Local forecast by
"City, St" |
|
 |
|
Home > Glossary
| |
Acid PrecipitationPrecipitation, such as rain, snow or sleet, containing relatively high concentrations of acid-forming chemicals that have been released into the atmosphere and combined with water vapor; harmful to the environment.Antedecent Precipitation Index(Abbrev. API) - an index of moisture stored within a drainage basin before a storm.Effective Precipitation1) That part of the precipitation that produces runoff.
2) A weighted average of current and antecedent precipitation that is "effective" in correlating with runoff.
3) That part of the precipitation falling on an irrigated area that is effective in meeting the consumptive use requirements.Float Recording Precipitation gageIn hydrologic terms, a rain gage where the rise of a float within the instrument with increasing rainfall is recorded. Some of these gages must be emptied
manually, while others employ a self-starting siphon to empty old rainfall amounts.Hourly Precipitation Data (HPD)It contains data on nearly 3,000 hourly precipitation stations (National Weather Service, Federal Aviation Administration, and cooperative observer stations) in inches to tenths or inches to hundredths at local standard time. HPD includes
maximum precipitation for nine (9) time periods from 15 minutes to 24 hours, for selected stations. Mean Areal Precipitation(abbrev. MAP)- The average rainfall over a given area, generally expressed as an average depth over the area.Mixed PrecipitationAny of the following combinations of freezing and frozen precipitation: snow and sleet, snow and freezing rain, or sleet alone. Rain may also be present.Orographic PrecipitationPrecipitation which is caused by hills or mountain ranges deflecting the moisture-laden air masses upward, causing them to cool and precipitate their moisture.Point PrecipitationPrecipitation at a particular site, in contrast to the mean precipitation over an area.PrecipitationThe process where water vapor condenses in the atmosphere to form water droplets that fall to the Earth as rain, sleet, snow, hail, etc.Precipitation AttenuationThe loss of energy that radar beam experiences as it passes through an area of precipitation.Precipitation ModeThe standard, or default, operational mode of the WSR-88D. The radar automatically switches into precipitation mode from clear-air mode if the measured reflectivity exceeds a specific threshold value. The precipitation mode of NEXRAD is more sensitive than previous weather radars. The minimum detectable reflectivity in NEXRAD's precipitation mode is 5 dBZ, compared to 28 dBZ with the old WSR-57.Precipitation Processing SystemThe WSR-88D system that generates 1-hour running, 3-hourly, and running storm total precipitation accumulations. Five functional steps are performed to calculate the best estimate of precipitation: 1) development of a sectorized hybrid scan, 2) conversion to precipitation rate, 3) precipitation accumulation, 4) adjustment using rain gages, 5) product update.Probability of Precipitation(Abbrev. PoP)- The probability that precipitation will be reported at a certain location during a specified period of time.
Quantitative Precipitation Estimate (QPE)A spatial and temporal analysis estimating the amount of precipitation that has occurred using a variety of techniques including observational and remote sensing data.Quantitative Precipitation ForecastA spatial and temporal precipitation forecast that will predict the potential amount of future precipitation for a specified region, or area.Storm Total PrecipitationThis radar image is an estimate of accumulated rainfall since the last time there was a one-hour, or more, break in precipitation. It is used to locate flood potential over urban or rural areas, estimate total basin runoff and provide rainfall accumulations for the duration of the event and is available only for the short range (out to 124 nm). To determine accumulated precipitation at greater distances you should link to an adjacent radar. Weighing-Type Precipitation GageA rain gage that weighs the rain or snow which falls into a bucket set on a platform of a spring or lever balance. The increasing weight of its contents plus the bucket are recorded on a chart. The record thus shows the accumulation of precipitation.
You can either type in the word you are looking for in the box below or browse by letter. Search: Browse by letter: # A B C D E F G H I J K L M N O P Q R S T U V W X Y Z |
|
weather.gov 
RSS Feeds
