A comprehensive data catalog of TCs and their associated PREs occurring between 1998 and 2006 was constructed using radar imagery from the National Climatic Data Center, the National Hurricane Center best-track data, the National Precipitation Verification Unit online Quantitative Precipitation Estimate archive, and the National Weather Service precipitation data gleaned from online sources. The National Centers for Environmental Prediction/North American Regional Reanalysis datasets were used to help identify synoptic and mesoscale forcing mechanisms responsible for PREs. Required criteria for inclusion of an event in the PRE dataset were evidence that the TC circulation advected moist tropical air toward the region of PRE formation, and that maximum rainfall directly attributed to the PRE exceeded a rate of 100 mm in 24 h.
A typical PRE is located ~1000 km ahead of the parent tropical system, occurs 1-2 days prior to the arrival of the TC at the latitude of the PRE, and lasts for ~12 h. significant variability is noted. A middle- and upper-level jet-entrance-region confluence zone well downstream of an approaching TC is a favored synoptic location for PRE development. The orientation of midlatitude troughs and ridges lying poleward of TCs modulated whether, where and when a PRE formed while mesoscale surface boundaries acted as a focus for PRE heavy rainfall. Case study results will be used to show the details of PRE behavior.