abstract: Previous studies identified a monsoon-like summer regime of isolated, diurnally-forced convection across the southeastern US (SEUS), but the geographic extent and onset timing of this regime across the eastern US was unresolved. This study focuses on that question using a high-resolution radar-based precipitation dataset for a seven-year period. It is found that, on average, onset of the summer isolated convection regime begins in late April in South Florida, extends northward to the Carolinas by mid-May, and to the Canadian border by the end of May. Onset then extends westward from the mid-Atlantic region to just beyond the Mississippi River and as far as east Texas by mid-June. The timing and geographical extent of onset are consistent with previous findings linking this regime with the spring to summer westward migration of the North Atlantic Subtropical High into the SEUS. These results are consistent with the establishment of a more prominent monsoon-like precipitation regime centered in the SEUS as the Earth warms.
Rickenbach et al. (Sat,) studied this question.