The National Oceanic and Atmospheric Administration’s Storm Prediction Center has introduced a new feature called Conditional Intensity Groups (CIG) to its severe-weather outlooks. Debuting on March 3, 2026, CIGs add a finer level of detail to tornado, wind, and hail threats within the existing five-tier risk framework (Marginal through High).
This blog post explains how CIGs work, what they mean for forecasts, and why they matter for public preparedness and decision-making.
What are Conditional Intensity Groups (CIG)?
CIGs are a refinement tool designed to convey the likely intensity of specific hazards within the SPC’s established risk categories. While the overall categorical scale remains unchanged, CIGs provide hazard-by-hazard intensity designations to show how severe storms could be in a given event.
This approach aims to bridge the gap between broad risk categories and the actual impacts people may experience. Officials emphasize that CIGs do not imply a higher overall frequency or severity of events; rather, they offer clearer information about expected storm impacts.
Forecasters and communicators hope this clarity will help communities better prepare for the kinds of hazards most likely to occur in their area.
Tornado CIGs
For tornadoes, the CIG scale ranges from no level (representing mostly EF-0/EF-1) up to Level 3 (up to EF-4). A “+” indicator is used to signal a small chance for even stronger events than Level 3.
This tiered approach helps communicate that, within a given risk category, tornadoes could vary in intensity from weaker to potentially intense EF-scale events. The goal is to provide more timely context about the potential strength of tornadoes in the forecast area.
Wind CIGs
Wind CIGs illustrate escalating threats from surface gusts to more widespread high-wind events. Level 1 signals gusts greater than 75 mph, while Level 3 corresponds to high-end derechos with gusts likely exceeding 95 mph.
By isolating wind intensity, the SPC can indicate where damaging straight-line winds are most probable and how strong they might be, independent of other hazards in the same forecast.
Hail CIGs
Hail CIGs simplify two defined levels: Level 1 for hail larger than 2 inches in diameter, and Level 2 for hail exceeding 3.5 inches. This differentiation helps convey the potential for severe hail damage in a region, guiding prevention measures and response planning.
Applying CIGs in forecast products
The SPC will incorporate CIGs into Convective Outlook maps and forecast graphics so that meteorologists can show where specific types of severe weather are most likely to reach particular intensity levels. This integration means that people assessing risk can better link the general categorical outlook (e.g., Moderate or High) with concrete expectations for tornado, wind, and hail impacts in their locality.
From a forecasting standpoint, CIGs are a refinement rather than a redefinition of risk. They give forecasters a consistent framework to express hazard-specific intensity without changing the underlying probability forecasts.
The design supports clearer communication to emergency managers, media partners, and the public.
What this means for the public and responders
In practice, CIGs can improve preparedness by attaching more precise information to expected storm impacts.
By communicating not just where storms are likely, but how intense the threats could be, communities can tailor their readiness actions more effectively.
Awareness of hazard-specific intensity helps reduce confusion and supports faster, more targeted responses when warnings are issued.
For communicators, the change offers a clearer narrative: a given outlook may include a broader risk category, yet reveal that certain hazards within that category are more or less likely to reach higher intensity levels.
This nuanced approach aligns with how residents gauge risk in real time and can inform decisions on sheltering, securing property, and coordinating with local responders.
- Hazard-specific intensity within the existing risk categories enhances clarity for tornadoes, winds, and hail.
- Public preparedness benefits from more precise expectations of storm impacts.
- Not a forecast of more storms or higher baseline risk—just smarter communication of what could occur within planned risk levels.
Here is the source article for this story: NOAA’s Storm Prediction Center debuts revamp to severe weather outlooks this season