A preliminary analysis has shed light on the cause of record rain in Chiba. Experts point to a lingering squall-line system as a key factor. Typically, such systems move quickly, but in this case, it appears to have been unusually slow.

This slow-moving system is believed to have contributed to the deadly downpours that occurred in August. The analysis suggests that the system's lingering presence played a significant role in the heavy rainfall.

Further details on the analysis and its findings are available, providing more insight into the events that led to the record rain and its devastating consequences.