MesoAnywhere was very useful during this event. While there was a meso sector across the Tennessee valley, MesoAnywhere did a great job providing useful details pertaining to warning operations. Growing cu was evident early in the event along with mesoscale boundaries. The product continued to provide value during the event as other channels were used to measure storm intensity trends.

GREMLIN struggled early in the event with a storm just north of the CWA over Whitley County, Kentucky. This storm quickly became severe warned as there was a large Three Body Scatter Spike (TBSS) and impressive tall intense reflectivity core with ZDR/CC/KDP drop out. GREMLIN caught on I believe after 5min or so, but reflectivity values were still lower and not as concerning as MRMS. It was also interesting to note the storm entering western portions of the forecast area looked more intense on GREMLIN at times. If there was no radar data, GREMLIN may have made me focus more on issuing a warning for the storm to the west of the CWA. However, OCTANE data clearly showed a stronger STD signal on the storm to the north which is what made me initially go look at the 88D radar data for it.

GREMLIN was a useful tool during the event as it did catch on to stronger cells that developed, but it was slightly slower than MRMS or 88D radar data at times and would smooth out more impressive signals in reflectivity that helped issue timely severe warnings for hail. If there is no radar data, GREMLIN is certainly still a useful tool. The more tools, the better!

Here is where OCTANE data clearly showed a stronger STD signal on the severe storm to the north compared to the one entering our CWA from the west. This gave me a heads up to go look at the 88D radar data to see if a warning was warranted. The smoother STD procedures make it slightly easier to see the signal.

OCTANE STD has been one of my favorite tools in the experiment. I found it very useful to quickly identify the strongest storms in my CWA that warranted my attention. It was also helpful for understanding storm intensity trends as it has cloud top cooling overlaid in the product. The low-med smoothing and high smoothing were easier to read than the sn smoothing STD procedure. The no smoothing was splotchy which made it more difficult for my eyes to quickly discern which storms required the most attention for potential convective warnings. The tool was amazing for all of the convective events through the week, but I could see this procedure not being as useful in certain convective modes where STD signals may be weaker. I would love to learn more about what thresholds to look for in the product! I’m sure that will be a great future research project, and I appreciate all of the hard work from the researchers involved with this experiment.

– Ricky Bobby

From 1940Z to 1950Z, there was a cell developing right over Madison county. If you look at the cloud top temperatures in the Octane 4 panel below, you will see that there is cooling spike. Gremlin also picked up on high reflectivities in the same area with actual ENI total lightning increasing in density. Gremlin also showed an increased lightning intensity signal. We issued a warning on that storm and ¾ inch hail was reported.

2149Z

Interesting feature with Gremlin that would possibly suggest that there is a hook on the storm noted below to the right. Hence we issued a SVR with TOR possible tag. Looking forward to seeing if there are any reports with this storm.

-Jolly Rogers

GREMLIN was doing relatively well early in the event capturing more intense cells firing up along the Sea Breeze boundary.

Some issues were then noted with new development along the boundary after initial cells began to collapse with convective cloud debris and leftover anvil overhang. GREMLIN hardly shows any reflectivity where MRMS shows new cells developing to the west of the more intense cell offshore.

GREMLIN struggled some with this cluster of storms further south as well, but it did do a great job of capturing the more organized cells.

The more intense cell shown in the GREMLIN figure above did intensify further with OCTANE products showing strong Storm Top divergence and shear. The speed sandwich showed nearly 40 knots of shear at this point and no smoothing STD had peak values near 5.5 10^-3 -s. The medium smoothing had values around 4-5 10^-3 -s. This was the strongest signature of the day and questions were raised on if a severe t-storm warning would be issued if there was no radar data. It is hard to answer this question given how new these Satellite products are to me. Knowing the environment was marginally supportive for downbursts or severe hail and this was the strongest signal of the day I may have issued a severe thunderstorm warning. It would have been a lower confidence warning, but it is better to be safe and issue the warning given there is no radar data theoretically.

A few scans later OCTANE products clearly showed the storm had already reached peak intensity and was beginning to weaken. Weakening storm top divergence/shear in speed sandwich along with weaker gradient in wind speeds were the signals noted. This would have given me the confidence to know another severe thunderstorm warning downstream was likely not needed. GREMLIN also showed reflectivities beginning to decrease around or shortly after this point providing greater confidence. Forgot to grab an image of GREMLIN for this.

– Ricky Bobby