Quantitative precipitation estimate (QPE) and forecast (QPF) exceedance comparison with flash flood reports

Flash flooding remains a challenging prediction problem, which is exacerbated by the lack of a universally accepted definition of the phenomenon. In this article, we extend prior analysis to examine the correspondence of various combinations of quantitative precipitation estimates (QPE) and precipitation thresholds to observed occurrences of flash floods, additionally considering short-term quantitative precipitation forecasts from a convection-allowing model. Consistent with previous studies, there is large variability between QPE datasets in the frequency of “heavy” precipitation events. There is also large regional variability in the best thresholds for correspondence with reported flash floods. In general, Flash Flood Guidance (FFG) exceedances provide the best correspondence with observed flash floods, except in the interior western US where recurrence interval thresholds (for the southwestern US) and static thresholds (for the northern and central Rockies) provide better correspon..., QPE and QPF data were collected from the NOAA HPSS for the seven-year period 2015-2021. All data were interpolated to the 3-km HRRR grid. Exceedances of precipitation thresholds (fixed thresholds, average recurrence intervals, and ratios of flash flood guidance) were determined on the 3-km grid. These exceedances were then upscaled to a 60 km grid for contingency table evaluation against flash flood reports. More details are provided in the manuscript., Python is the preferred method to handle these netCDF files., # Quantitative Precipitation Estimate (QPE) and Forecast (QPF) exceedances of precipitation thresholds

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The dataset consists of a number of QPE datasets, in addition to QPF from the High-Resolution Rapid Refresh. The data are on a 60 km grid, and represent binary exceedances of various precipitation thresholds (fixed, average recurrence intervals, and ratios of flash flood guidance thresholds). The grids can be compared with observed flash flood reports on the same grid. QPE data have been subjected to the automated quality control procedure described in the associated paper.

## Description of the data and file structure

Data are zipped up into files named {qpe}*{duration}*{threshold}.zip.

{qpe} can be Stage IV QPE (stageIV), radar-only MRMS (mrms), gauge-corrected MRMS (mrmsGC), CCPA (ccpa), or HRRR QPF (hrrr).

{duration} can be 6h or 1h. For HRRR, we also include 6-12h, as well as 3-4h and 6-7h, to examine QPF at different forecast lead times.

{threshold} varies among fix...