SPC Conditional Intensity Groups vs the old hatched area

What changed in 2026?

SPC introduced Conditional Intensity Groups in its Day 1–3 severe-weather outlooks. CIG1, CIG2 and CIG3 describe distributions with increasing potential for intense severe hazards, conditional on a severe hazard occurring. Hail uses CIG1 and CIG2, not CIG3.

The earlier significant-severe hatched area generally marked at least a 10% chance of significant severe weather within 25 miles of a point. The new intensity layer separates intensity from occurrence probability. Do not interpret every patterned area as the old 10% significant-severe contour.

Read an outlook in this order

First check the issue time, valid period and geographic area. Next read the categorical risk and the probability for the specific hazard: tornado, wind or hail. Then read the conditional intensity pattern and the written discussion.

A relatively low chance of severe weather can coexist with a high conditional intensity: storms may be sparse, but a storm that develops could be dangerous. A broad severe-weather event can have greater coverage without the highest intensity grouping.

The intensity label is not a promise of a particular tornado rating, wind speed or hail size at an address. It describes the forecast environment and hazard distribution. No intensity shading does not mean no risk.

Outlooks prepare you; warnings prompt action

Use an outlook to review plans and ensure warning methods work. An SPC outlook is not a local warning and should not be used to decide that a warning can be ignored.

If NWS issues a warning for your location, follow its protective instructions regardless of your outlook category or CIG label. Check the official map legend each time; tornado, wind and hail layers answer different questions.

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