On the relationship between extratropical cyclone precipitation and intensity

Extratropical precipitation is largely associated with the passage of cyclones. Here the relative importance of cyclone intensity and moisture availability for cyclone precipitation is investigated using reanalysis data. It is shown that 69% of the event-to-event variability of precipitation in the cyclones' intensification phase is explained by a simple scaling relationship using as predictor the product of cyclone intensity (measured in terms of near-surface wind speed) and total column water vapor (TCWV) in the cyclone region. Differences in the correlation of cyclone intensity with precipitation before and after the time of maximum intensity are potentially related to effects of latent heating on cyclone intensification. For subtropical cyclones, intensity alone is a good predictor of the associated precipitation, whereas at higher latitudes, where moisture availability is more limited, TCWV is an important independent factor. The results from this study may be used to better understand and constrain future regional-scale precipitation changes.