K-Index is a measure of thunderstorm potential based on the vertical temperature lapse rate, and the amount and vertical extent of low-level moisture in the atmosphere.
| K= 0 to 18 | Stable. No Thunderstorms |
| K= 19 TO 20 | Marginally unstable. Thunderstorms Unlikely. |
| K= 21 TO 25 | Moderately unstable. Isolated Thunderstorms. |
| K= 26 to 30 | Widely Scattered Thunderstorms |
| K= 31 to 35 | Numerous Thunderstorms |
| K= 36 to 40 | Very Unstable. Thunderstorms Very Likely |
| K=> 40 | Extremely Unstable. 100% Chance of Thunderstorms |
Other UKAWC Stability Indices:
| Lifted Index (LI) | CAPE | CIN | Showalter Index | SWEAT | Total Totals |
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