National Weather Service Updates Tornado Forecasting Maps

The National Weather Service (NWS) Storm Prediction Center (SPC) is implementing updates to its severe weather forecast maps to improve the clarity of storm intensity communication. The SPC, based in Norman, Oklahoma, is tasked with tracking and forecasting severe weather threats across the contiguous United States. In a recent announcement, warning coordination meteorologist Evan Bentley detailed that while the existing risk categories—Marginal, Slight, Enhanced, Moderate, and High—will remain unchanged, the method of indicating storm intensity will be revised.

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Previously, the NWS utilized a “hatching” symbol to denote significant severe weather, which was applied uniformly regardless of the storm's potential severity. The updated maps will introduce three new intensity tiers: Level 1 indicates the possibility of significant severe weather; Level 2 signals a dangerous environment capable of producing intense tornadoes or large hail; and Level 3 is reserved for historic outbreak-level intensity, such as violent tornadoes or intense derechos. This change allows the NWS to communicate the intensity of storms more effectively, without relying on the previous requirement of a 10 percent coverage threshold.

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Liz Leitman, an outlook forecaster, emphasized that the new system will enhance public understanding of severe weather risks. “Instead of telling you ‘yes, there is a risk,’ we can tell you the risk [in a given area] is extreme,” Bentley stated. This shift aims to separate the likelihood of storm occurrence from the potential severity, enabling individuals and communities to better prepare for severe weather events.

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As the NWS rolls out these updates, forecasters are warning that parts of the U.S. may experience multiple days of severe storms in the upcoming week. The agency has indicated that the chances for damaging winds, hail, and tornadoes will peak on Friday, with an Enhanced Risk (level 3 out of 5) in effect. All hazards are expected to remain possible throughout the week.

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While the updates aim to improve public safety, some meteorologists have expressed concerns about the potential for confusion among the public regarding the new intensity tiers. Critics argue that without adequate public education on these changes, the effectiveness of the new system may be diminished.

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• “This is how we communicate storm intensity.” — Evan Bentley, Warning Coordination Meteorologist

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• “It separates the chance of seeing a storm from the power of that storm. It’s a smarter way to be prepared and stay safe.” — Evan Bentley, Warning Coordination Meteorologist

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• “When no intensity area is present, we’re communicating that the vast majority of severe weather is expected to be lower-end severe,” — Liz Leitman, Outlook Forecaster

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The NWS's updates to its severe weather forecasting maps represent a significant step towards enhancing public awareness and preparedness for severe weather events.

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