While the Skew-T chart itself isn’t exactly a great way to find composite parameters, the graphics on most sites do provide a way to get insight as to what the composite parameters such as significant tornado and supercell composite say.

By looking at skew-t charts and graphics, you can determine the lapse rates as well.

Skew-Ts will determine a lot about how you formulate your forecast. The composite parameters are just one useful tool to get you to a good target area.

What are the two major composite parameters in storm chasing?

Supercell Composite: The first major composite parameter is the supercell composite. In the most layman’s way to describe it possible, supercell composite simply means how likely it is a supercell will form in the specific environment modeled or sampled. Consequently, this parameter takes into account muCAPE, storm relative helicity, and bulk wind difference. You can read about how SCP is calculated here.

Significant Tornado Parameter: The STP is a favorite amongst model sharers in the Spring on social media. This parameter takes into account (in some combination) CAPE, LCL, storm relative helicity, bulk wind difference, and CIN. Thus, the effective layer favors mixed-layer parameters and the fixed layer uses surface based parameters. If you have to pick one, I’d lean toward the effective layer vs. mixed layer — but each environment is certainly different. You can read about how STP is calculated here.

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