In solar-terrestrial terms, a fast radio burst spectrum of a flare. It has a U-shaped appear- ance in an intensity-vs.-frequency plot
- Browse Related Terms: aliasing, ARINC, Centimeter Burst, Extreme Ultraviolet (EUV), Extremely low frequency (ELF), High Frequency (HF), Low Frequency, M 3000, Medium Frequency, Polar Cap Absorption (PCA), PTN, Riometer, U Burst, Ultra High Frequency (UHF), Ver High Frequency (VHF), very low frequency (VLF), Visual Spectrum, White Light (WL)
(Abbrev. USGS)- The Federal Agency chartered in 1879 by congress to classify public lands, and to examine the geologic structure, mineral resources, and products of the national domain. As part of its mission, the USGS provides information and data on the NationÂs rivers and streams that are useful for mitigation of hazards associated with floods and droughts.
- Browse Related Terms: AFWA, Client Agency, FEMA, LCD (Local Climatological Data), National Climatic Data Center, NCAR, NCDC, NDBC, NOAA, NWS, OEODM, U.S. Geological Survey, WC/ATWC
(Unit Control Position): The WSR-88D radar operator uses this to control the entire radar system. One of the main things that the radar operator will do at the UCP is change volume scan strategies of the antenna. These volume scan strategies tell the radar how many elevation angles will be used during a single volume scan (a volume scan is the completion of a sequence of elevation angles), and the amount of time it will take to complete that sequence of elevation cuts, each one being a single rotation of the antenna's 1 degree beam at selected elevation angles. The WSR-88D uses 3 scan strategies. They are the following: 14 elevation angles in 5 minutes (this is used during severe weather situations), 9 elevation angles in 6 minutes (this is used when there is precipitation within 248 nautical miles of the radar), and 5 elevation angles in 10 minutes (this is used when there is no precipitation within 248 nautical miles). The radar operator at the UCP can also adjust the radar products and help the users out with their communication problems.
- Browse Related Terms: Echo Tops, ENTR, Plan Position Indicator, PPINE, Range Height Indicator, RELBL, Sectorized Hybrid Scan, UCP, Unit Control Position, VCP, Volume Scan
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(Universal Geographic Code) - (e.g. ANZ300 for Western Long Island Sound) are used in many National Weather Service text products to provide geographical information. This allows users easy automated processing and redistribution of the information. More specifically, the purpose of the UGC are to specify the affected geographic area of the event, typically by state, county (or parish), or unique NWS zone (land and marine). The only exception to the above is to define the weather synopsis part of certain marine products.
- Browse Related Terms: AFOS, AFSS, SYNS, UGC, Universal Geographic Code, Valid Time Event Code, VTEC
A medium-range (3 to 7 day) numerical weather prediction model operated by the U nited K ingdom MET eorological Agency. It has a resolution of 75 kilometers and covers the entire northern hemisphere. Forecasters use this model along with the ECMWF and GFS in making their extended forecasts (3 to 7 days).
- 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
Upper Level Jet
- Browse Related Terms: AGL, ASL, Explosive Deepening, Gamma-Ray, Jet stream, JSTR, LVL, LVLS, Mesopause, MSLP, Rapid Deepening, SL, SLP, Storm Surge, TIDE, ULJ, Unsettled
Those radio frequencies exceeding 300 MHz
- Browse Related Terms: aliasing, ARINC, Centimeter Burst, Extreme Ultraviolet (EUV), Extremely low frequency (ELF), High Frequency (HF), Low Frequency, M 3000, Medium Frequency, Polar Cap Absorption (PCA), PTN, Riometer, U Burst, Ultra High Frequency (UHF), Ver High Frequency (VHF), very low frequency (VLF), Visual Spectrum, White Light (WL)
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This index provides important information to help you plan your outdoor activities in ways that prevent overexposure to the sun's rays. It was designed by the National Weather Service (NWS) and the Environmental Protection Agency (EPA). Unlike some countries' indices, the United States UV Index is not based upon surface observations. Rather, it is computed using forecasted ozone levels, a computer model that relates ozone levels to UV incidence on the ground, forecasted cloud amounts, and the elevation of the forecast cities. The calculation starts with measurements of current total ozone amounts for the entire globe, obtained via two satellites operated by the National Oceanic and Atmospheric Administration (NOAA). These data are then used to produce a forecast of ozone levels for the next day at various points around the country.
Category UV Index Time to Burn Actions to Take Minimal 0 - 2 60 min. + Apply SPF sunscreen. Low 3 - 4 45 min. Apply SPF sunscreen, wear a hat. Moderate 5 - 6 30 min. Apply SPF 15, wear a hat. High 7 - 9 15 - 24 min. Apply SPF 15 to 30, wear a hat and sunglasses. Limit midday exposure. Very High 10+ 10 min. Apply SPF 30; wear a hat, sunglasses, and protective clothing; limit midday exposure. - Browse Related Terms: EPA, HMD, National Fire Danger Rating System, SOLN, SOLNS, Ultraviolet Index, UV Index
Electromagnetic radiation of shorter wavelength than visible radiation but longer than x-rays.
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In solar-terrestrial terms, the dark core or cores (umbrae) in a sunspot with penumbra, or a sunspot lacking penumbra.
- Browse Related Terms: Arch Filament System (AFS), Coronal Rain, CRN, fibril, Light Bridge, MDFY, Penumbra, Plage Corridor, Solar Maximum, Solar Minimum, Sunspot Number, surge, Umbra, Zurich Sunspot Classification
In hydrologic terms, a current below the upper currents or surface of a fluid body.
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The lateral motion of water through the upper layers until it enters a stream channel. This usually takes longer to reach stream channels than runoff. This also called subsurface storm flow.
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An optical effect seen by an observer above a cloud deck when looking toward the sun, as sunlight is reflected upwards off the faces of ice crystals in the cloud deck. [Also known as subsun.]
- 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 relatively small-scale surf-zone current moving away from the beach. Rip currents form as waves disperse along the beach causing water to become trapped between the beach and a sandbar or other underwater feature. The water converges into a narrow, river-like channel moving away from the shore at high speed.
- Browse Related Terms: channel, Channelization, DNR, DPNG, Dredging, Rip Current, Undertow
A distribution having only one localized maximum, i.e., only one peak.
- Browse Related Terms: g, Gust, Kts, MAX, Peak Wind Speed, PK, Rain Shield, Squall, Turbulence, Unimodal, Variable Wind, Variable Wind Direction, Wind Gust, Wind Shift, Wind Speed
The WSR-88D radar operator uses this to control the entire radar system. One of the main things that the radar operator will do at the UCP is change volume scan strategies of the antenna. These volume scan strategies tell the radar how many elevation angles will be used during a single volume scan (a volume scan is the completion of a sequence of elevation angles), and the amount of time it will take to complete that sequence of elevation cuts, each one being a single rotation of the antenna's 1 degree beam at selected elevation angles. The WSR-88D uses 3 scan strategies. They are the following: 14 elevation angles in 5 minutes (this is used during severe weather situations), 9 elevation angles in 6 minutes (this is used when there is precipitation within 248 nautical miles of the radar), and 5 elevation angles in 10 minutes (this is used when there is no precipitation within 248 nautical miles). The radar operator at the UCP can also adjust the radar products and help the users out with their communication problems.
- Browse Related Terms: Echo Tops, ENTR, Plan Position Indicator, PPINE, Range Height Indicator, RELBL, Sectorized Hybrid Scan, UCP, Unit Control Position, VCP, Volume Scan
The discharge hydrograph from one inch of surface runoff distributed uniformly over the entire basin for a given time period
- Browse Related Terms: ADVIS, API Method, Basin, Catchment Area, Depth of Runoff, Drainage area, Drainage Divide, Effective Precipitation, Inches of Runoff, Initial Detention, response time, Unit hydrograph
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(UGC) - UGC's, (e.g. ANZ300 for Western Long Island Sound) are used in many National Weather Service text products to provide geographical information. This allows users easy automated processing and redistribution of the information. More specifically, the purpose of the UGC are to specify the affected geographic area of the event, typically by state, county (or parish), or unique NWS zone (land and marine). The only exception to the above is to define the weather synopsis part of certain marine products.
- Browse Related Terms: AFOS, AFSS, SYNS, UGC, Universal Geographic Code, Valid Time Event Code, VTEC
By international agreement, the local time at the prime meridian, which passes through Greenwich, England. Prior to 1972, this time was called Greenwich Mean Time (GMT) but is now referred to as Coordinated Universal Time or Universal Time Coordinated (UTC). It is a coordinated time scale, maintained by the Bureau International des Poids et Mesures (BIPM). It is also known a "Z time" or "Zulu Time".
More about UTC, and a table to convert UTC to your local time is posted at: http://www.srh.noaa.gov/srh/jetstream/doppler/radarfaq.htm#utc
- Browse Related Terms: Climate Diagnostics Center, Coordinated Universal Time (UTC), GMT, Intermediate Synoptic Times, Main Synoptic Times, MAINT, NAM, Standard Synoptic Times, Universal Time (UT), UTC, Z, Zulu (Z) Time
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Unseasonable
- Browse Related Terms: Bartel's Rotation Number, Colorado Low, Day Length, Excessive Heat Warning, Forecast valid for, Growing Degree Day, Heat Wave, Humidity Recovery, Indian Summer, January Thaw, Night, recurrence, Temperature Recovery, Tropical Cyclone Plan of the Day, Twilight, UNSBL