The update adds multiple levels of visual “hatching” that distinguish the potential power of storms, rather than only the probability that they will occur. According to the National Weather Service, the revised maps separate the likelihood of storms from their possible severity, giving communities a clearer sense of when conditions could support particularly dangerous outbreaks.
A New Way to Show Storm Intensity
The Storm Prediction Center (SPC), based in Norman, Oklahoma, issues outlooks for severe weather across the 48 contiguous United States. Its familiar risk categories (Marginal, Slight, Enhanced, Moderate, and High) will remain unchanged under the new system. These levels indicate the probability that severe storms will occur in a given region.
What is changing is the visual pattern known as “hatching,” which appears on outlook maps to indicate areas where significant severe weather is possible. In a video posted to social media announcing the update, warning coordination meteorologist Evan Bentley explained that the hatching now includes three distinct intensity tiers.
Level 1 indicates that significant severe weather may occur. Level 2 represents a more dangerous environment capable of producing intense tornadoes or very large hail. Level 3 is rarely used and signals the possibility of historic outbreak-level events, such as violent tornadoes or powerful derechos.
The earlier version of the map used a single hatching style to signal significant severe weather, regardless of how extreme the threat might be. That meant a forecast involving EF2-strength tornadoes could appear visually identical to one with the potential for EF5-level storms.
Bentley said the revised approach allows forecasters to communicate not only the chance of storms but also the potential magnitude of those storms. Instead of simply indicating whether severe weather is likely, the map can now highlight when the risk environment itself may be unusually dangerous.
Improving How the Public Interprets Severe Weather Threats
Another key change involves how intensity areas are defined on the outlook maps. Previously, the SPC typically applied hatching only when forecasters expected significant severe weather to cover about 10 percent or more of the forecast region.
Under the updated system, that coverage requirement has been removed. According to outlook forecaster Liz Leitman of the SPC, the new design allows intensity risks to appear even when the area of impact may be smaller.
Leitman explained that if no intensity tier appears on the map, it signals that most severe weather in that area is expected to remain on the lower end of the severity scale. This additional context is intended to help viewers distinguish between routine severe storms and situations where atmospheric conditions could support especially destructive events.
According to The Weather Channel, the SPC has been testing these modifications internally since 2021. Over the past four years, forecasters evaluated how the new design performed during real-world severe weather situations before deciding to release it publicly.
The update comes as meteorologists warn that parts of the United States could face several consecutive days of severe weather in the near term. The National Weather Service said earlier this week that damaging winds, hail, and tornadoes could occur on multiple days, with an Enhanced Risk level expected to peak on Friday.
