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