What is the difference between SLGT and MRGL?

SLGT (level 2) means scattered severe storms, multiple cells, some better-organized than MRGL. MRGL (level 1) means isolated short-lived severe storms. SLGT carries roughly twice the probability of severe weather (15% vs 5% within 25 miles) and is the threshold at which most EMAs start coordinating proactively.

What is the SLGT severe probability?

A 15% severe probability within 25 miles of any point. That is the formal SPC threshold for Slight Risk.

What operational activity does SLGT trigger?

SLGT is where most EMAs start active coordination — pre-positioning sirens, activating spotter nets, coordinating shelter messaging. Broadcast meteorologists cut into programming during active hours; school dismissals may be moved earlier. SLGT days produce the bulk of severe-weather climatology and the majority of warned events on a typical year.

What Does SLGT Mean in Weather? — SPC Slight Risk (Level 2)

What Does SLGT Mean in Weather? — SPC Slight Risk (Level 2)SLGT (Slight Risk) is level 2 of 5 on the SPC convective outlook. Scattered severe storms possible — multiple cells, some better-organized than MRGL. The most common active-weather outlook tier and the threshold for active EMA coordination.SLGT stands for Slight Risk — the second of the five severe-weather risk levels on the Storm Prediction Center's categorical convective outlook (level 2 of 5). Scattered severe storms are possible. Short-lived organized supercells producing 1–1.5″ hail or 60–70 mph wind are plausible, and a couple of brief tornadoes can occur. SLGT is the most common active-weather outlook category in the United States.SLGT severe probabilityThe formal SPC threshold for Slight Risk is a 15% severe probability within 25 miles of any point.SLGT vs. MRGLSLGT (level 2) means scattered severe storms, multiple cells, some better-organized than MRGL. MRGL (level 1) means isolated short-lived severe storms. SLGT carries roughly three times the probability of severe weather and is the threshold at which most EMAs start coordinating proactively.SLGT vs. ENHSLGT means scattered storms with the possibility of a few becoming severe. ENH (level 3) means numerous severe storms with several intense and long-lived. The jump from SLGT to ENH represents a meaningful step up — at SLGT, brief tornadoes are possible; at ENH, strong tornadoes (EF2+) become realistic.Common SLGT scenarios

Pre-frontal squall lines.

Multicell clusters with moderate CAPE and shear.

The warm-sector with marginal shear (15-25 kt bulk shear, 1500-2500 J/kg CAPE).

Late-spring/early-summer outflow boundary intersections.

What SLGT triggers operationallySLGT is the threshold at which most emergency management agencies start coordinating proactively — pre-positioning sirens, activating spotter nets, coordinating shelter messaging. Broadcast meteorologists cut into programming during the active hours; school dismissals may be moved earlier. SLGT days produce the bulk of severe-weather climatology and the majority of warned events in a typical year.How SLGT verifiesA typical SLGT verification produces 20–40 severe reports across the outlook area — a mix of wind, hail, and occasional brief tornado reports. SLGT is roughly twice as common as MRGL on active days and is the threshold for organized severe-weather operations.See the full SPC convective outlook guide for the complete scale, probabilistic contours, and storm-mode glossary.

Frequently asked questions

What does SLGT mean in weather?: SLGT is Slight Risk — SPC's level 2 of 5. Scattered severe storms are possible. Short-lived organized supercells producing 1-1.5″ hail or 60-70 mph wind are plausible, and a couple of brief tornadoes can occur. The most common active-weather outlook category.
What is the difference between SLGT and MRGL?: SLGT (level 2) means scattered severe storms, multiple cells, some better-organized than MRGL. MRGL (level 1) means isolated short-lived severe storms. SLGT carries roughly twice the probability of severe weather (15% vs 5% within 25 miles) and is the threshold at which most EMAs start coordinating proactively.
What is the SLGT severe probability?: A 15% severe probability within 25 miles of any point. That is the formal SPC threshold for Slight Risk.
What operational activity does SLGT trigger?: SLGT is where most EMAs start active coordination — pre-positioning sirens, activating spotter nets, coordinating shelter messaging. Broadcast meteorologists cut into programming during active hours; school dismissals may be moved earlier. SLGT days produce the bulk of severe-weather climatology and the majority of warned events on a typical year.
How does SLGT verify on a typical day?: A typical SLGT verification produces 20-40 severe reports across the outlook area — a mix of wind, hail, and occasional brief tornado reports. SLGT is the workhorse tier of the SPC categorical scale.

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