Before you use Stormycast
Stormycast is an experimental, automated outlook from a computer model, not an official forecast or warning. It can be wrong, late or missing. For your safety, follow your national weather service and local warnings.
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Stormycast
Machine-learning severe weather outlooks for the whole world, five days ahead.
What the colours mean
The chance of each hazard within 25 miles (40 km) of a point during that place's own day, 6 am to 6 am local solar time.
Tornado any tornado · EF2+ a strong tornadoHail 1 in (25 mm) or larger · 2 in+ giant hailWind 50 kt (58 mph) gusts or damage · 65 kt+ destructive gustsThunder lightning within 25 miles
How it is made
Gradient-boosted trees trained on years of US storm reports and the environments they came from.
Run twice a day from ECMWF's 00Z and 12Z forecasts and NOAA's GEFS ensemble, mixed by how well each has scored · 0.5° grid · days 1–5.
Over the US, day 1 also uses NOAA's HRRR.
Smoothed and calibrated so a 10% area verifies about 10% of the time in the US.
Outside the US it is the same model applied to the local environment, with wind chances scaled by how often local storms bring damaging gusts: treat it as guidance, not a warning.
Track record
Disclaimer
Stormycast is an experimental, automated forecast made by a computer model. It is not an official forecast or warning, and no forecaster checks it before it is published. It can be wrong, late or missing.
For anything that affects safety, follow your national weather service and local authorities: in the US, the National Weather Service and its Storm Prediction Center.
The model learnt from US storms. Elsewhere its chances have not been checked against local storm reports, so treat them as a rough guide only.
Stormycast is not affiliated with or endorsed by NOAA, the National Weather Service, the Storm Prediction Center, ECMWF or any other weather service. The forecasts are provided as they are, without warranty of any kind, and their makers accept no liability for how they are used.
Licence
Forecasts and model: CC BY 4.0 , credit “Stormycast by stormy_sound, Nexradar”.
Credits
ECMWF open data (CC BY 4.0) · contains modified Copernicus Climate Change Service information (ERA5) · NOAA GEFS, HRRR and GOES GLM lightning · NOAA/SPC storm reports · map tiles © Esri.
Made by stormy_sound · part of Nexradar
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