Discussion: Persistence of tropical convection in the equatorial East Pacific and Atlantic basins coupled with a high latitude high pressure blocking pattern (negative arctic oscillation) causes the energetic mid-latitude storm track to entrain tropical air making storms over-achieving rainfall and severe weather producers particularly in the Great Plains. Today’s midday GFS OP indicates that waves of heavy rainfall over the next 15 days pile to >12 in. on the Kansas/Oklahoma State Line (Fig. 1). Widespread rainfall amount of >5 in. throughout the Great Plains and Midwest U.S. is indicated by the GFS. River flooding will re-expand and crop regions may become inundated with pooling water if this rainfall occurs as forecast.
Fig. 1: 12Z GFS OP 15-day total rainfall forecast.