T₂ Method for Computing Maximum Convective Gusts From Frontal or Air Mass Thunderstorms

The T₂ method uses the difference between the maximum surface temperature at the time thunderstorms are expected as a predictor of the WBZ potential temperature at the time probable maximum gust speed to expect from a thunderstorm outbreak. The gust speed is found by the following steps:

1. Have the forecaster determine what time thunderstorm activity will commence and what the maximum temperature will be at that time.

3. Descend moist adiabatically from WBZ to the surface and record this temperature.

4. Subtract this temperature from the predicted maximum temperature at the onset of the thunderstorm activity to find T₂

5. Enter figure 6-2-16 to find the probable range of the expected maximum gust speed. This figure does not yield average gust speeds or

minimum gust speeds. If T₂ is 20C, for example, you would tell the forecaster that the expected maximum gust will be in the 51- to 68-knot range, with a most probable value of 57 knots. You may wish to think of the three lines as "best case," "most probable case," and "worst case."

Privacy Statement - Press Release - Copyright Information. - Contact Us - Support Integrated Publishing