An Overview of NCEP Model Guidance for Hurricanes Harvey, Irma, and Maria (25)

Logan Dawson, I.M. Systems Group, Inc. and NOAA/NWS/NCEP/Environmental Modeling Center, College Park, MD

Tracey Dorian, I.M. Systems Group, Inc. and NOAA/NWS/NCEP/Environmental Modeling Center

Corey Guastini, Pacific Gas and Electric Company

Geoffrey Manikin, NOAA/NWS/NCEP/Environmental Modeling Center

Avichal Mehra, NOAA/NWS/NCEP/Environmental Modeling Center



A review of model guidance for the high-impact storms (Harvey, Irma, and Maria) of the 2017 Atlantic hurricane season will be presented. This presentation will cover the highlights of exhaustive case reviews conducted by the Model Evaluation Group (MEG) at the National Centers for Environmental Prediction's (NCEP) Environmental Modeling Center. This presentation will cover longer-range predictability as well as model performance on critical short-range mesoscale details. Model performance related to track, intensity, and rainfall will be presented.

A complete array of ensemble and deterministic guidance at multiple spatial and temporal scales was evaluated to examine the performance of the full spectrum of modeling systems. Performance was assessed with both objective verification and subjective evaluations.

Initial focus will be on the larger scale with comparisons between track and intensity forecasts from the GFS, ECMWF, and UKMET global deterministic models and their associated ensemble systems. High-resolution track and intensity forecasts from the HWRF and HMON hurricane models will also be examined. Evaluation of more mesoscale details, such as heavy rainfall, will also invoke the HREFv2 ensemble and its deterministic components.

Key forecasting challenges that will specifically be addressed include: the extreme rainfall from Harvey, the location of Irma's &ldquoright turn,&rdquo and the intensity forecasts for Maria as the storm approached Puerto Rico.