Thunderstorm forecast

The daily thunderstorm forecast and storm map for USA is prepared throughout the storm season and refreshed at least once a day to highlight the areas most exposed to severe storms — it answers where thunderstorms are most likely on a given day. Using numerical weather models, we issue the most up-to-date convective outlook, including the expected strength of the storm threat. The map for the next 24 hours is usually updated late in the evening or in the morning.

Dedicated storm outlooks are issued during the spring and summer season. Outside the season, please check our daily forecasts.

We class a storm as severe when at least one of the following is met:

• Level 1 — rain 15–40 mm, wind gusts 60–90 km/h, hail up to 2 cm
• Level 2 — rain 41–70 mm, wind gusts 91–110 km/h, hail 2–5 cm

A storm is extremely severe when at least one of the following is met:

• Level 3 — rain over 70 mm, wind gusts over 110 km/h, hail over 5 cm