Ok, so in Kansas, the altitude layer at 850hPA roughly equates to 5,000 feet MSL. Only counter-intuitive bit happens with some obvious extreme examples. Take Pike's Peak in Colorado for instance. The surface is ~14,000 adjusted for whatever pressure altitude, which is well above the 5000 msl value. Same for Denver, right? Should I use the 5,000+ in lieu of the surface? Thanks for the reply!