A potent shortwave trough helped to bring severe storms to the southern plains on 30 April 2019 (Fig 1).
The GOES-16 10.3 um – 12.3 um split window channel (SWD) difference, as discussed in previous blog posts (first introduced here), can be utilized to highlight low level moisture features from the clear sky. In this case, dry southwest flow (darker gray) can be visualized mixing out the low level moisture (lighter gray) from west to east across southeast New Mexico and southwest/west Texas (Fig 2). Surface obs confirm the progression of the dry line and gusty southwest winds, with dew points in the mid 50s quickly decreasing to into the 20s. Cumulus clouds were observed developing in the moist air just ahead of and along the boundary, with some areas initiating and developing into severe thunderstorms. In such a case, the SWD can be used as a high resolution source to track evolving gradients in low level moisture (often a dry line), filling gaps between surface observations/analyses. The SWD can also be used to detect lofted dust, the black to brown colors found in Mexico in this animation.
The southernmost thunderstorm developing along the dry line produced hail to 3 inches in diameter, or teacup sized (Fig 3-5). This storm developed an impressive and persistent overshooting top and above anvil cirrus plume. As mentioned in previous posts, the AACP is often associated with severe storms (Bedka, 2018) .
Taking a quick look further north, GOES-16 5-min GLM Flash Extent Density total lightning data shows widespread thunderstorm activity, highlighting the most intense storm cores.
Bill Line, NWS