- Cold air streams across the warm lakes. Air warms and becomes more humid.
- As the air warms, it becomes less dense and rises.
- As air rises, it cools.
- Cooler, moist air may form clouds and cause precipitation (e.g. rain, sleet or snow).
- After the air has moved some distance over the lake, convection and turbulent exchange have transported the moisture upwards to form clouds.
- Once over land, moisture in the air condenses into snow. Snow created in this way is called lake effect snow.
- As the warmed air reaches the shoreline, additional lifting may occur as the air begins to “pile up.” Air typically moves more slowly over land than over water.
- Hills and elevated land areas on down-wind lake shore areas force air upward. Air cools further, encouraging cloud formation and greater snowfall.
What exactly does "lake effect snow" mean?
"'Lake-effect snow' is the name of the process that we give to precipitation that develops due to a relatively warm lake surface temperature and cold air moving over the top of it," Huyck said. Imagine an amount of cold air - what meteorologists call a "parcel" of air - moving across land.
What are States experience lake effect snow?
Extremely cold air moving into the northeastern U.S. on Jan. 10 led to lake-effect snow bands in areas downwind of the Great Lake, causing dangerous travel conditions.
What does warming mean for lake effect snow?
That's because the open water plays the key role. Lake-effect snow happens when cold air moves across warmer lake water. As warm, moisture-rich air evaporates from the lake's surface, it rises into the much colder air above.
How does lake effect snow occur?
Lesson Objectives
- Describe the factors that create lake effect snow.
- Describe how differences in lake and air temperature relate to lake effect snow.
- Describe weather conditions associated with the movement of frontal boundaries across the Great Lakes region.
- Describe how hills and highlands help form clouds and precipitation.
What are the factors that create lake effect snow?
Lake effect snow forms when cold, below-freezing air passes over a lake's warmer waters. This causes some lake water to evaporate and warm the air. Then, the moist air moves away from the lake. After cooling, the air dumps its moisture on the ground, potentially becoming snow.
What can enhance lake effect snow?
A background presence of upward motion due to synoptic-scale processes such as warm advection aloft or differential vorticity advection aloft can enhance the lake/ocean effect snowfall.
What two components do you need for lake effect snow?
Lake Effect Snow Ingredients A lake or bay of 100 km wide, or larger. (The longer the lake, the greater the distance the air must travel over it, and the greater the convection.) An unfrozen water surface. (If the water surface is frozen, the passing air is unable to pick up a little moisture from it.)
What causes lake effect snow quizlet?
In the winter, lake-effect snows form when cold air moves over warmer lake water. Lake moisture evaporates up into the cold air as the bottom layer of cold air is heated by the warmer lake water. This now-warmed air begins to rise and cool and the moisture within it begins to condense forming clouds and then snow.
What air mass causes lake-effect snow?
What causes lake-effect snow? Continental polar (cP) air masses are associated with lake-effect snow. As the cold dry air passes over the great lakes it picks up heat and moisture, then, as the air mass crosses land again it loses the moisture as snowstorm precipitation due to air mass instability.
Who gets the most lake-effect snow?
Lake-effect snow records In the lake-effect parts of western New York state, for instance, Buffalo, Syracuse and Rochester annually top the nation's list of snowiest big cities, each averaging more than 8 feet a year because of their proximity to lakes Erie and Ontario.
Do patterns in temperature influence lake effect snow?
Increases in temperature may cause areas downwind of the Great Lakes to experience increased lake effect snow, but only if temperatures on land are cold enough to allow snow (rather than rain).
Can you predict lake effect snow?
The HRRR is NOAA's hourly updating, short-term weather model, and is the most commonly used weather model for predicting lake-effect snow. But the HRRR needs accurate water surface temperatures to properly estimate evaporation rates from lake surfaces, which is the main driver of lake-effect snow.
Is lake effect snow heavy or fluffy?
Lake-effect snow is among the fluffiest and driest of snows. The size and water content of snowflakes are dependent upon air temperature and storm origin. Chicago's major snows, fueled by Gulf moisture, occur with temperatures around freezing, have a snow-to-water ratio in the range of 6-10:1, and are heavy and wet.
What type of conditions produce snow quizlet?
Snow forms when the dew point is below freezing and water vapor forms ice crystals or snowflakes.
Why doesnt lake effect snow fall to the north or west of the Great Lakes?
Lake-effect snow generally doesn't fall over the water because it needs the friction and topography of the land to bring out the snow. Winds usually blow west to east in the Northern Hemisphere, so the lake-enhanced snow is pushed to the eastern side of the Great Lakes, Miller said.
Why is there rarely lake effect snow on the northern shores of the lakes?
b. The reason for this event is because the cold air masses flow toward the direction of the southeast. Therefore, the lake-effect snow does not occur in the northern and western part of the Great Lakes region.
How does the lake effect affect snow?
Lake effect snow occurrence and location is mainly dependent on wind (speed and direction) and topography. For instance, wind direction and speed can affect how narrow or wide a snow band is, as well as its length; whereas topography can influence snowfall rate.
How much snow does Lake Effect produce?
Lake effect snow usually occurs during the late fall and winter months and is capable of producing as much as 2-3 inches of snow an hour with event totals ranging from 60-100 inches. Extreme events are often highly localized, such as the Buffalo, NY event that occurred in November 2014 ( NWS, Niziol et al. 1995).
What can detect snow?
Both satellite and ground-based microwave radiometers can identify clouds that contain snow, map snow cover and determine the water content of snow. Ground-based weather radars help determine where snow/precipitation is occurring and how intense it is falling over different areas.
Why does water condense when it's cold?
When cold, dry air moves across large areas of warmer water, the cold air near the surface warms and begins to take on moisture from the lake. Due to differences between the colder air aloft and warmer air near the surface, instability causes water molecules to rise upwards, condense and eventually form clouds.
Where does lake effect snow occur?
The term “lake effect snow” was first used to describe the snow events of the North American Great Lakes Region in the Unites States and Canada, where lake effect snow occurs to the leeward (downwind) side of each lake . Lake Erie is the only lake that routinely freezes each winter, and once it does, lake effect snow seldom occurs.
Which lake freezes in the winter?
Lake Erie is the only lake that routinely freezes each winter, and once it does, lake effect snow seldom occurs. In the U.S. lake effect snow commonly occurs across northern Wisconsin, western Michigan, northwestern New York, northwestern Pennsylvania and the Great Salt Lake in Utah. Image Source: Department of Geography at Hunter College, CUNY.
What are the instruments used to study snow?
Several other instruments are used to study the size, shape and structure of snow particles (disdrometers, Precipitation Video Imagers and particle probes), snow depth (snow tubes), and the water content (precipitation gauges) of the snow that falls to Earth’s surface.
What are the areas affected by lake-effect snow?
These include areas east of the Great Lakes in North America, the west coasts of northern Japan, the Kamchatka Peninsula in Russia, and areas near the Great Salt Lake, Black Sea, Caspian Sea, Baltic Sea, Adriatic Sea, and North Sea .
Where is Lake Effect snow?
Lake-effect snow is uncommon in Detroit, Toledo, Milwaukee, and Chicago, because the region's dominant winds are from the northwest, making them upwind from their respective Great Lakes, although they, too, can see lake-effect snow during easterly or northeasterly winds.
How much snow did Istanbul get in 2005?
In February 2005, a lake-effect snowfall left 50 centimeters (20 in) of snow, and in March 1987, a three-week-long lake-effect snowfall accompanied with strong winds (lake-effect blizzard) left 80 centimeters (31 in) of snow in Istanbul.
What caused the lake effect snowfall in 2000?
Cold northwesterly wind over Great Lakes Superior and Michigan created the lake-effect snowfall of December 5, 2000. Lake-effect snow is produced during cooler atmospheric conditions when a cold air mass moves across long expanses of warmer lake water. The lower layer of air, heated up by the lake water, picks up water vapor from ...
What is the lake effect?
Lake-effect occurring when the air at 850 millibars (85 kPa) is much colder than the water surface can produce thundersnow, snow showers accompanied by lightning and thunder (caused by larger amounts of energy available from the increased instability).
How far away does snow fall from a lake?
As the air mass reaches the other side of the lake, the engine of rising and cooling water vapor pans itself out in the form of condensation and falls as snow, usually within 40 km (25 mi) of the lake, but sometimes up to about 100 mi. The location of common lake-effect bands on the Great Lakes.
What is the effect of water vapor on the leeward shores of lakes?
The lower layer of air, heated up by the lake water, picks up water vapor from the lake and rises up through the colder air above; the vapor then freezes and is deposited on the leeward (downwind) shores. The same effect also occurs over bodies of salt water, when it is termed ocean-effect or bay-effect snow.
What are the factors that affect the organization of lake effect precipitation?
Wind speed and shear are also important factors. The organization of lake effect precipitation is influenced partially by the angle at which the wind crosses the lake. The difference between the direction of the mean wind and the mean wind shear is usually less than 20 degrees.
When was the Lake Effect snowstorm?
Historic Lake Effect Snowstorm of November 2014. In November of 2014, western New York experienced an historic, long-duration lake effect snow event. That storm occurred in two phases; both of which were very well predicted.
What is lake effect snow?
In a hot lake, the cold airmass blow over the lake. The lake is warmer, and it will warm that air mass from below. The lake needs to be unfrozen at 35, 40, and 45 degrees Fahrenheit. Then the air that blows across it from the north or the west can be 10 degrees. So what does warm air do? It wants to rise.
Lake effect snow formation & example
How does the lake effect snow form? Certain parts of the United States get enormous snowfall in the wintertime. That snowfall is called by meteorologists lake effect snow.
Lake effect facts
The greater the temperature difference between the air in the lake, the more moisture is sent to the clouds leading to even more snow. Overall the atmospheric conditions are similar for lake effect rain which starts in the late summer and generally lasts through October.
What is enhanced snow?
Lake enhanced snow refers to snowfall associated with a passing weather system being enhanced by the addition of moisture from the Great Lakes. A storm system that passes to our south can result in lake enhanced snow off of Lake Huron…as cold northeast winds pass across the lake.
What causes buoyancy in water?
Warm water. Heat and Moisture. As the air near the water becomes warm and moist…it becomes less dense than the colder air above it. This creates buoyancy…causing the air to rise. As cold air moves out across a warmer body of water…it picks up heat and moisture.
What is the process of warming the atmosphere from underneath?
Upward motion Downward motion . Any process that warms the atmosphere from underneath can create instability. In addition to warming…adding moisture to the air will reduce its density as well (replacing more dense air molecules with less dense water vapor). Warming a layer of air from below while the air above remains cooler ...
Overview
Formation
Some key elements are required to form lake-effect precipitation and which determine its characteristics: instability, fetch, wind shear, upstream moisture, upwind lakes, synoptic (large)-scale forcing, orography/topography, and snow or ice cover.
A temperature difference of 13 °C (23 °F) (or as past researchers have estimated: between 15 and 25 °C) between the lake temperature and the height in the atmosphere (about 1,500 m or 5,000 f…
Great Lakes region
Cold winds in the winter typically prevail from the northwest in the Great Lakes region, producing the most dramatic lake-effect snowfalls on the southern and eastern shores of the Great Lakes. This lake effect results in much greater snowfall amounts on the southern and eastern shores compared to the northern and western shores of the Great Lakes.
The most affected areas include the Upper Peninsula of Michigan; Central New York; Western Ne…
Elsewhere in the United States
The southern and southeastern sides of the Great Salt Lake receive significant lake-effect snow. Since the Great Salt Lake never freezes, the lake effect can influence the weather along the Wasatch Front year-round. The lake effect largely contributes to the 55–80 inches (140–203 cm) annual snowfall amounts recorded south and east of the lake, and in average snowfall reaching 500 inches (13 m) in the Wasatch Range. The snow, which is often very light and dry because of …
Elsewhere in Canada
Lake Winnipeg, Lake Manitoba and Lake Winnipegosis in Manitoba historically have seen lake-effect snow as early as late October, and it is common throughout early to mid-November. Towards the end of November, the lakes sufficiently cool and begin to freeze, ending the lake-effect snow. A brief period of lake-effect snow is also common near Great Bear Lake and Great Slave Lake in the Northwest Territories during early winter (usually early to mid-October); the lake-effect season fo…
Eurasia
Lake-effect or sea-effect snow occurs in other countries, near large lakes or large sea areas. In Eurasia, it occurs in the regions of the Black Sea in Georgia, Romania, Bulgaria and northern Turkey, the Caspian Sea in Iran, the Adriatic Sea in Italy, the North Sea, the Irish Sea, the Aegean Sea, the Balearic Islands, and the Baltic Sea, as well as areas surrounding the Sea of Japan.
Because the southern Black Sea is relatively warm (around 13 °C or 55 °F at the beginning of win…
United Kingdom
In the United Kingdom, easterly winds bringing cold continental air across the North Sea can lead to a similar phenomenon. Locally, it is also known as "lake-effect snow" despite the snow coming in from the sea rather than a lake. Similarly during a north-westerly wind, snow showers can form coming in from the Liverpool Bay, coming down the Cheshire gap, causing snowfall in the West Midlands—this formation resulted in the white Christmas of 2004 in the area, and most recently …
See also
• Horizontal convective rolls
• Ontario winter lake-effect systems
• Planetary boundary layer
• Sea smoke