The 12Z GFS 15-day forecast is much wetter across most of the eastern half of the U.S. If so, much needed rainfall occurs in the Mississippi River Valley where river levels have been very low in recent weeks.

“If only it were December” was probably a common expression amongst meteorologists, energy traders, and analysts yesterday as the 1200 GMT GFS produced a classic high latitude high pressure blocking pattern to cause a chilly longwave trough to appear in the East U.S. in the 11-15-day period.

During the week of Sep. 19-25, the verified temperature anomalies across Paraguay averaged an impressive +7C while interior Southeast Brazil was +4C to +7C. However, outside of this very hot region, the temperature anomalies for the week were not nearly as hot. Recent 1-5-day and 6-10-day temperature anomaly forecasts by GFS are much too warm incorrectly indicating too much anomalous heat.

The 2023 season so far is more active than normal with 17 tropical storms, 6 hurricanes, and 3 major hurricanes. The amount of activity so far and outlook for the remainder of the season implies the consensus seasonal forecasts will be accurate.