Tornado Warning vs. Tornado Watch: What The Alerts Mean As Severe Weather Approaches

The first of two rounds of potentially severe storms is "quickly approaching" the Chicago area, with destructive winds up to 75 miles-per-hour, damaging hail, thunderstorms and tornadoes all threatening the entire region.

The first round of severe thunderstorms is quickly approaching! Expect storms to arrive in the next hour or so for areas southwest of the Chicago metro which will then quickly race to the northeast across the area through ~6 PM. #ILwx #INwx pic.twitter.com/PCqoUM3hnp

— NWS Chicago (@NWSChicago) March 31, 2023

Much of the area, particularly the southern and western suburbs along with portions of northwest Indiana, are now under a moderate risk for severe weather threats, meaning widespread severe storms are likely. The moderate threat level is the fourth of five-scale system from the Storm Prediction Center.

Previously, the threat level was at enhanced risk which is the third level on the system.

UPDATE: High risk of severe storms issued south and west, outside of our viewing area. Parts of our viewing area now upgraded to a moderate risk, which means widespread severe storms are likely.

A tornado watch as also been issued west, just outside of our viewing area. pic.twitter.com/pKVjZPhlWc

— Iisha Scott (@IishaScottNBC5) March 31, 2023

Additionally, the National Weather Service has issued a tornado watch to the west, NBC 5 Meteorologist Iisha Scott reports.

However, as the fast-moving storms quickly approach, that would could extend to the east, or turn into a warning.

MORE: What To Do If You're Driving When Severe Weather, Tornadoes Hit

Here's a breakdown of the differences between the two.

Watches

A watch is issued when conditions are such that a severe weather event, such as a severe thunderstorm, a tornado or a winter event like a blizzard, is possible.

Watches tend to be widespread over large areas, as the NWS uses them when the forecasted movement and location of a storm system is still uncertain.

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When watches are issued, residents are urged to keep an eye on the forecast, and to prepare for the possibility of severe weather, taking extra precautions as needed.

An important reminder...@nbcchicago #Chicago pic.twitter.com/16uaiGyEEN

— Iisha Scott (@IishaScottNBC5) March 31, 2023

Warnings

A warning is issued when a severe weather event is actively taking place. That can include a severe thunderstorm or a tornado, whether that tornado has been observed by trained weather spotters or has appeared as rotation on Doppler radar.

In the event of a warning, residents are urged to take shelter immediately, preferably in an interior room of a structure or in the basement if possible.

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