Supercell seen by GOES super rapid scan mode

By Dan Bikos (CIRA), Dan Lindsey (NOAA) and Scott Bachmeier (CIMSS)

Between 18 May–12 June, 2015 GOES-14 imager was in super rapid scan operations for GOES-R (SRSOR) mode. This special mode allows for 1-minute temporal imagery for GOES, similar to what will be available when GOES-R becomes available in 2016.

Download animation, GOES-14, 19 May 20:00 UTC to 20 May 01:26 UTC

During that period a long-lived supercell was seen over west Texas. Thunderstorms began to develop across west Texas during the afternoon of 19 May, along and ahead of an eastward-moving dryline. One of the storms went on to produce a few brief tornadoes, and hail as large as 7cm in diameter.

The development and progress of these systems can be very clearly seen on the GOES-14 super rapid scan loop from 19 May 20:00 UTC to 20 May 01:26 UTC. Looking at southwest Texas along the dryline, it can be seen that the convective initiation occured in two areas (a northern area and southern area), along the dryline.

The northern area continued to show the earlier trend — soon after development the storms dissipated, then another storm developed and followed the same fate. Meanwhile, the storm to the south quickly expanded and intensified. There were multiple reports of tornadoes associated with it.

Cumulus streets just southeast of this storm indicated an unstable air mass that was feeding into this storm. The imagery shows that there was also a nearly east-west oriented line of cumulus on the western flank of the storm, which appeared to be a pre-existing convergence line that was augmented by the flanking line of the storm itself. The northern storm eventually died off around 21:30 UTC. Earlier storms had struggled to persist in that region and the larger storm to the south may have completely cut off the inflow into the northern storm.

The major storm in southwest Texas continued to exhibit numerous characteristics of a severe storm — overshooting top, back-sheared anvil, crisp edge to the anvil cirrus, flanking line with enhanced cumulus and unstable air (cumulus streets) feeding into the storm.

Also on the imagery it can be seen that a weaker storm developed near the Mexican border and moved north. For a while the pulsing updraft with that storm can be followed underneath the anvil cirrus of the dominant storm. It appeared to move just east of the main updraft of the more intense storm. One report of large hail was seen around the time the storms merged.

Additional content

GOES-14 SRSOR 1-minute visible imagery for 19 May 2015 over Texas (GOES-R Proving Ground Blog)
Severe thunderstorm over West Texas, as viewed from 3 GOES satellites (CIMSS Blog)
NOAA Storm Predicton Centre Report
Time Lapse of a tornado producing supercell near Sheffield,Texas, 19 May, 2015 (YouTube)