Meteorology and atmospheric science terminology · MLC-0110

Meteorology and atmospheric science terms: P (219)

PACPacific
Pacific Decadal Oscillation(Abbrev. PDO) - a recently described pattern of climate variation similar to ENSO though on a timescale of...
Palmer drought severity index(Abbrev. PDSI) - an index used to gage the severity of drought conditions by using a water balance equation...
Pan PanA headline within National Weather Service high seas forecasts transmitted via the GMDSS to indicate that a...
pancake iceIn hydrologic terms, circular flat pieces of ice with a raised rim; the shape and rim are due to repeated...
Panhandle HookLow pressure systems that originate in the panhandle region of Texas and Oklahoma which initially move east...
parameterA subset of the group of evaluations that constitute each element of an observation.
Parapet WallIn hydrologic terms, a solid wall built along the top of the dam for ornament, safety, or to prevent...
parcelA volume of air small enough to contain uniform distribution of its meteorological properties and large...
parhelionThe scientific name for sun dogs. Either of two colored luminous spots that appear at roughly 22 degrees on...
Partial Beam FillingA limitation of the rainfall estimation techniques used by NEXRAD. At far ranges from the radar, a storm may...
Partial-Duration Flood SeriesIn hydrologic terms, a list of all flood peaks that exceed a chosen base stage or discharge, regardless of...
Particle Trajectory ModelA computer sub-model that tracks the trajectories of multiple particles that are released into an atmospheric...
partly cloudyBetween 3/8 and 5/8 of the sky is covered by clouds.
Partly SunnyBetween 3/8 and 5/8 of the sky is covered by clouds. The term "Partly Sunny" is used only during daylight...
pascalThe unit of pressure produced when one newton acts on one square meter (1 N/m^2). It is abbreviated Pa.
PATPattern
PBLProbable
PC-GRIDDSPC-Gridded Interactive Display and Diagnostic System - Allows the forecaster to view fields of gridded model...
PCPNPrecipitation
PCTprecent
PDPeriod
PDIPalmer Drought Index
PDMTPredominant
PDOPacific Decadal Oscillation - a recently described pattern of climate variation similar to ENSO though on a...
PDSParticularly Dangerous Situation (PDS) wording is used in rare situations when long-lived, strong and violent...
PDS WatchThe Particularly Dangerous Situation (PDS) wording is used in rare situations when long-lived, strong and...
PDSIPalmer Drought Severity Index - an index used to gage the severity of drought conditions by using a water...
PDTPacific Daylight Time
peak dischargeIn hydrologic terms, the rate of discharge of a volume of water passing a given location
Peak Flow Arrival TimeThe time at which a stream reach is forecast to achieve its maximum flow within the forecast period.
peak gustThe highest instantaneous wind speed observed or recorded.
Peak PulseThe amount of power transmitted by a radar during a given pulse. Note that because these pulses are widely...
Peak Wind SpeedThe maximum instantaneous wind speed since the last observation that exceeded 25 knots.
Pendant EchoRadar signature generally similar to a hook echo, except that the hook shape is not as well defined.
Penetrating TopSame as Overshooting Top; a dome-like protrusion above a thunderstorm anvil, representing a very strong...
PenumbraIn solar-terrestrial terms, the sunspot area that may surround the darker umbra or umbrae. It consists of...
perched groundwaterIn hydrologic terms, local saturated zones above the water table which exist above an impervious layer of...
percolationIn hydrologic terms, the movement of water, under hydrostatic pressure, through the interstices of a rock or...
Percolation PathIn hydrologic terms, the course followed by water moving or percolating through any other permeable material...
perennial streamIn hydrologic terms, a stream that flows all year round.
perigeeThe closest distance between moon and earth or the earth and sun.
perihelionThe point on the annual orbit of a body (about the sun) that is closest to the sun; at present, the earth...
permafrostA layer of soil at varying depths below the surface in which the temperature has remained below freezing...
permeabilityIn hydrologic terms, the ability of a material to transmit fluid through its pores when subjected to a...
Permeability CoefficientIn hydrologic terms, the rate of flow of a fluid through a cross section of a porous mass under a unit...
permeameterIn hydrologic terms, a laboratory instrument for determining permeability by measuring the discharge through...
persistenceContinuation of existing conditions. When a physical parameter varies slowly, the best prediction is often...
persistence forecastA forecast that the current weather condition will persist and that future weather will be the same as the...
Perturbation ModelA computer model used to calculate air pollution concentrations. A perturbation model produces a wind field...
Pervious ZoneIn hydrologic terms, a part of the cross section of an embankment dam comprising material of high permeability
PFDQPF Discussion (issued by the HPC)
Phenomenological ModelA computer model used to calculate air pollution concentrations. A phenomenological model focuses on an...
PHFOHonolulu National Weather Service Forecast Office
PhiezometerIn hydrologic terms, an instrument used to measure pressure head in a conduit, tank, soil, etc. They are used...
photochemical smogAir pollution containing ozone and other reactive chemical compounds formed by the reaction of nitrogen...
photosphereThe intensely bright portion of the sun visible to the unaided eye; the "surface" of the sun. Reaching...
phreatic waterIn hydrologic terms, water within the earth that supplies wells and springs; water in the zone of saturation...
pibalPilot balloon. A small helium-filled meteorological balloon that is tracked as it rises through the...
pilot balloon(Abbrev. PIBAL)- A small helium-filled meteorological balloon that is tracked as it rises through the...
pilot report(Abbrev. PIREP)- A report of inflight weather by an aircraft pilot or crew member. A complete coded report...
pingoA large frost mound of more than one-year duration.
PIREPPilot Report. A report of inflight weather by an aircraft pilot or crew member. A complete coded report...
Pitot tubeIn hydrologic terms, a device for measuring the velocity of flowing water using the velocity head of the...
PIXpicture
PKPeak
PL1. Ice pellets (sleet)
PlageIn solar-terrestrial terms, an extended emission feature of an active region that exists from the emergence...
Plage CorridorIn solar-terrestrial terms, a space in chromospheric plage lacking plage intensity, coinciding with polarity...
PlagenilIn solar-terrestrial terms, spotless disc free of calcium plage.
plan position indicatorAn acronym for Plan Position Indicator. A PPI displays radar data horizontally using a map projection. In PPI...
Planetary Boundary LayerThe layer within the atmosphere between 1 km and the earth's surface where friction affects wind speed and...
plasmaAny ionized gas; that is, any gas containing ions and electrons.
PlatformA generic radar term, often used to encompass the pedestal and antenna assembly; sometimes including the...
plow windA term used in the midwestern United States to describe strong, straight-line winds associated with the...
Plume BlightVisibility impairment caused by air pollution plumes aggregated from individual sources.
Plume ImpingementThe collision of a plume with topography that rises above the plume altitude; often a temporary condition...
Plume-dominated FireA fire whose behavior is governed primarily by the local wind circulation produced in response to the strong...
pluvialIn hydrology, anything that is brought about directly by precipitation.
PMDPrognostic Discussion
PMOPort Meteorological Officer.
PNAPacific North American teleconnection
PNHDLPanhandle
PNSPublic Information Statement - a narrative statement issued by a National Weather Service Forecast Office...
POHProbability of Hail - a product from the NEXRAD hail detection algorithm that estimates the likelihood that...
point precipitationPrecipitation at a particular site, in contrast to the mean precipitation over an area.
point sourceA pollutant source that can be treated in a dispersion model as though pollutants were emitted from a single...
Polar Cap AbsorptionIn solar-terrestrial terms, an anomalous condition of the polar ionosphere whereby HF and VHF (3 - 300 MHz)...
polar frontA semipermanent, semicontinuous front that separates tropical air masses from polar air masses.
Polar JetMarked by a concentration of isotherms and strong vertical shear, this jet is the boundary between the polar...
Polar Jet StreamUsed interchangably with Polar Jet; a jet stream marked by a concentration of isotherms and strong vertical...
Polarization RadarA radar which takes advantage of ways in which the transmitted waves' polarization affect the backscattering...
polar-orbiting satelliteA weather satellite which travels over both poles each time it orbits the Earth. It orbits about 530 miles...
PollutantParticles, gases, or liquid aerosols in the atmosphere which have an undesirable effect on humans or their...
pondageIn hydrologic terms, (1) The holding back of water for later release for power development above the dam of a...
PondingIn hydrologic terms, in flat areas, runoff collects, or ponds in depression and cannot drain out. Flood...
PoolThe elevation of the surface of a body of water such as a lake. Specifically, the pool at a lock and dam or a...
Pool HeightIn hydrologic terms, the height of the water behind a dam. (Various datums may be used and various pool...
POPProbability of Precipitation
Popcorn ConvectionSlang for showers and thunderstorms that form on a scattered basis with little or no apparent organization...
POPSProbability of Precipitation
porosityIn hydrologic terms, (1) The ratio of pore volume to total volume of the formation. Sandy soils have large...
POSPositive
Positive AreaThe area on a sounding representing the layer in which a lifted parcel would be warmer than the environment...
positive cloud-to-ground lightningA CG flash that delivers positive charge to the ground, as opposed to the more common negative charge...
Positive Vorticity Advection(Abbrev. PVA) - Advection of higher values of vorticity into an area, which often is associated with upward...
Positive-tilt TroughAn upper level system which is tilted to the east with increasing latitude (i.e., from southwest to...
Post-Flare LoopsIn solar-terrestrial terms, a loop prominence system often seen after a major two-ribbon flare, which bridges...
Post-storm ReportA report issued by a local National Weather Service office summarizing the impact of a tropical cyclone on...
potential temperatureThe temperature a parcel of dry air would have if brought adiabatically (i.e., without transfer of heat or...
potential vorticityThis plays an important role in the generation of vorticity in cyclogenesis, especially along the polar...
powder snowDry, loose, unconsolidated snow.
powerA radar equation to describe the amount of power that a radar emits.
PPIPlan Position Indicator
PPINEPlan Position Indicates No Echoes, referring to the fact that a radar detects no precipitation within its...
PQPFProbabilistic QPF; a form of QPF (see below) that includes an assigned probability of occurrence for each...
PRBLTYProbability
PRBLYprobably
PRCPPrecipitation
PRECDPrecede
precipitable waterMeasure of the depth of liquid water at the surface that would result after precipitating all of the water...
precipitationThe process where water vapor condenses in the atmosphere to form water droplets that fall to the Earth as...
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 Processing SystemThe WSR-88D system that generates 1-hour running, 3-hourly, and running storm total precipitation...
precisionThe accuracy with which a number can be represented, i.e., the number of digits used to represent a number.
Predominant WindThe wind that prevails and generates the local component of the significant sea conditions across the...
Pre-Frontal Squall LineA line of thunderstorms that precedes an advancing cold front.
Pre-Frontal TroughAn elongated area of relatively low pressure preceding a cold front that is usually associated with a shift...
Pre-Hurricane Squall LineIt is often the first serious indication that a hurricane is approaching. It is a generally a straight line...
Preliminary ReportNow known as the "Tropical Cyclone Report". A report summarizing the life history and effects of an Atlantic...
PRESPressure
Prescribed FireA management ignited or natural wildland fire that burns under specified conditions where the fire is...
Present MovementThe best estimate of the movement of the center of a tropical cyclone at a given time and given position...
Present WeatherThe type of weather observed at the reporting time. These conditions may include types and intensity of...
pressureThe exertion of force upon a surface by a fluid (e.g., the atmosphere) in contact with it.
pressure altimeterAn aneroid barometer calibrated to indicate altitude in feet instead of units of pressure. It is read...
pressure altitudeThe altitude in standard atmosphere at which a given pressure will be observed. It is the indicated altitude...
Pressure ChangeThe net difference between the barometric pressure at the beginning and ending of a specified interval of...
Pressure CharacteristicThe pattern of the pressure change during the specified period of time, usually the three hour period...
Pressure CoupletIt is an area where you have a high pressure area located adjacent to a low pressure area.
Pressure Falling RapidlyA decrease in station pressure at a rate of 0.06 inch of mercury or more per hour which totals 0.02 inch or...
Pressure GageA device for registering the pressure of solids, liquids, or gases. It may be graduated to register pressure...
pressure gradientThe amount of pressure change occurring over a given distance.
Pressure Gradient ForceA three-dimensional force vector operating in the atmosphere that accelerates air parcels away from regions...
pressure headEnergy contained by fluid because of its pressure, usually expressed in feet of fluid (foot pounds per pound).
pressure iceFloating sea, river, or lake ice that has been deformed, altered, or forced upward in pressure ridges by the...
Pressure Induced WaveA rare type of wave that does not develop from wind or seismic activity. Instead, these waves develop as a...
pressure jumpA sudden, sharp increase in atmospheric pressure, typically occurring along an active front and preceding a...
Pressure Rising RapidlyAn increase in station pressure at a rate of 0.06 inch of mercury or more per hour which totals 0.02 inch or...
pressure tendencyThe character and amount of atmospheric pressure change during a specified period of time, usually 3-hour...
Pressure UnsteadyA pressure that fluctuates by 0.03 inch of mercury or more from the mean pressure during the period of...
Pressure-driven ChannelingChanneling of wind in a valley by synoptic-scale pressure gradients superimposed along the valley's axis...
prevailing visibilityThe visibility that is considered representative of conditions at the station; the greatest distance that can...
Prevailing WesterliesThe westerly winds that dominant in middle latitudes.
Prevailing WindsA wind that consistently blows from one direction more than from any other.
Prevention of Significant DeteriorationA program, specified in the Clean Air Act, whose goal is to prevent air quality from deteriorating...
PRIMPrimary
Primary Ambient Air Quality StandardsAir quality standards designed to protect human health.
Primary Control Tide StationA tide station where continuous observations have been made for a minimum of 19 years. Its purpose is to...
Primary PollutantSubstances that are pollutants immediately on entering the atmosphere. Compare secondary pollutant.
Primary Swell DirectionPrevailing direction of swell propagation.
PRINPrincipal
probabilityA chance, or likelihood, that a certain event might happen.
probability forecastA forecast of the probability that one or more of a mutually exclusive set of weather conditions will occur.
Probability of Hail(Abbrev. POH) - a product from the NEXRAD hail detection algorithm that estimates the likelihood that hail is...
Probability of precipitation(Abbrev. PoP)- The probability that precipitation will be reported at a certain location during a specified...
Probability of ThunderstormsThe probability based on climatology that a thunderstorm will be reported at that location during a specified...
Probability of Tropical Cyclone ConditioThe probability, in percent, that the cyclone center will pass within 50 miles to the right or 75 miles to...
Product ResolutionThe smallest spatial increment or data element that is distinguishable in a given Doppler radar product.
profilerAn instrument designed to measure horizontal winds directly above its location, and thus measure the vertical...
progForecast (prognostication)
PROGGEDForecasted
Prognostic DiscussionThis Hydrometeorological Prediction Center (HPC) discussion may include analysis of numerical and statistical...
Progressive DerechoDerecho characterized by a short curved squall line oriented nearly perpendicular to the mean wind direction...
ProminenceA term identifying cloud-like features in the solar atmosphere. The features appear as bright structures in...
PROPAPropagation (movement)
Propagation1. The movement of an atmospheric phenomenon. This term is frequently applied to the motion of thunderstorms...
Property ProtectionMeasures that are undertaken usually by property owners in order to prevent, or reduce flood damage. Property...
protonSolar activity levels with at least one high energy event (Class X Flares).
Proton EventIn solar-terrestrial terms, the measurement of at least 10 protons/cm^2/sec/steradian at energies greater...
Proton FlareIn solar-terrestrial terms, any flare producing significant fluxes of greater-than-10 MeV protons in the...
PRSTPersist
PRVDProvide
PSBLPossible
PSBLYpossibly
Pseudo-Cold FrontA boundary between a supercell's inflow region and the rear-flank downdraft (or RFD). It extends outward from...
Pseudo-Warm FrontA boundary between a supercell's inflow region and the forward-flank downdraft (or FFD). It extends outward...
PSGPassage
PSTPacific Standard Time
psychrometerAn instrument used to measure the water vapor content of the air; a hygrometer consisting essentially of two...
PTCHYPatchy
PTCLDYPartly Cloudy
PTDYOn a buoy report, Pressure Tendency is the sign (plus or minus) and the amount of pressure change (hPa) for a...
PTLYPartly
PTNPortion
PTTNpattern
PTWC(Pacific Tsunami Warning Center) - The Pacific Tsunami Warning Center in Ewa Beach (pronounced Eva Beach), HI...
PTYPEprecipitation type
Public Information StatementA narrative statement issued by a National Weather Service Forecast Office that can be used for:
Public Severe Weather OutlookThese are issued when the Storm Prediction Center (SPC) in Norman, Oklahoma anticipates an especially...
PuddleIn hydrologic terms, (1) The act of compacting earth, soil clay, etc., by mixing them with water and rolling...
Puget Sound Convergence ZoneA situation where wind forced around the Olympic Mountains converges over the Puget Sound. Causes extreme...
pulseA short burst of electromagnetic energy that a radar sends out in a straight line to detect a precipitation...
pulse durationThe time over which a radar pulse lasts. The pulse duration can be multiplied by the speed of light to...
pulse lengthThe linear distance in range occupied by an individual pulse from a radar. h = c * t , where t is the...
Pulse RadarA type of radar, designed to facilitate range (distance) measurements, in which are transmitted energy...
pulse repetition frequencyThe amount of time between successive pulses, or bursts, of electromagnetic energy that is transmitted by a...
Pulse Repetition TimeThe time elapsed between pulses by the radar. This is also called the pulse interval.
Pulse Resolution VolumeA discrete radar sampling volume, of dimensions (horizontal beamwidth * vertical beamwidth * 1 range gate).
Pulse Severe ThunderstormsSingle cell thunderstorms which produce brief periods of severe weather (3/4 inch hail, wind gusts in the...
Pulse StormA thunderstorm within which a brief period (pulse) of strong updraft occurs, during and immediately after...
Pulse WidthSame as Pulse Length; the linear distance in range occupied by an individual pulse from a radar. h = c * t ...
pulse-pair processingNickname for the technique of mean velocity estimation by calculation of the signal complex covariance...
PVAPositive Vorticity Advection - the advection of higher values of vorticity into an area.
PVLPrevail
PWPrecipitable Water - measure of the depth of liquid water at the surface that would result after...
PWATPrecipitable Water - measure of the depth of liquid water at the surface that would result after...
PWOPublic Severe Weather Outlook

219 of 3,164 terms in Meteorology and atmospheric science terminology (MLC-0110). Request the full dataset.