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Lifted Index Derived from the GOES Sounders

The lifted index (LI) as derived from the GOES-East and GOES-West Sounders is shown in the above images. The LI product displayed is an atmospheric stability parameter which estimates the tendency of a low-level parcel of air (lowest 100 hPa) to continue to rise if it was 'lifted' to the middle of the atmosphere (500 hPa). The units are in degrees Celcius. A negative value indicates an unstable air mass, while a positive value implies a stable air mass. The value is color-coded with reds and yellows being the most unstable and blues and beiges more stable; clouds are represented as a gray color. (See the color bar at the bottom of the images. The right-hand edge of each number matches the color directly beneath it. For example, the brightest yellow corresponds to an LI of -7C; while the brightest red, to -8C.) A time sequence of the images is the best way to monitor stability trends.

The effective resolution of these images is 10 km. Nominal GOES Sounder field-of-view (fov) is 10 km at the satellite sub-point. The full physical retrieval algorithm was used to derive this product.

Entire conterminous US with Radiosondes

The images shown in the product labeled "Entire conterminous US with Radiosondes" are the most recent 00 UT GOES LI DPI, displayed with the corresponding 00 UTC radiosonde values of the lifted index stability parameter (in deg-C) and 300 mb wind flags. The winds have been included to show the upper level flow pattern; upward vertical motions, favorable for convective development, are often associated with the left front and right rear quadrants of upper level jets (or wind maxima). This comparison is typically updated around 05 UTC.

Comparison with reported severe weather

The last LI product available displays preliminary severe weather reports plotted over a representative GOES Sounder LI DPI from yesterday afternoon (22 UTC). The severe weather reports are over the last 24 hours (12 UTC yesterday to 12 UTC today) and are obtained from the Storm Prediction Center. This combination provides a simple, quick look at the level of correlation that exists between the GOES derived atmospheric stability field and subsequent severe weather.