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Leeside cold frontal gravity wave as viewed by GOES-18/16/19

By Scott Bachmeier •

10-minute GOES-18/GOES-West (left), 5-minute GOES-16 (center) and 5-minute GOES-19/GOES-East (right) Mid-level Water Vapor (6.9 µm) images, with/without hourly plots of surface wind barbs and gusts (knots), from 2100 UTC on 18 May to 1701 UTC on 19 May [click to play animated GIF]

The GOES-16 satellite was temporarily brought out of storage for annual testing (details) — which allowed for a 3-GOES (GOES-18/GOES-West positioned at 137.0 W longitude, GOES-16 at 104.7 W longitude and GOES-19/GOES-East at 75.2 W longitude) Water Vapor image comparison of the signature of a leeside cold frontal gravity wave (reference) that propagated southward across the High Plains during the 18 May – 19 May 2026 period (above). The images are displayed in the native projection of each satellite.

In the immediate wake of the cold frontal passage there were northerly/northeasterly wind gusts of 40-42 kts in the Panhandles of Oklahoma and Texas, as well as in northeastern New Mexico — and the highest peak wind gust at post-frontal METAR sites was 44 kts at Tucumcari, New Mexico (KTCC), which occurred at 0537 UTC (below).

GOES-19 Mid-level Water Vapor (6.9 µm) image at 0601 UTC on 19 May, with a cursor sample of the METAR report at Tucumcari, New Mexico [click to enlarge]

Surface observations showed that the cold front moved through Dodge City in southwest Kansas just before 2100 UTC on 18 May — and data from the Dodge City rawinsonde launch a few hours later at 0000 UTC on 19 May (below) depicted the shallow post-frontal cold air that extended from the surface to the 850 hPa pressure level, as well as dry air throughout much of the middle/upper troposphere.

Plot of rawinsonde data from Dodge City, Kansas at 0000 UTC on 19 May [click to enlarge]

A plot of the GOES-19 Band 9 weighting function — calculated using rawinsonde data from Dodge City at 0000 UTC on 19 May (below) showed that the peak of upwelling 6.9 µm radiation occurred at the 500 hPa pressure level, with no contribution from the surface. This helped to underscore the vertically-propagating nature of the leeside cold frontal gravity wave, which allowed its unambiguous mid-tropospheric signature to be evident in 6.9 µm Band 9 water vapor imagery.

Plot of the GOES-19 Band 9 (6.9 µm) weighting function, calculated using Dodge City, Kansas rawinsonde data at 0000 UTC on 19 May [click to enlarge]

Categories: GOES-16, GOES-18, GOES-19