(Abbrev. PDO) - a recently described pattern of climate variation similar to ENSO though on a timescale of decades and not seasons. It is characterized by SST anomalies of one sign in the north-central Pacific and SST anomalies of another sign to the north and east near the Aleutians and the Gulf of Alaska. It primarily affects weather patterns and sea surface temperatures in the Pacific Northwest, Alaska, and northern Pacific Islands.
- Browse Related Terms: AO, Arctic Oscillation, El Niño, INTSFY, La Niña, NAO Index, NEG, Negative-tilt Trough, NW, Oscillation, Pacific Decadal Oscillation, PDO, Positive-tilt Trough, Southern Oscillation
(Abbrev. PDSI) - an index used to gage the severity of drought conditions by using a water balance equation to track water supply and demand. This index is calculated weekly by the National Weather Service.
Also listed in:
A headline within National Weather Service high seas forecasts transmitted via the GMDSS to indicate that a hurricane or hurricane force winds are forecast.
- Browse Related Terms: 88D, AMVER/SEAS, Congressional Organic Act of 1890, NAVTEX Forecast, NOAA Weather Radio, NWR, NWSH, Pan Pan, S-Band Radar, Securite, SIGWX, Wind Waves, WX
Low pressure systems that originate in the panhandle region of Texas and Oklahoma which initially move east and then "hook" or recurve more northeast toward the upper Midwest or Great Lakes region. In winter, these systems usually deposit heavy snows north of their surface track. Thunderstorms may be found south of the track.
- Browse Related Terms: Azimuth Angle, BNDRY, E, Gulf Stream, International Date Line, NE, North Wall, ORIG, Panhandle Hook, PNHDL, Subtle Heavy Rainfall Signature, Texas Hooker, West Wall
A subset of the group of evaluations that constitute each element of an observation.
- Browse Related Terms: AMOS, Blowing, Cooperative Observer, GoMoos, Hourly Precipitation Data (HPD), Isochrone, Mesonet, Meteogram, Nadir, OBS, parameter, Rawinsonde Observation, Reconnaissance Code, report, Station Model, Upper Level
Also listed in:
The scientific name for sun dogs. Either of two colored luminous spots that appear at roughly 22 degrees on both sides of the sun at the same elevation. They are caused by the refraction of sunlight passing through ice crystals. They are most commonly seen during winter in the middle latitudes and are exclusively associated with cirriform clouds. They are also known as mock suns.
- Browse Related Terms: Anthelion, Aphelion, apogee, Crepuscular Rays, disk, Halo, Parhelion, Perigee, Perihelion, Photosphere, Rainbow, Right Ascension, Sun Pillar, Tidal Cycle, Tide Prediction, Undersun, Year
A limitation of the rainfall estimation techniques used by NEXRAD. At far ranges from the radar, a storm may occupy only a portion of the radar beam (which may be several miles across). However, the radiation received by the radar antenna consists of the average reflectivity across the entire beam, so the reflectivity and associated rainfall rates are underestimated.
- Browse Related Terms: Hail Contamination, Hail Spike, Inch-Degrees, Partial Beam Filling, POH, Precipitation Mode, Probability of Hail, Radar Data Acquisition, Radar Mosaic, Radar Product Generator (RPG), Rainfall Estimates, SHARS, Storm Total Precipitation
Between 3/8 and 5/8 of the sky is covered by clouds. The term "Partly Sunny" is used only during daylight hours.
- Browse Related Terms: AURORA, Broken Level, Cloudy, Convective Overdevelopment, Fair, Jet Stream Cirrus, Mostly Clear, Mostly Cloudy, Mostly Sunny, Okta, Opaque, Partly Cloudy, Partly Sunny, RPD, Shallow Fog, Shower, Sky Condition, Sunny
- Browse Related Terms: Bow Echo, Comma Echo, Enhanced V, Hook Echo, Inflow Bands, LEWP, Line Echo Wave Pattern, Overrunning, Pat, Pre-Hurricane Squall Line, PTTN, Thin Line Echo
Also listed in:
PC-Gridded Interactive Display and Diagnostic System - Allows the forecaster to view fields of gridded model output in contour or vector format. By doing this, the forecaster can extract relevant information from the numerical model grid-point data.
- Browse Related Terms: AVN, CDB, ECMWF, ENSEMBLE, ETA, Eta Model, Forecast Guidance, GFS, Global Forecast System, GRIB, MRF, NGM, NMRS, NOGAPS, PC-GRIDDS, QPFERD, QPFHSD, RUC, UKMET, WAVEWATCH III