Charts of the day: Declining river levels to well below “low stage” along the Mississippi River.
Discussion: Late season arid climate in the East-central U.S. has caused Mississippi River levels to lower below “low stage” with Memphis and Vicksburg highlighted.
Medium-range 6-10 Day Forecast Valid September 18-22, 2023 (24-hour change)
Discussion: The 6-10-day forecast toys with the idea of an amplified trough into the Northwest U.S. bringing cooler (and wetter) conditions while pushing the warm/dry ridge to central continent. GFS is strongest with this solution and ECM (pictured above) is weakest.
Medium-range 11-15 Day Forecast Valid September 23-27, 2023 (24-hour change)
Discussion: Models are in good agreement on a coastal Pacific Northwest upper trough while the ridge pattern is causal of warming east of the Continental Divide.
U.S. Medium-range Precipitation Forecast
Discussion: Wet weather ahead of a West Coast trough into the Central U.S. is indicated but not likely with the vigor to raise Mississippi River levels.
Days 16-20 Extended range Temperature Forecast valid September 28-October 2, 2023
Discussion: Deep upper trough on the West Coast while wet weather permeates throughout the Central States but mostly west of the Mississippi River. The outlook is warm for the U.S. to the east of the Divide and hot in Southern Texas/Mexico.