Discrepancies Encountered in Calculating Stability Indices

At ERH we have been routinely running an AFOS applications program that evaluates the likelihood of flash flooding (FLASHFLOOD.SV). While checking out the results for the July 2 122 run, we noticed a wide discrepancy between the program's calculated K index for Wallops Island (WAL) and that appearing on NMC's LI/KI plot (NMCGPHPØL). The program gave a K of 12, while the NMC plot showed a K of only 2. The lifted index differed also, but by only 2 units. This discrepancy could be attributed to different numerical calculation methods, but the difference in K's was too great to be explained that easily. We decided to investigate further.