major hurricane off the East Coast next week is excellent. Tropical cyclone models indicate Florence returns to major hurricane status southeast of Bermuda early next week. Florence is likely to maintain major hurricane intensity tracking west of Bermuda toward the U.S. East Coast next week.

Upper shear is preventing Gordon from full organization despite presence over very warm Gulf of Mexico waters. However, the warm Gulf and slightly less shear later today enables Gordon to become a hurricane moving inland the west coast of Mississippi late this evening. High flood risk due to 6-10 in. of rain is expected with Mississippi hardest hit.

Current and projected warm SSTA in the central/east-central tropical Pacific Ocean drives heavy rainfall while areas to the west such as Australia are in a subsidence region causing more dry climate.