Digital Base Reflectivity (NXQ, NYQ, NZQ, N0Q, NAQ, N1Q, NBQ, N2Q, N3Q/94) Sixteen possible data levels are also available. Four low elevation angles are available, with specific elevation angles depending on the scanning mode of the Radar. Scientists use these products to detect precipitation, evaluate storm structure, locate boundaries, and determine hail potential. Product Descriptionsīase Reflectivity (N0R, N1R, N2R, N3R/19 and N0Z/20)Ī display of echo intensity measured in decibels relative to Z (dBZ). Note: Missing 元 data for Hurricane Ian were recently reprocessed and restored to archive. Each copy includes state, county, and city background maps. Most 元 products are available as digital images, color hard copy, grayscale hard copy, or acetate overlay copy. Over 75 Level-III (元) products are routinely available from NCEI. A data file consists of a 24-byte volume scan header record followed by numerous 2,432-byte base data and message records. Data are stored in files that typically contain four, five, six, or ten minutes of base data depending on the volume coverage pattern. Additional categories include dual-polarization base data of differential reflectivity, correlation coefficient, and differential phase. Level-II (L2) data are grouped into three meteorological base quantities: reflectivity, mean radial velocity, and spectrum width. Request Offline Data NEXRAD Level-II (Base) Data This dataset is not currently available for direct download from NCEI, but is available by request from the offline archive. An inventory of events is available here. An event summary file with descriptive information is included for each case study. The data files have been aggregated by event and by hour for the archive with a total data volume of approximately 20 TB. The data files are in the native compressed file format as Time Series (TS) Archive. The number of case studies per year ranges from 1 to 33, with an average of approximately 10 per year. The period of record is from 2008 to present with additional data years planned. NEXRAD operational sites and test sites are used. It includes only the Level 1 data that has been used for algorithm development and verification by the ROC and its partners. If the radar animation of the last hours shows local thunderstorms or precipitation cells forming and disappearing in an irregular manner, then the forecast is not vey accurate.This dataset contains the Level-I (L1) raw radar event data recorded at Next Generation Radar (NEXRAD) sites and collected by the NOAA National Weather Service (NWS) Radar Operations Center (ROC) for specific radar case studies. The forecast works very well when weather fronts or large organized precipitation structures are moving regularly, without disappearing or being created. Real weather is more complex than just the displacement of existing precipitation cells. Longer forecasts are not possible, as new precipitation cells are developing or existing ones are disappearing within a short time. This so called precipitation nowcast is the most accurate precipitation forecast possible but the forecast horizon is limited to about an hour. The rain/snow forecast is computed by estimating the movement of precipitation cells observed by radar and extrapolating this movement into the future. United States: How accurate is the radar based forecast? Moreover, some countries do not operate a weather radar network, and in those countries satellite data is used to estimate rainfall, which is less accurate than a realtime weather radar. Note that lightning is not shown on the forecast, as it cannot be predicted. Light blue indicates drizzle, blue a medium intensity, and red and yellow indicate very strong precipitation, usually associated with thunderstorms.Ĭurrent lightning strikes are marked with small orange dots on the map (Europe only). The different colours indicate the intensity of rainfall or snowfall. The radar map is updated every 5 minutes with a new radar observation. The weather radar ( United States) shows where it is currently raining or snowing.
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