To better communicate the risk of severe weather, outlooks issued by the NOAA National Weather Service Storm Prediction Center will add two new categories effective today. The change is being made to better describe the likelihood of severe weather, and bring better consistency to the risks communicated in the short and medium range forecasts for the nation.
The SPC’s Day 1, Day 2 and Day 3 severe weather outlook categories will change from the current four (see text, slight, moderate, high), to five: marginal, slight, enhanced, moderate and high. The marginal category will replace see text, and the enhanced category will indicate risk levels at the upper end of a slight, but below a moderate. In addition to the words, numbers and colors will be used to convey the threat.
The changes are being made based on feedback from customers. As the NWS continues its efforts to evolve into an organization of the 21st century, this information will better prepare decision makers.
“This change is part of the National Weather Service’s efforts to build a Weather-Ready Nation,” said SPC Director Russell Schneider. “It reflects our increased ability to forecast hazardous severe weather and advances our ability to communicate hazardous weather risk to the public.”
With these changes, the probabilistic information that has long been available and used by professional meteorologists will now be better represented in the graphical information most frequently used by the public. The format changes will also improve the use of SPC severe weather forecasts for customers who incorporate SPC outlooks into GIS systems.
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