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Atmospheric Stability API Parameters

Convective Available Potential Energy (CAPE) | Convective Inhibition (CIN) | Lifted Index | Convective Categories | Thunderstorm Probability| Thunderstorm Height

Convective Available Potential Energy (CAPE)

The convective available potential energy (given in joules per kilogram air) is the amount of energy a parcel of air would have if lifted a certain distance vertically through the atmosphere. Any value greater than 0 J/kg indicates instability and an increasing probability of thunderstorms and hail.

cape:Jkg

It is also possible to get the mean, maximum or minimum of the convective available potential energy of an indicated time interval.

cape_<measure>_<interval>:Jkg

Available measures: mean, min, max

Available intervals: 1h, 2h, 3h, 6h, 12h, 24h, 48h, 72h

Examples

Convective Inhibition (CIN)

The convective inhibition (given in joules per kilogram air) is the amount of energy required to lift the parcel to the level of free convection (LFC). While high values (150 J/kg and above) of CIN suppress thunderstorm development, lower CIN values suggest favorable thunderstorm development conditions (i.e. when CIN is 30 J/kg or less).

cin:Jkg

Examples

Lifted Index

The lifted index (given in Kelvin) is the difference between the temperature of the environment and that of an air parcel lifted adiabatically to a given pressure height in the troposphere, usually 500 hPa. The atmosphere at the given height is stable for positive values of the lifted index and unstable for negative values. When the value falls below -2, thunderstorms are anticipated. and for lower values, especially those below -6, severe weather is expected.

lifted_index:K

The mean, maximum or minimum of the lifted index over an indicated time interval are also given.

lifted_index_<measure>_<interval>:K

Available measures: mean, min, max

Available intervals: 1h, 2h, 3h, 6h, 12h, 24h, 48h, 72h

Examples

Convective Categories

Convective categories denote the convective potential of clouds. A high category (category 3 and above) indicates the potential for strong convection and the development of thunderstorm clouds. 

convective_categories_<interval>:idx

Available intervals: 1h, 2h, 3h, 6h, 12h, 24h

CategoriesDescriptionMeaning
0No convectionNo or only very shallow convective clouds.
1Shallow convectionShallow convective clouds with no potential for precipitation.
2Weak convectionSmall-scale convective clouds with potential for isolated showers.
3Moderate convectionPotential for significant showers and possible thunderstorm development.
4Heavy convectionPotential to form heavy thunderstorms.
5Severe convectionPotential to form severe thunderstorms.

Example:

Thunderstorm Probabilities

Gives the probability of a thunderstorm to occur.

prob_tstorm_<interval>:p

Available intervals: 1h, 2h, 3h, 6h, 12h, 24h

Examples

  • Show a thunderstorm probability forecast for the next two days: Prob tstorm
  • Below is an image of the thunderstorm probabilities on June 28th at 15 UTC over Europe:
    https://api.meteomatics.com/now/prob_tstorm_1h:p/70,-15_35,30:0.1,0.1/html Probability tstorm

  • https://api.meteomatics.com/now/prob_tstorm_12h:p/70,-15_35,30:15,15/json

    {"version":"3.0","user":"api-test","dateGenerated":"2018-02-21T14:51:41Z","status":"OK","data":
[{"parameter":"prob_tstorm_12h:p","coordinates":
[{"lat":35,"lon":-15,"dates":[{"date":"2017-08-01T00:00:00Z","value":12.9}]},
{"lat":35,"lon":0,"dates":[{"date":"2017-08-01T00:00:00Z","value":44.2}]},
{"lat":35,"lon":15,"dates":[{"date":"2017-08-01T00:00:00Z","value":23.4}]},
{"lat":35,"lon":30,"dates":[{"date":"2017-08-01T00:00:00Z","value":86.4}]},
{"lat":50,"lon":-15,"dates":[{"date":"2017-08-01T00:00:00Z","value":16.1}]},
{"lat":50,"lon":0,"dates":[{"date":"2017-08-01T00:00:00Z","value":14.3}]},
{"lat":50,"lon":15,"dates":[{"date":"2017-08-01T00:00:00Z","value":22.2}]},
{"lat":50,"lon":30,"dates":[{"date":"2017-08-01T00:00:00Z","value":11.4}]},
{"lat":65,"lon":-15,"dates":[{"date":"2017-08-01T00:00:00Z","value":11.8}]},
{"lat":65,"lon":0,"dates":[{"date":"2017-08-01T00:00:00Z","value":13.6}]},
{"lat":65,"lon":15,"dates":[{"date":"2017-08-01T00:00:00Z","value":21.5}]},
{"lat":65,"lon":30,"dates":[{"date":"2017-08-01T00:00:00Z","value":17}]}]}]}

Thunderstorm Height

Gives the height of a thunderstorm during the requested interval. A value is returned only if a thunderstorm occurence is likely. If m or ft are queried as a unit then the value above sea level is returned.
If the likelihood is none, a value of -666 is returned. In case no data is available, a value of -999 is reutrned.

tstorm_height_<interval>:<unit>

Available intervals: 1h, 2h, 3h, 6h, 12h, 24h

Available units: m, ft, FL, hPa

Examples