Rain and snow mixed is

precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. ...

composed of a mixture of

rain Rain is water droplets that have condensed from atmospheric water vapor and then fall under gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides water f ...

and partially melted

snow Snow comprises individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes. It consists of frozen crystalline water throughout ...

. Unlike

ice pellets Ice pellets are a form of precipitation consisting of small, hard, translucent balls of ice. Ice pellets are different from graupel ("soft hail") which is made of frosty white opaque rime, and from a mixture of rain and snow which is a slushy ...

, which are hard, and

freezing rain Freezing rain is rain maintained at temperatures below freezing by the ambient air mass that causes freezing on contact with surfaces. Unlike a mixture of rain and snow or ice pellets, freezing rain is made entirely of liquid droplets. The rain ...

, which is fluid until striking an object where it fully freezes, this precipitation is soft and

translucent In the field of optics, transparency (also called pellucidity or diaphaneity) is the physical property of allowing light to pass through the material without appreciable scattering of light. On a macroscopic scale (one in which the dimensions a ...

, but it contains some traces of

ice crystal Ice crystals are solid ice exhibiting atomic ordering on various length scales and include hexagonal columns, hexagonal plates, dendritic crystals, and diamond dust. Formation The hugely symmetric shapes are due to depositional growth, na ...

s from partially fused snowflakes, also called

slush Slush, also called slush ice, is a slurry mixture of small ice crystals (e.g., snow) and liquid water. In the natural environment, slush forms when ice or snow melts or during mixed precipitation. This often mixes with dirt and other pollutant ...

. 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 METAR is a format for reporting weather information. A METAR weather report is predominantly used by aircraft pilots, and by meteorologists, who use aggregated METAR information to assist in weather forecasting. Raw METAR is the most common form ...

code is RASN or SNRA.

Terminology

This precipitation type is commonly known as sleet in most Commonwealth countries. However, the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

National Weather Service The National Weather Service (NWS) is an Government agency, agency of the Federal government of the United States, United States federal government that is tasked with providing weather forecasts, warnings of hazardous weather, and other weathe ...

uses the term ''sleet'' to refer to

instead. In

Ithaca, NY Ithaca is a city in the Finger Lakes region of New York, United States. Situated on the southern shore of Cayuga Lake, Ithaca is the seat of Tompkins County and the largest community in the Ithaca metropolitan statistical area. It is named a ...

, the term Ithacating is used to describe precipitation made of a mix of rain and snow.

Formation

This precipitation occurs when the

temperature Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer. Thermometers are calibrated in various temperature scales that historically have relied o ...

in the lowest part of the atmosphere is slightly above the

freezing point The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends ...

of water The depth of low-level warm air (below the freezing level) needed to melt snow falling from above to rain varies from about and depends on the mass of the flakes and the

lapse rate The lapse rate is the rate at which an atmospheric variable, normally temperature in Earth's atmosphere, falls with altitude. ''Lapse rate'' arises from the word ''lapse'', in the sense of a gradual fall. In dry air, the adiabatic lapse rate is ...

of the melting layer. Rain and snow typically mix when the melting layer depth falls between these values as rain starts forming when in that range. Rain snow mix soundings

"Wintry showers" or "wintry mixes"

Wintry showers is a somewhat informal meteorological term, used primarily in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...

, to refer to various mixtures of rain,

graupel Graupel (; ), also called soft hail, hominy snow, or snow pellets, is precipitation that forms when supercooled water droplets in air are collected and freeze on falling snowflakes, forming balls of crisp, opaque rime. Graupel is distinct from ...

and snow at once. Though no "official" criteria exist for the term, in the United Kingdom the term is not used when any significant accumulation of snow on the ground takes place. It is often used when the temperature of the ground surface is above , preventing accumulation from occurring even if the air temperature near the surface is marginally below ; but even then, the falling

must generally have something else other than exclusively snow. In the

, wintry mix generally refers to a mixture of

, and snow. In contrast to the usage in the United Kingdom, in the United States it is usually used when both air and ground temperatures are below . Additionally, it is generally used when some surface accumulation of ice and snow is expected to occur. During winter, a wide area can be affected by the multiple mixed 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 in a

warm front A warm front is a density discontinuity located at the leading edge of a homogeneous warm air mass, and is typically located on the equator-facing edge of an isotherm gradient. Warm fronts lie within broader troughs of low pressure than cold fro ...

, causing snow to change into 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 freeze directly from rain to snow, or for it to stop before a transition back.

References

External links

AMS Glossary
{{DEFAULTSORT:Rain And Snow Mixed Precipitation Snow or ice weather phenomena he:גשם-שלג is:slydda

Terminology

Formation

"Wintry showers" or "wintry mixes"

See also

References

External links