An assessment of the weather attributes included in operational Convective SIGMETs

Convective SIGMETs (C-SIGs), issued hourly by the AWC, include various attributes about the weather, such as lines versus areas, embedded versus isolated convection, the direction and speed of movement, and severe surface hazards. A five-year retrospective of C-SIGs is performed to quantify the range of information included in C-SIGs and how that may impact how end-users interpret and use C-SIGs. Some attributes are used very rarely and/or inconsistently. These include descriptions of storm morphology, lines, and possible flags for severe hazards. It is presumed that rare or inconsistent deployment of these attributes may lead to end-user confusion as to whether a particular reaction is merited on their part. Severe hazards are compared against SPC storm reports to assess their accuracy. It is found that the C-SIG flags for these hazards tend to have a high bias. Moreover, it is noted that most of the storms within a given C-SIG that is flagged severe are not severe, thus raising questions about whether this information is beneficial or misleading. Thoughts on how these idiosyncrasies may be addressed in the future will be posited.