From the National Weather Service:
We now have the ability to issue Snow Squall Warnings. Snow squalls are intense, short-lived bursts of heavy snow which can quickly create whiteout conditions. They are usually isolated in coverage. They can often be accompanied by very gusty winds. The biggest impacts are to those traveling as they can create very treacherous road conditions in addition to very low visibility.
Snow Squall Warning details:
- issued when snow squalls appear on radar/satellite or are reported by reliable sources
- visibility 1/4 mile or less in snow with sub-freezing road temperatures
- Plunging temperatures behind an arctic front sufficient to produce flash freezes, along with a significant reduction in visibility from falling and/or blowing snow
- short-fused - 30-60 minute duration
- issued in polygon format
- similar to a severe thunderstorm or tornado warning
- will NOT be issued when Winter Storm Warnings are already in effect
- may be issued with Winter Weather Advisories in effect
- will trigger weather radios
- will eventually be part of Wireless Emergency Alerts (not yet though)
The snow squall warning was pioneered in the northeast U.S. where snow squalls have led to numerous multi-vehicle accidents. Outside of lake effect snow areas, snow squalls are not too typical of an occurrence in our area. Snow squall warnings do give us an enhanced capability in messaging short-lived, transient, heavy lake effect snow bands that would not otherwise prompt a Winter Weather Advisory or Winter Storm Warning. A sample of what a warning would look like on our webpage is below.
Warning Coordination Meteorologist
National Weather Service Chicago/Romeoville