GOES-14 SRSO-R: convective outflow boundary in southern Texas

April 20th, 2016 |

GOES-14 Visible (0.63 µm) images [click to play MP4 animation]

GOES-14 Visible (0.63 µm) images [click to play MP4 animation]

1-minute interval SRSO-R GOES-14 Visible (0.63 µm) images (above; also available as a large 259 Mbyte animated GIF) showed a curved outflow boundary — produced by a strong quasi-linear convective system the preceding overnight hours in northern Texas — which continued to propagate southward across southern Texas during the day on 20 April 2016. New clusters of convection formed along and in the wake of the eastern portion of the outflow boundary (which dropped an additional 0.67 inch of rainfall in one hour across the flood-ravaged Houston area), while the western portion was marked by a low-level arc cloud.

On the corresponding GOES-14 Water Vapor (6.5 µm) images (below; also available as a large 126 Mbyte animated GIF), a very subtle signature of the western  part of the outflow boundary could be seen in the dryer atmosphere (where the water vapor weighting functions were shifted to lower altitudes). Also of interest were a few long and narrow contrails which appeared within that same dry region of the atmosphere after about 1800 UTC — these thin contrails were not evident in the GOES-14 visible or infrared imagery.

GOES-14 Water Vapor (6.5 µm) images [click to play MP4 animation]

GOES-14 Water Vapor (6.5 µm) images [click to play MP4 animation]

A comparison of the 3 Water Vapor bands (6.5 µm, 7.0 µm and 7.4 µm) available from the GOES-14 sounder instrument (below) demonstrated how each of the individual bands was detecting radiation emitted from a different layer of the troposphere; this was further shown by examining plots of the water vapor weighting functions for the 1 imager and the 3 sounder water vapor bands (calculated using 12 UTC rawinsonde data from Del Rio, Texas KDRT). The ABI instrument on GOES-R will have 3 water vapor bands similar to those on the current generation sounder instrument, but with significantly improved spatial and temporal resolution.

GOES-14 sounder Water Vapor bands 6.5 µm (top), 7.0 µm (middle) and 7.4 µm (bottom) images [click to play animation]

GOES-14 sounder Water Vapor bands 6.5 µm (top), 7.0 µm (middle) and 7.4 µm (bottom) images [click to play animation]