The RAOB Program

Heat Burst Index (for extreme Dry Microburst events)

The Heat Burst Index is an empirical index designed to help forecast the rare "heat burst" event. The heat burst is typically associated with a decaying thunderstorm, which develops into an extreme Dry Microburst event that can produce extremely dry air at well over 100 degrees Fahrenheit with hurricane force winds.  There have been historical reports where heat bursts have carbonized vegetation with brutally hot and dry winds in just a few minutes ( 

This Heat Burst Index is a composite of key thermodynamic properties associated with the "Inverted-V" profile, which is the signature sounding shape often associated with dry microbursts and heat bursts.  This index goes beyond the more limited DMPI (Dry Microburst Potential Index) parameter, and includes lapse-rates, moisture profiles, cloud layers, wind shear, energy potential, inversions, and other physical properties associated with the Inverted-V sounding structure.

This index can out-perform typical CAPE-based storm indices at detecting burst events, because these events often contain little or no CAPE, and they often occur at night. 

Suggested index probability thresholds:

Index     Probability
 > 500    Weak
 > 750    Moderate
>1000    Strong

See other RAOB parameter display options.

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