What do risk levels mean when severe thunderstorms are in North Texas’ forecast?

With severe weather expected throughout North Texas on Thursday, the Storm Prediction Center of the National Weather Service and the National Oceanic and Atmospheric Administration issued an outlook for severe weather across the state. The map shows part of North Texas are under enhanced and moderate risk for thunderstorms.

But what does that mean, exactly?

Severe thunderstorms are defined by the weather service as storms capable of producing winds stronger than 58 mph or hail that is an inch or larger. A severe thunderstorm watch means conditions are favorable for severe weather, and a severe thunderstorm warning means such weather is imminent or occurring.

The Storm Prediction Center uses a scale of 1 to 5 to categorize the level of risk for storms in severe weather outlooks. Each category corresponds with a color, and the chance of severe weather increases with each level.

Here are the levels and what they mean.

• General thunderstorm: Designated by yellow, slight risk means isolated to scattered severe storms are possible. In this level, there is “increased confidence” some storms will produce damaging winds, severe hail and/or tornadoes. These storms may be experienced in your geographical area a few times per year.
• Level 1, marginal risk: Designated by dark green, marginal risk means isolated severe storms are possible. Storms with a marginal risk are capable of producing damaging winds and severe hail. The weather service says “localized” tornado threats could happen.
• Level 2, slight risk: Designated by yellow, slight risk means isolated to scattered severe storms are possible. In this level, there is “increased confidence” some storms will produce damaging winds, severe hail and/or tornados. These storms may be experienced in your geographical area a few times per year.
• Level 3, enhanced risk: Designated by orange, this category means scattered to numerous severe storms are expected in the area. There is high confidence that several storms will produce damaging winds, severe hail and/or tornadoes. Such storms may occur in your area only once or twice per year.
• Level 4, moderate risk: Designated by red, moderate risk means scattered to numerous severe storms are expected, and many storms will contain damaging winds, severe hail and/or tornados. These types of storms occur once a year or less.
• Level 5, high risk: This is the highest level, used to designate the most-severe storms. This level means numerous severe storms are expected and there is high confidence that an outbreak of storms will contain tornadoes, damaging winds and/or severe hail. The weather service describes this risk as “very intense storms your area may only experience once or twice in a lifetime.”

The Storm Prediction Service’s outlook on Wednesday afternoon showed an enhanced risk for Dallas, Tarrant, Collin and Denton counties on Thursday. Eastern parts of Dallas and Collin counties are under moderate risk.