The GWCC home page contains a four-panel graphic containing satellite and radar observations and a severe weather outlook (all from NOAA). The following is a brief overview of these graphics (organized by column from left to right):
Updated 3/17/2018
- GOES-16 (or GOES-East) Geo-Color Satellite Imagery (upper left) – This image, obtained by the GOES-16 (Geostationary Operational Environmental Satellite) imager provides as close an approximation to daytime True Color imagery as is possible, and thus allows for an intuitive interpretation of meteorological and surface-based features. At night, instead of being dark like in other visible bands, an IR-based multispectral product is provided that differentiates between low liquid water clouds and higher ice clouds. A static city lights database derived from the VIIRS Day Night Band is provided as the nighttime background for geo-referencing. The 5-min imagery is mapped into a 1.5 km Mercator grid over the Continental U.S. for AWIPS. Note, that GOES-East satellite images on different web pages (or in different GWCC posts) may use different enhancement or “false color” image temperature scales. Colorized images, such as these, should always have their own color key. (credit: CIRA)
- GOES-16 (or GOES-East) Upper-Level Water Vapor Satellite Imagery (lower left) – This geostationary satellite imagery also measures “heat,” but the satellite sensors used are more sensitive to the amount and distribution of atmospheric water vapor. When the atmosphere at the middle and high altitudes is dry, infrared energy from lower altitudes (where temperatures are normally warmer) is able to escape to space and be detected by the GOES-16 (Geostationary Operational Environmental Satellite) sensors. GOES-16 Upper-Level Water Vapor Satellite Imagery is used for upper-level tropospheric water vapor tracking, jet stream identification, hurricane track forecasting, mid-latitude storm forecasting, severe weather analysis, upper mid-level moisture estimation (for legacy vertical moisture profiles) and turbulence detection.
- GOES-16 (or GOES-East) Lower-Level Water Vapor Satellite Imagery (lower right) – This geostationary satellite imagery also measures “heat,” but the satellite sensors used are more sensitive to the amount and distribution of atmospheric water vapor. When the atmosphere at the middle and high altitudes is dry, infrared energy from lower altitudes (where temperatures are normally warmer) is able to escape to space and be detected by the GOES-16 (Geostationary Operational Environmental Satellite) sensors. GOES-16 Lower-Level Water Vapor Satellite Imagery is used for detecting water vapor at middle to lower portions of the atmosphere, in addition to high clouds.
- National radar composite image (lower right) – This image brings together radar reflectivity data from some 100 plus radar sites throughout the contiguous 48 states. Radars measure how much energy atmospheric solids and liquids (hydrometeors such as snow, hail, and rain, as well as particles such as dense smoke and volcanic ash) reflect back to a radar site. The greater the reflectivity value (shown in dBz units), the greater the concentration of so-called “hydrometeors,” solids and other objects (e.g., birds, bats), the radar beam may intercept. The color scale ranges from blues and greens (the lowest reflectivities) to reds and purples (the highest reflectivities).
Updated 3/17/2018
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