Lake effect snow warning

Weather warning indicating heavy snowfall amounts generated by convective lake-effect snow

A lake effect snow warning is a bulletin issued by the National Weather Service in the United States to warn of heavy snowfall accumulations that are imminent from convective snow generated by very cold airmass passing over unfrozen lakes (lake effect snow). The criteria for amounts may vary significantly over different county warning areas.^[1] On October 2, 2017, some National Weather Service Forecast Offices discontinued issuing the Lake Effect Snow Warning, and consolidated it with the Winter Storm Warning.^[2] On October 15, 2018, the National Weather Service discontinued issuing Lake Effect Snow Warnings nationwide all together, and all offices consolidated it with the Winter Storm Warning.^[3] Lake effect snow warnings were reinstated for the 2019–20 winter season.^[4]

Environment Canada's Meteorological Service of Canada issues similar warnings but they are called snowsquall warnings.

Examples


879 
WWUS41 KBUF 171935
WSWBUF

URGENT - WINTER WEATHER MESSAGE
National Weather Service Buffalo NY
235 PM EST Tue Dec 17 2019

NYZ006-180345-
/O.NEW.KBUF.LE.W.0001.191218T1400Z-191219T0000Z/
Oswego-
Including the city of Oswego
235 PM EST Tue Dec 17 2019

...LAKE EFFECT SNOW WARNING IN EFFECT FROM 9 AM TO 7 PM EST
WEDNESDAY...

* WHAT...Heavy lake effect snow expected. Total snow accumulations
  of 6 to 10 inches in the most persistent lake snows. Winds
  gusting as high as 35 mph will produce blowing and drifting
  snow. Snowfall rates may briefly reach 2 to 4 inches per hour.

* WHERE...Oswego county. Greatest accumulations across the Tug
  Hill Plateau, with much lower amounts across lower elevations.

* WHEN...From 9 AM to 7 PM EST Wednesday.

* IMPACTS...Travel will be very difficult with deep snow cover on
  roads and very poor visibility. The hazardous conditions could
  impact the evening commute.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Heavy snow will fall in relatively narrow bands. If traveling, be
prepared for rapidly changing road conditions and visibilities.

Submit snow reports through our website or social media.

&&

Experimental content below...do not use operationally
Please see below links for more information on this experiment
http://www.weather.gov/buf/polygon_pdd
http://www.nws.noaa.gov/os/notification/
pns15lake_effect_snowaaa.htm
To view the experimental polygons please see:
http://www.weather.gov/buf/lespolygon
COORD...4408 7515 4417 7534 4406 7579 4391 7615 
        4383 7623 4348 7623 4346 7561 4353 7548 4371 7531 
        4373 7513 
TIME Y19M12D18T1400Z-Y19M12D18T2000Z
COORD...4340 7586 4346 7581 4352 7644 4347 7659 
        4339 7661 4330 7645 4328 7645 4326 7622 4328 7620 
        4322 7587 
TIME Y19M12D18T2000Z-Y19M12D19T0000Z

&&

$$

Hitchcock

References

^ National Weather Service. "Lake effect snow warning". Glossary - NOAA's National Weather Service. Retrieved 17 May 2011.
^ Central Region Headquarters. "National Weather Service Hazard Simplification" (PDF). National Weather Service. Retrieved November 8, 2017.
^ "National Weather Service Service Change Notice 17-77 Updated" (PDF). Retrieved February 1, 2019.
^ "National Weather Service Service Change Notice 19-63 Updated" (PDF). Retrieved December 18, 2019.

External links

National Weather Service
Federal Emergency Management Agency
Meteorological Service of Canada warning criteria

Severe weather terminology in the United States

Severe
storms

Thunderstorm	Advisory Watch PDS watch Warning
Tornado	Watch PDS watch Warning PDS warning Emergency
Marine thunderstorm	Special marine warning

Winter
weather

Advisories	Winter weather advisory
Winter storm	Watch Warning
Blizzard/blowing snow	Blowing snow advisory Blizzard watch Blizzard warning
Heavy snow	Warning
Lake-effect snow	Advisory Watch Warning
Snow squall	Warning
Ice	Freezing rain advisory Ice storm warning Ice storm watch
Avalanche	Warning Watch Advisory

Tropical
cyclones

Tropical storms	Watch Warning
Hurricanes	Watch Warning
Typhoons	Watch Warning
Cyclones	Watch Warning
Storm surge	Watch Warning

Hurricane local statement
Tropical storm local statement
Tropical depression local statement

Flood

Flood	Watch Warning Advisory
Flash flood	Watch PDS watch Warning Emergency
Coastal flood	Advisory Watch Warning Statement
Lakeshore flood	Warning Advisory Watch Statement
River flood	Advisory Watch Warning
Urban and small stream flood	Advisory

Apparent
temperature

Heat index	Heat advisory Excessive heat watch Excessive heat warning
Wind chill	Advisory Watch Warning PDS warning
Extreme cold	Warning
Freeze	Watch Warning Hard freeze warning Frost advisory Hard freeze watch

Maritime
and
coastal
weather

Marine winds	Small craft advisory Brisk wind advisory Lake wind advisory
Gale	Watch Warning
Storm	Watch Warning
Hurricane-force wind	Warning Watch
Hazardous seas	Watch Warning
Freezing spray	Freezing spray advisory Heavy freezing spray watch Heavy freezing spray warning

High surf

High surf advisory

High surf warning

High surf watch

Wind

Advisory-force winds	Wind advisory
Gale-force winds	High wind watch High wind warning
Major hurricane-force winds	Extreme wind warning

Airborne
particulates

Dust/sand	Blowing dust advisory Blowing dust warning Dust advisory Dust storm warning
Fog/Smoke	Dense fog advisory Dense smoke advisory
Ash	Ashfall advisory Ashfall warning
Air pollution	Air stagnation advisory Air quality alert