As early October arrives, the North Atlantic basin observed sea surface temperature anomalies (SSTA) remain much warmer than normal. Clearly, the best place for tropical cyclone generation/intensification is the western and northern Caribbean Sea where upper ocean heat is immense. Moderate to strong upper ocean heat is also present in parts of the Gulf of Mexico, East of the Bahamas, and central North Atlantic tropics.

The immediate forecast issues include risk of another Gulf of Mexico tropical cyclone. NOAA/NHC identifies a tropical wave southwest of Jamaica having a 50% chance of tropical cyclone development after 48 hours. The 12Z GFS indicates the system develops slowly and eventually reaches the north/northeast Gulf of Mexico Coast early in the 6-10-day period.

The U.S. week 2-4 outlook features sprawling high pressure across the West and Central U.S. producing a nationally drier and warmer than normal climate through mid-autumn. The Gulf of Mexico may be tropically active (after Helene) otherwise rainfall in the U.S. is sparse.

Hurricane models (HWRF and HMON) initialize the 8AM EDT central pressure at 952-953 MB, so slightly too strong. HWRF takes Helene to a 935 MB/138 mph category-4 major hurricane by 8PM this evening with landfall across the Apalachee Bay area late this evening. HMON is not quite as strong, indicating 941 MB/133 mph category-4 major hurricane at 8PM this evening with landfall shortly after midnight in the Apalachee Bay area.