The UW-CIMSS Cloud Top Cooling (CTC) product was utilized at the SPC mesoscale desk on 9/17/14 during a marginal severe weather event over South Carolina. The CTC product not only highlights where initial rapid convective development is occurring, but it also quantifies the vigor of said growth. See past blog posts (eg. http://atomic-temporary-39547612.wpcomstaging.com/2014/04/02/cloud-top-cooling-product-with-kansas-severe-weather/) for background information on the CTC product and its use in SPC operations.
The CTC product first signaled cooling of around -10 K/15 min in the IR at 1830 UTC in South Carolina near the Georgia border (Fig. 1), indicating convection was at least trying to develop. Over the next few scans, the product signaled multiple areas of significant growth with increasing intensity over much of the southern half of South Carolina. At 1915 UTC, cooling of over -40 K/15 min was measured with a storm that would be warned on 19 minutes later. Several of the storms would go on to produce severe wind and hail, with the first severe report coming in at 2035 UTC.
Figure 1: September 17, 2014 1815-2030 UTC GOES-East visible satellite imagery, Cloud Top Cooling product, NWS severe warnings, SPC storm reports.
The SPC forecaster on the mesoscale desk was monitoring the CTC product over the region, and referenced it in a related Mesoscale Discussion: “THE MODERATE INSTABILITY AND -10 C 500 MB TEMPERATURES ARE PROVING SUFFICIENT FOR RAPID CLOUD TOP COOLING WITH MOST OF THE STORM CELLS IN THIS REGION PER GOES-R CLOUD TOP COOLING PRODUCT” (Fig. 2). The forecaster mentioned that seeing many areas of significant cooling gave him confidence that the environment would be conducive to the development of severe weather. This is a good example of a forecaster using the CTC product output to enhance his understanding of the environment.
Figure 2: SPC MD #1724. MD text: http://www.spc.noaa.gov/products/md/2014/md1724.html
Bill Line, SPC/HWT Satellite Liaison
Satellite Liaison Blog 