SPC's new conditional intensity categories | Ep. 587

James Brierton and Greg Fishel sat down for a fascinating chat with Evan Bentley, the Warning Coordination Meteorologist at NOAA’s Storm Prediction Center (SPC). If you’ve looked at the SPC severe weather maps recently, you might have noticed some big visual updates.The SPC has officially rolled out its new Conditional Intensity Groups (CIGs)—often referred to as "Intensity Levels"—to Day 1, 2, and 3 convective outlooks.Here is a quick look behind the scenes at what this change means and what James, Greg, and Evan discussed to keep you ahead of the storm:📊 What are Conditional Intensity Groups (CIGs)?In the past, the SPC used a binary "hatched" area on their maps to indicate a 10% or higher chance of "significant severe" weather (like an EF2+ tornado, 2"+ hail, or 75+ mph winds). However, this didn't give forecasters a way to separate a common severe day from a truly catastrophic, historic outbreak without forcing you to dig deep into the written text forecast.The new CIG system replaces that single hatching with a multi-tiered intensity framework. It is conditional, meaning: “If a severe hazard occurs at your location, how intense is it expected to be?”Instead of just forecasting the chance of severe weather, the SPC can now map out the Reasonable Maximum Intensity based on the atmospheric environment and storm mode:Tornadoes (Levels 1 to 3): Level 1 points to a reasonable max intensity of an EF2 tornado. Level 2 targets EF3 potential. Level 3 is strictly reserved for those rare, violent EF4+ outbreak days (the kind of wording reserved for only one or two days a year).Damaging Winds (Levels 1 to 3): Gauges peak wind threats ranging from standard severe gusts (Level 1: 75+ mph), to organized bow echoes or derechos (Level 2: 85+ mph), up to high-end, destructive derecho events (Level 3: 95+ mph).Hail (Levels 1 to 2): Level 1 highlights 2 to 3.5-inch hail (tennis ball to baseball size). Level 2 steps up to the monster, destructive stuff—3.5 inches or greater (softball size).🗺️ The Maps Look Different, But the Risks Haven't Changed!Evan emphasized a major takeaway for our groupies: The baseline 1-to-5 risk categories (Marginal, Slight, Enhanced, Moderate, High) are NOT changing. A Slight or Moderate risk day in the future will represent the exact same historical frequency and general threat level as it did in years past.The difference is that the SPC now has a much more nuanced toolkit. For example, they can now map out a day that has a lower coverage/probability of storms but carries an extremely high-end conditional intensity if a supercell manages to breach the cap.📺 How We'll Be Communicating This to YouAs Greg and Evan talked about in the interview, looking at a map overlaid with multiple types of hatching, probabilities, and risk levels can get incredibly complicated for the public.As broadcasters and weather communicators, our goal at the Carolina Weather Group isn't to bog you down in mathematical weeds or scare you with low-context probability percentages. Instead, we'll be breaking these graphics down into bite-sized pieces: first focusing on your overall chance of being impacted, and then explicitly highlighting the areas where the worst-case scenario or higher-intensity storms are possible.#weather #northcarolina #southcarolina #ncwx #scwx #podcast📹 Join this channel to get access to perks: https://www.youtube.com/channel/UCmhGiYbMDccQcdSjpf87nGg/join🧢 MERCH: https://carolinaweathergroup.qbstores.com/💸 LEAVE A TIP: https://streamelements.com/carolinawxgroup/tip🎙️ SUBSCRIBE TO OUR PODCAST: https://anchor.fm/carolinaweather🔔 SUPPORT US ON PATREON: https://patreon.com/carolinaweathergroup💻 VISIT OUR WEBSITE: https://carolinaweathergroup.com