The Predictability of Formation, Intensity, and Rainfall for Hurricane Barry

Hurricane Barry formed over the northern Gulf of Mexico on 11 July, the result of a mesoscale convective vortex moving over very warm water in a favorable environment. Considering the unusual formation of the tropical cyclone, predictability in the medium range was surprisingly high, with strong signals in deterministic and ensemble systems at impressive lead times. The major forecast challenges actually occurred after landfall and were with respect to QPF. A large swath of rainfall did NOT accompany the storm at landfall and along the path of its remnants, despite model guidance showing widespread totals exceeding 10 inches. Instead, two significant mesoscale rainfall events occurred in the days after landfall, one in central Louisiana and one in southwest Arkansas.

EMC’s Model Evaluation Group (MEG) performed a comprehensive review of model guidance for this event, and the major findings will be presented. The presentation will initially focus on longer-range forecasts of initiation and track, examining deterministic forecasts from the ECMWF model and versions 14 and 15 of the GFS, along with ensemble predictions. The short-range component of the presentation will focus on track and intensity forecasts from the HWRF and HMON tropical modeling systems, along with the global models. Precipitation forecasts will be compared for the global models along with high-resolution guidance from the HRRR, Hi-Res Windows, HREF, and NAM nest, with focus on the forecasts of extreme rainfall in southeast Louisiana that did not verify and on the predictability of the mesoscale events in the days following.