Aviation T-storm Forecasting/Warning: GLM Avg Flash Area vs CWA and SIGMET sizes

One thing that GLM data is going to change for aviation forecasters at the Aviation Weather Center, CWSUs, etc. is Convective SIGMET (C-SIG) and CWA size. As it is now, some aviation forecasters may tend to get a little too "cute" with C-SIG and CWA size, considering C-SIGs and CWAs can be valid for up to 2 hrs or so. As GLM data becomes available to aviation forecasters, I think it is going to open some eyes as to just how much areal extent to lightning there can be in individual t-storms & t-storm clusters/lines/line segments. Consider the following example, which compares GLM average flash area to a C-SIG (again, valid for up to 2 hrs) in NE/KS/N OK. Clearly, the areal coverage of the lightning will extend beyond the boundaries of the C-SIG soon:

GLM avg flash area (w/composite radar) at 2158Z:

C-SIG a few mins later:

- Thomas Bell