The NOAA/CPC monthly drought outlook for the U.S. indicates the Upper Midwest U.S. drought eases in September. However, the southwest Great Plains observes developing drought conditions. The GFS (model) is quite dry and exceptionally hot for the first half of September in the southwest/south Great Plains.

Tropical Disturbance 90L appears to be the strongest tropical wave to move off the West Africa Coast so far this season. Consequently, tropical cyclone models develop 90L with a west to west-northwest 5-day track with intensification to hurricane strength. A category-3 major hurricane is possible in 5 days. This system is a concern for the U.S. East Coast given the potential influence on the steering currents of a west-travelling hurricane in the North Atlantic subtropics.

Although Ida is weakening moving north and later northeastward an immense rain storm will emerge along the path of this storm this week due to lingering tropical characteristics into tomorrow and merging with a frontal system mid-to-late week. Widespread flash flooding will continue!

Last week the Nino34 SSTA zoomed past the La Nina threshold (-0.5C) to -0.9C. The subsurface has also significantly cooled. If this trend continues, La Nina onset would be announced by early October.