By Scott Bachmeier •1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images before sunset (above) and Infrared images after sunset (below) revealed Above-Anvil Cirrus Plume (AACP) features associated with severe thunderstorms that were producing large hail (SPC storm reports) over the Texas Panhandle on 22 March 2019. A plot of 00 UTC rawinsonde data from Amarillo, Texas (below) showed that the Equilibrium Level (EL) and the tropopause was around 11 km — where the air temperature was near -60ºC, which is highlighted by a red enhancement on the Infrared imagery. The calculated Maximum Parcel Level was around 13 km — where the air temperature was near -50ºC, which is highlighted by a yellow enhancement on the Infrared imagery; the MPL was the likely altitude of the AACP. Note on the 0245 UTC and 0258 UTC images that two of the hail reports were located near the colder (darker red to black) pixels of overshooting tops, which were close to the southern end of the warmer (brighter yellow) pixels of the AACP. As pointed out on the Satellite Liaison Blog, some of the accumulating hail remained on the ground during the overnight hours — and the next morning, a hail swath signature was evident on GOES-16 Visible and Near-Infrared “Snow/Ice” (1.61 µm) imagery (below); the longest swath stretched for a distance of about 40 miles. The hail appeared as shades of white in the Visible imagery, and as darker shades of black in the Snow/Ice imagery (since ice is a strong absorber of radiation at the 1.61 µm wavelength). Note how the darker signature of wet soil (water is also a strong absorber at 1.61 µm) persisted on Near-Infrared imagery even after the brighter signature of the melting hail swath disappeared on Visible imagery. Accumulating hail occurred over portions of Interstate 27 between Amarillo and Canyon, and Interstate 40 between Wildorado and Bushland; one trained storm spotter reported that the hail was several inches deep just northwest of Amarillo (Local Storm Reports). As the morning sun was beginning to warm the soil, GOES-16 Land Surface Temperature images at 1402 and 1502 UTC or 9:02 and 10:02 AM local time (below) depicted temperatures up to 10ºF cooler within the hail swath compared to adjacent bare ground. With ample illumination from the Moon (in the Waning Gibbous phase, at 92% of Full) a “visible image at night” was provided by the Suomi NPP VIIRS Day/Night Band (0.7 µm), which showed the hall swath at 0748 UTC or 2:48 AM local time — a toggle between that Day/Night Band image and an early morning GOES-16 Visible image is shown bellow.
Categories: GOES-16, Severe convection, Suomi NPP, VIIRS