Rain and snow mixed
Encyclopedia
Rain and snow mixed is precipitation
composed of rain
and partially melted snow
. This precipitation can occur where the temperature
in the lower part of the atmosphere is slightly above the freezing point
(0 °C, 32 °F). The METAR
code for this precipitation is RASN.
This precipitation is soft (unlike ice pellets
) and translucent, but it can contain some traces of ice crystals, due to partially fused snowflakes. It is usually a transition phase from rain to snow or vice versa.
The United States
National Weather Service
uses the term sleet to refer to ice pellets
.
, to refer to various mixtures of rain, graupel and snow. Though no "official" criteria exist for the term, in the United Kingdom the term is not used when any accumulation of snow on the ground takes place. It is often used when the temperature of the ground surface is above 0 °C, preventing accumulation from occurring even if the air temperature is marginally below 0 °C; but even then the falling precipitation
must generally be something other than consisting exclusively of snow.
In the United States
, wintry mix generally refers to a mixture of freezing rain
, ice pellets, and snow. In contrast to the usage in the United Kingdom, in the United States it is usually used when air and ground temperatures are below 0 °C. Additionally, it is generally used when some accumulation of ice and snow is expected to occur. During the winter season, a wide area can be affected by the multiple precipitation types typical of a wintry mix during a single winter storm, as counter-clockwise winds around a storm system bring warm air northwards ahead of the system, and then bring cold air back southwards behind it. Most often, it is the region ahead of the approaching storm system which sees the wintry mix, as warm air moves northward and above retreating cold air, causing snow to change to ice pellets, freezing rain and finally rain. The reverse transition can occur behind the departing low pressure system, though it is more common for precipitation to change directly from rain to snow, or for it to stop before a transition back.
Precipitation (meteorology)
In meteorology, precipitation In meteorology, precipitation In meteorology, precipitation (also known as one of the classes of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation...
composed of rain
Rain
Rain is liquid precipitation, as opposed to non-liquid kinds of precipitation such as snow, hail and sleet. Rain requires the presence of a thick layer of the atmosphere to have temperatures above the melting point of water near and above the Earth's surface...
and partially melted snow
Snow
Snow is a form of precipitation within the Earth's atmosphere in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. Since snow is composed of small ice particles, it is a granular material. It has an open and therefore soft structure, unless packed by...
. This precipitation can occur where the temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
in the lower part of the atmosphere is slightly above the freezing point
Freezing Point
Freezing Point is a news journal in the People's Republic of China which has been the subject of controversy over its criticism of Communist Party officials and the sympathetic ear it lent to a Chinese historian who had criticized official history textbooks...
(0 °C, 32 °F). The METAR
METAR
METAR is a format for reporting weather information. A METAR weather report is predominantly used by pilots in fulfillment of a part of a pre-flight weather briefing, and by meteorologists, who use aggregated METAR information to assist in weather forecasting....
code for this precipitation is RASN.
This precipitation is soft (unlike ice pellets
Ice pellets
Ice pellets are a form of precipitation consisting of small, translucent balls of ice. Ice pellets usually are smaller than hailstones. They often bounce when they hit the ground, and generally do not freeze into a solid mass unless mixed with freezing rain...
) and translucent, but it can contain some traces of ice crystals, due to partially fused snowflakes. It is usually a transition phase from rain to snow or vice versa.
The United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
National Weather Service
National Weather Service
The National Weather Service , once known as the Weather Bureau, is one of the six scientific agencies that make up the National Oceanic and Atmospheric Administration of the United States government...
uses the term sleet to refer to ice pellets
Ice pellets
Ice pellets are a form of precipitation consisting of small, translucent balls of ice. Ice pellets usually are smaller than hailstones. They often bounce when they hit the ground, and generally do not freeze into a solid mass unless mixed with freezing rain...
.
"Wintry showers" or "wintry mixes"
Wintry showers is a somewhat informal meteorological term, used primarily in the United KingdomUnited Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
, to refer to various mixtures of rain, graupel and snow. Though no "official" criteria exist for the term, in the United Kingdom the term is not used when any accumulation of snow on the ground takes place. It is often used when the temperature of the ground surface is above 0 °C, preventing accumulation from occurring even if the air temperature is marginally below 0 °C; but even then the falling precipitation
Precipitation (meteorology)
In meteorology, precipitation In meteorology, precipitation In meteorology, precipitation (also known as one of the classes of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation...
must generally be something other than consisting exclusively of snow.
In the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, wintry mix generally refers to a mixture of freezing rain
Freezing rain
Freezing rain is the name given to rain that falls when surface temperatures are below freezing. The raindrops become supercooled while passing through a sub-freezing layer of air, many hundred feet , just above the surface, and then freeze upon impact with any object they encounter. The resulting...
, ice pellets, and snow. In contrast to the usage in the United Kingdom, in the United States it is usually used when air and ground temperatures are below 0 °C. Additionally, it is generally used when some accumulation of ice and snow is expected to occur. During the winter season, a wide area can be affected by the multiple precipitation types typical of a wintry mix during a single winter storm, as counter-clockwise winds around a storm system bring warm air northwards ahead of the system, and then bring cold air back southwards behind it. Most often, it is the region ahead of the approaching storm system which sees the wintry mix, as warm air moves northward and above retreating cold air, causing snow to change to ice pellets, freezing rain and finally rain. The reverse transition can occur behind the departing low pressure system, though it is more common for precipitation to change directly from rain to snow, or for it to stop before a transition back.