OTD in 2001, Tropical Storm Allison formed south of Houston, TX from a mid-level circulation that crossed over central America from the eastern Pacific the prior day.

As is often the case with early season named storms, they can tend to be a little sloppy, and "weak" (intentionally in air quotes), and Allison was no exception. In fact, for a while there was a good bit of discussion and debate among some as to whether or not the storm really even qualified as a tropical cyclone, given a structure that in many ways resembled a fully-exposed low-level circulation and what some might refer to as a 'half-a-name' structure.

Allison serves as a reminder that 'weak' does not mean less impactful.
The tropical storm went on to claim dozens of lives across a total of seven states and produce widespread, then record-setting, rainfall totals and extreme flooding.