A Review of Model Guidance for Hurricanes Harvey, Irma, and Maria

This presentation will review model guidance for Harvey, Irma, and Maria. EMC's Model Evaluation Group (MEG) performed exhaustive reviews of guidance for all three storms, and the highlights and overall storylines will be presented. This presentation assesses longer-range predictability as well as model performance on critical short-range mesoscale details, looking at the complete array of deterministic and ensemble guidance at multiple scales from the full spectrum of modeling systems.

Model performance with regards to intensity, track, and rainfall will be presented. If time permits, forecasts for waves and river flow will also be covered. The performance will be assessed with both statistical approaches and subjective evaluations. Initial focus will be on the larger scale with the GFS model and its ensemble, with comparisons made to the deterministic runs and ensemble systems for the ECMWF and UKMET. The HWRF and HMON high-resolution tropical models will be examined next. For the extreme QPF associated with Harvey, the NAM nest, HRRR, and HREF systems will be assessed.

Focus will be on tracks and intensity, with specific attention paid to the rapid deepening of Harvey during the approach to the TX coast, the extreme rainfall from Harvey, the location of the "right turn" for Irma, and the intensity forecasts of Maria as the storm approached Puerto Rico.