Related: CWSU Center Weather Advisories Graphical-AIRMETs PIREPs TAFs Temp/Winds Aloft
Backend documentation for those wishing to script against this download portal.
Shapefile DBF schema:
Field 0: Type=C/String, Title=`NAME' Combination of label and type fields Field 1: Type=C/String, Title=`LABEL' SIGMET label Field 2: Type=C/String, Title=`TYPE', One Character SIGMET type Field 3: Type=C/String, Title=`ISSUE', Issuance UTC Time Field 4: Type=C/String, Title=`EXPIRE', Expiration UTC Time