FA-71198 / Weather index computation / Member archive

K-index and Total Totals: 700 hPa depression sign · case 03

Dry mid-levels increase the K-index instead of suppressing it.

Member previewVariant 3 · 3 implementations · 8 checks per implementation

Case contract

K = (T850 - T500) + Td850 - (T700 - Td700); VT = T850 - T500; CT = Td850 - T500; TT = VT + CT. Thunderstorm potential from K: <20 none, <=25 isolated, <=30 widely scattered, <=35 scattered, else numerous. Severe flag "severe possible" when TT >= 50 else "weak". Return [K, TT, potential, flag].

Why this case matters

Convective outlooks use K and TT as quick stability screens.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
sounding 850 21/6 700 5/-14 500 -7	`[53, 41, "numerous", "weak"]`	`[15, 41, "none", "weak"]`	Failed

MEMBER ARCHIVE

The complete case is available to members.

This record includes three runnable implementations, regression fixtures, execution results, and source hashes.

Member access is invitation-based. Sign in with your invited account to inspect the sources.