Much Needed Rainfall Appears in Great Plains Forecast

Discussion: The GFS remains relied upon to project the South America rainfall pattern into late October. Heavy rains are projected across the eastern half of Brazil this week in the core of the drought area (Fig. 1). Wet weather is also projected across Northern Argentina. In the 8-14-day outlook, GFS maintains the wet weather across southwest and eastern Brazil with a remarkable dry transition just to the north across Northern Brazil (Fig. 2). Northern Argentina turns drier in the 8-14-day period.

Wetter forecasts appeared over the weekend for the Great Plains and East-central U.S although models were inconsistent. The GFS is increasingly confident that wet weather appears across the western and northern Great Plains in the 6-10-day period (Fig. 3) shifting eastward and boldly across the Midwest States in the 11-15-day forecast (Fig. 4). The wet risk is supported by an emerging -PNA pattern in western North America causing moisture to extend northward into the Central U.S. from the western Gulf of Mexico. An eastward shifting Madden Julian oscillation across the equatorial Pacific also motivates rainfall.

During the past week, heavy rain reached Ukraine while Southwest Russia remains arid. The outlook for this week indicates widespread rains across Black Sea and eastward while the Ukraine rains shift across Southwest Russia bring much needed precipitation to the ongoing drought (Fig. 5).

Fig. 1-2: The GFS 1-7-day and 8-14-day percent of normal rainfall forecast across South America.

Fig. 3-4: The GFS 1-7-day and 8-14-day percent of normal rainfall forecast across the U.S. AG Belt.

Fig. 5: The GFS 1-5-day percent of normal rainfall forecast across the Black Sea region.