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Global Ensemble Forecast System (GEFS) Predictions of Days 1–15 U.S. Tornado and Hail Frequencies
Author(s) -
Gensini Vittorio A.,
Tippett Michael K.
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2018gl081724
Subject(s) - tornado , supercell , probabilistic logic , meteorology , severe weather , environmental science , storm , forecast skill , ensemble forecasting , climatology , tropical cyclone , statistics , mathematics , geology , geography
U.S. severe convective storms have grown to represent a 10 billion dollar annual peril for the insurance industry, and their accurate prediction remains a challenging task. This study examines days 1–15 severe convective storm predictions from the Global Ensemble Forecast System (GEFS). GEFS forecasts are based on the Supercell Composite Parameter and verified against spatially smoothed tornado and hail reports over the periods 1 March to 31 May 2016–2017. Skill is analyzed for deterministic forecasts (ensemble mean Supercell Composite Parameter exceeding specified thresholds) and probabilistic forecasts (fraction of ensemble members exceeding specified thresholds). Deterministic forecasts of tornado and hail activities are statistically more skillful than a random no‐skill reference to days 9 and 12, respectively. Probabilistic forecasts are skillful relative to climatological no‐skill reference to day 9 for tornado and day 12 for hail activity. These results provide a useful baseline for further improvement of tornado and hail forecasts at these ranges.