Severe weather composite chart to find the triggers for severe thunderstorms: this case is from 26th of March 1948 at 00 GMT. Features are 500-mb features in blue, 850-mb features in red and green, and surface frontal analyses and 60°F dewpoint in black. The wavy green lines indicate moisture axes at 850 mb and the red dotted lines the axes of highest temperatures at 850 mb. Maximum observed wind speeds are indicated; many winds were missing at 500 mb.