Weather warning indicating winter storm conditions are occurring or expected within 36 hours
A winter storm warning (SAME code: WSW) is a hazardous weather statement issued by Weather Forecast Offices (WFO) of the National Weather Service (NWS) in the United States to alert the public that a winter storm is occurring or is about to occur in the area, usually within 36 hours of the storm's onset.
Generally, a Winter Storm Warning is issued if the following criteria, at minimum, are forecast: snow accumulations usually between or greater than 4 to 7 inches (10 to 18cm), or snow accumulations of usually three inches (7.6cm) or more with significant accumulation of ice (sleet or freezing rain). In the Southern United States, where severe winter weather is much less common and any snow is a more significant event, warning criteria are lower, as low as one inch (2.5cm) in the southernmost areas: as one goes from north to south, the accumulation estimates needed to meet warning criteria lessen. A warning can also be issued during high impact events of lesser amounts, usually early or very late in the season when trees have leaves and damage can result.
Winter Storm Warnings for snow events are issued when winds are less than 35mph (56km/h); if the storm is expected to produce winds above this speed for at least three hours accompanying moderate to heavy snowfall, a blizzard warning will be issued instead or as an upgrade to the winter storm warning. Usually, a large accumulation of ice alone with little to no snow will result in an ice storm warning, or in the case of light freezing rain, a winter weather advisory, a freezing rain advisory, or a freezing drizzle advisory. In lieu of issuing such a statement separately, Winter Storm Warnings can include verbiage indicative of a wind chill advisory or a wind chill warning, if potentially life-threatening wind chill values (determined by local criteria) are forecast to accompany winter precipitation during the warning's duration.
Beginning with the 2008–09 meteorological winter, the National Weather Service consolidated individual precipitation-specific bulletins for winter storms expected to create heavy snowfall (heavy snow warning), lake-effect snow (lake effect snow warning) or sleet accumulations (sleet warning or heavy sleet warning) within the warned area, replacing them with variants of the Winter Storm Warning product outlining the accordant hazards being forecast:
Winter storm warning for heavy snow
Replaced the heavy snow warning
Winter storm warning for heavy wet snow
Same as above, except when the snow will also be wet
Winter storm warning for heavy snow and blowing snow
When the criteria for both a WSW for heavy snow and a winter weather advisory for snow and blowing snow are met [near-blizzard conditions][1]
When both the criteria for a WSW for heavy snow and an ice storm warning are met[3]
Winter storm warning for snow and ice
When both the criteria for a winter weather advisory for snow and an ice storm warning are met
Winter storm warning for sleet and freezing rain
When both the criteria for a winter weather advisory for sleet and an ice storm warning are met
Winter storm warning for heavy lake-effect snow
Replaced the lake effect snow warning in some NWS county warning areas. (2017-2018 season)
Additionally, all of the above warning types may also include verbiage indicative of a wind advisory to indicate strong winds that are expected to accompany the precipitation (e.g., "winter storm warning for heavy wet snow and strong winds").
The generic "winter storm warning" terminology may be used on its own, typically to indicate that all types of winter precipitation (as a mixture or in periods before transitioning between types) are expected in high amounts; however, it may be defined generically at the forecaster's discretion regardless of whether or not this condition is met.
596 WWUS44 KLIX 192043 WSWLIX URGENT - WINTER WEATHER MESSAGE National Weather Service New Orleans LA 243 PM CST Sun Jan 19 2025 LAZ034>037-039-046>048-056>060-064-065-070-071-076>090-MSZ068>071- 077-083>088-200445- /O.UPG.KLIX.WS.A.0001.250121T0600Z-250122T0600Z/ /O.NEW.KLIX.WS.W.0001.250121T0600Z-250122T0600Z/ Pointe Coupee-West Feliciana-East Feliciana-St. Helena-Washington- Iberville-West Baton Rouge-East Baton Rouge-Assumption-St. James- St. John The Baptist-Upper Lafourche-St. Charles-Upper St. Bernard-Upper Terrebonne-Lower St. Bernard-Northern Tangipahoa- Southeast St. Tammany-Western Orleans-Eastern Orleans-Northern St. Tammany-Southwestern St. Tammany-Central Tangipahoa-Lower Tangipahoa-Northern Livingston-Southern Livingston-Western Ascension-Eastern Ascension-Upper Jefferson-Lower Jefferson-Upper Plaquemines-Central Plaquemines-Wilkinson-Amite-Pike-Walthall- Pearl River-Northern Hancock-Northern Harrison-Northern Jackson- Southern Hancock-Southern Harrison-Southern Jackson- Including the cities of Escatawpa, Port Allen, Laplace, Jean Lafitte, Saucier, Chalmette, Tickfaw, Prairieville, Sellers, Centreville, Independence, Donaldsonville, Marrero, Labadieville, Gulfport, Franklinton, New Roads, Sorrento, Geismar, Gramercy, Kiln, Houma, Bayou Sorrel, Thibodaux, Metairie, Pass Christian, Bayou Cane, Salem, Plaquemine, Tylertown, Shell Beach, Slidell, Brusly, St. Martin, Livingston, Paincourtville, Kentwood, Moss Point, Dolorosa, Wade, Westwego, Bogalusa, Jackson, Livonia, Greensburg, Norco, Montpelier, Gautier, Harahan, Necaise, Gretna, Roseland, Amite, Denham Springs, Picayune, Pascagoula, Darlington, Lutcher, Lyman, Walker, McNeil, Ocean Springs, Baton Rouge, Meraux, Delacroix, Bay St. Louis, Crossroads, Destrehan, Poplarville, Wilmer, Felps, French Settlement, Robert, Acy, Vancleave, Clinton, Madisonville, Braithwaite, Fort Adams, Larose, Long Beach, Barataria, Pierre Part, Lettsworth, Covington, Yscloskey, Belle Chasse, Smithdale, Pearlington, Addis, White Castle, Waveland, Diamondhead, Reserve, Gonzales, Whitehall, Akers, Spillman, Folsom, Ponchatoula, Easleyville, Woodville, Alliance, Violet, Raceland, Convent, Killian, Gloster, Dexter, Kenner, Biloxi, Lafitte, Enon, Gillsburg, St. Francisville, Liberty, Mandeville, New Orleans, Bush, Springfield, McComb, Hammond, East New Orleans, and Wakefield 243 PM CST Sun Jan 19 2025 ...WINTER STORM WARNING IN EFFECT FROM MIDNIGHT MONDAY NIGHT TO MIDNIGHT CST TUESDAY NIGHT... * WHAT...Winter precipitation causing moderate to major impacts is expected. Snow accumulations of 3 to 6 inches along and north of the I-10 and I-12 corridor and 1 to 3 inches south of this corridor. There is also a low chance of light ice accumulations along and south of this line. * WHERE...Portions of southeast Louisiana and southern Mississippi. * WHEN...From midnight Monday Night to midnight CST Tuesday Night. * IMPACTS...Roads, and especially bridges and overpasses, will likely become slick and hazardous. Plan on slippery road conditions. The hazardous conditions could impact the Tuesday morning and evening commutes. PRECAUTIONARY/PREPAREDNESS ACTIONS... If you must travel, keep an extra flashlight, food, and water in your vehicle in case of an emergency. The latest road conditions for the state you are calling from can be obtained by calling 5 1 1. Consider delaying all travel. If travel is absolutely necessary, drive with extreme caution. Consider taking a winter storm kit along with you, including such items as tire chains, booster cables, flashlight, shovel, blankets and extra clothing. Also take water, a first aid kit, and anything else that would help you survive in case you become stranded. && $$ HRL/TJS
A winter storm is an event in which wind coincides with varieties of precipitation that only occur at freezing temperatures, such as snow, mixed snow and rain, or freezing rain. In temperate continental and subarctic climates, these storms are not necessarily restricted to the winter season, but may occur in the late autumn and early spring as well. A snowstorm with strong winds and low visibility is called a blizzard.
A winter weather advisory is a hazardous weather statement issued by local Weather Forecast Offices (WFO) of the National Weather Service in the United States when one or more types of winter precipitation—snow, rain and snow mixed, freezing rain, sleet, graupel, etc.—presenting a hazard, but not expected to produce accumulations meeting storm warning criteria, are forecast within 36 hours of the expected onset of precipitation or are occurring in the advisory's coverage area.
A winter storm watch is issued by the National Weather Service of the United States when there is a possibility of heavy snow or potential of significant ice accumulations, without meeting a specific other winter criteria. The watch is typically issued 12 to 48 hours before the storm's expected arrival in the given area. The criteria for this watch can vary from place to place, which is true with other winter weather warning and advisories.
An ice storm warning is a hazardous weather statement issued by the Weather Forecast Offices of the National Weather Service in the United States which indicates that freezing rain produces a significant and possibly damaging accumulation of ice on surfaces. The criteria for this warning vary from state to state, but typically an ice storm warning will be issued any time more than 1⁄4 inch (6.4 mm) of ice at peak is expected to accumulate in an area, else a freezing rain or drizzle advisory is issued; in some areas, the criterion is 1⁄2 inch (13 mm) instead.
This article describes severe weather terminology used by the National Weather Service (NWS) in the United States, a government agency operating within the Department of Commerce as an arm of the National Oceanic and Atmospheric Administration (NOAA).
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. The criteria for amounts may vary significantly over different county warning areas. 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. 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. Lake effect snow warnings were reinstated for the 2019–20 winter season.
This article describes severe weather terminology used by the Meteorological Service of Canada, a branch within Environment and Climate Change Canada. The article primarily describes various weather warnings, and their criteria. Related weather scales and general weather terms are also addressed in this article. Some terms are specific to certain regions.
It is very rare for snow to fall in the U.S. state of Florida, especially in the central and southern portions of the state. With the exception of the far northern areas of the state, most of the major cities in Florida have never recorded measurable snowfall, though trace amounts have been recorded, or flurries in the air observed few times each century. According to the National Weather Service, in the Florida Keys and Key West there is no known occurrence of snow flurries since the European colonization of the region more than 300 years ago. In Miami, Fort Lauderdale, and West Palm Beach there has been only one known report of snow flurries observed in the air in more than 200 years; this occurred in January 1977.
A blizzard warning is a hazardous weather statement issued by Weather Forecast Offices (WFO) of the National Weather Service (NWS) in the United States, which indicates heavy snowfall accompanied by sustained winds or frequent gusts of 35 mph (56 km/h) or greater are forecast to occur for a minimum of three hours. A blizzard tends to reduce visibilities to 1⁄4 mile (400 m) or less.
A blizzard watch was a bulletin issued by the National Weather Service of the United States which meant winds greater than 35 miles per hour, mixed with falling or blowing snow, and visibilities of 1⁄4 mile (0.4 km) or less is forecast for a period of 3 hours or more. A blizzard watch was issued 12 to 48 hours before an expected blizzard event. As the forecast solidifies, a blizzard watch would be either downgraded to a winter storm warning or winter weather advisory for blowing snow or upgraded to a blizzard warning.
A Special Weather Statement is a form of weather advisory. Special Weather Statements are issued by the National Weather Service of the United States (NWS) and the Meteorological Service of Canada (MSC). There are no set criteria for special weather statements in either country.
Rain and snow mixed or sleet is precipitation composed of a mixture of rain and partially melted snow. Unlike ice pellets, which are hard, and freezing rain, which is fluid until striking an object where it fully freezes, this precipitation is soft and translucent, but it contains some traces of ice crystals from partially fused snowflakes, also called slush. In any one location, it usually occurs briefly as a transition phase from rain to snow or vice-versa, but hits the surface before fully transforming. Its METAR code is RASN or SNRA.
A lake effect snow watch was a bulletin issued by the National Weather Service in the United States to warn of heavy snowfall amounts that will be possible from convective snow generated by cold air masses passing over unfrozen lakes. The criteria for amounts may vary over different county warning areas.
A freezing rain advisory was an advisory issued by the National Weather Service in the United States when freezing rain or freezing drizzle was expected to cause significant inconveniences, but did not meet warning criteria.
The 2011 Groundhog Day blizzard was a powerful and historic winter storm that affected large swaths of the United States and Canada from January 31 to February 2, 2011, especially on Groundhog Day. During the initial stages of the storm, some meteorologists predicted that the system would affect over 100 million people in the United States. The storm brought cold air, heavy snowfall, blowing snow, and mixed precipitation on a path from New Mexico and northern Texas to New England and Eastern Canada. The Chicago area saw 21.2 inches (54 cm) of snow and blizzard conditions, with winds of over 60 mph (100 km/h). With such continuous winds, the blizzard continued to the north and affected Eastern and Atlantic Canada. Blizzard conditions affected many other large cities along the storm's path, including Tulsa, Oklahoma City, Kansas City, St. Louis, Springfield, El Paso, Las Cruces, Des Moines, Milwaukee, Detroit, Indianapolis, Dayton, Cleveland, New York City, New York's Capital District, and Boston. Many other areas not normally used to extreme winter conditions, including Albuquerque, Dallas and Houston, experienced significant snowfall or ice accumulation. The central Illinois National Weather Service in Lincoln, Illinois, issued only their fourth blizzard warning in the forecast office's 16-year history. Snowfall amounts of 20 to 28 inches were forecast for much of Northern and Western Illinois.
A Heavy Freezing Spray Warning is issued by the National Weather Service of the United States to warn vessels that rapid accumulation and icing of freezing water droplets due to a combination of cold water, wind, cold air, and vessel or vehicle movement is likely. Accumulation rates of 2 cm per hour or greater must be possible for a warning to be issued, or else a freezing spray advisory would be issued.
The January 2014 Gulf Coast winter storm was a somewhat rare winter storm that impacted the eastern and southeastern United States, as well as Mexico, most notably the Gulf Coast region, which rarely receives frozen precipitation, in late January 2014. The storm came during a period of very cold temperatures across much of the United States, bringing frigid temperatures as far south as the Gulf Coast. The Weather Channel unofficially named it Winter Storm Leon.
Snow in Louisiana is a relatively rare but not unheard of sight because of Louisiana’s subtropical climate. For snow to push into Louisiana, extreme weather conditions for the area must be present, usually a low-pressure system coupled with unusually low temperatures. Average snowfall in Louisiana is approximately 0.2 inches (5.1 mm) per year, a low figure rivaled only by the states of Florida and Hawaii.
The 2020–21 New Year's North American winter storm was a major storm system that brought a wide swath of snow and ice to parts of the High Plains and Central and Northeastern United States during the New Years holiday from December 30–January 2. The system began developing early on December 30, and began spreading wintry precipitation to parts of Texas, coalescing into a low pressure system that formed near the western Gulf of Mexico. The winter storm tracked north and brought heavy snow, ice and strong winds to much of the center of the Midwest and interior parts of the Northeast and New England, causing widespread impacts and travel issues.
The February 15–20, 2021 North American winter storm, also unofficially referred to as Winter Storm Viola, or to some as simply The North Texas Freeze, was a significant and widespread snow and ice storm across much of the United States, Northern Mexico, and Southern Canada. The system started out as a winter storm on the West Coast of the United States on February 15, later moving southeast into the Southern Plains and Deep South from February 16–17. It then moved into the Appalachian Mountains and Northeastern United States, before finally moving out to sea on February 20. The storm subsequently became a powerful low pressure system over the North Atlantic, before eventually dissipating on February 26.
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