|Created with the Web Accessibility Wizard||Slide 27 of 45|
Eta 5-hour forecast sounding at ELM, with the boundary motion, valid 17 UTC on the 6th.
The white line on this diagram is the boundary motion, as determined by the observed movement of the line of thunderstorms. The 0-3 km shear vector indicated on this pre-storm sounding is perpendicular to the boundary, indicating a favorable environment for storms to merge into a line. This slide also indicates that individual storms would tend to fall behind the fast-moving boundary, indicating strong front to rear storm relative flow, and a storm structure that was likely tilting up-shear (as in slide 10).