Gremlins are dismantling the nebula!

 Hi everyone! 

First blog post for the Satellite Convective Applications Experiment - Week 1, let's go!

The loop below shows an example of this from the Corpus Christi, Texas. Notice the convection moving out of the frame to the northeast is bounded by prob-lightning contours (Gif 1). My desire would be to have these better matched to the storms. Right now, the contours are too nebulous.

GIF one: MRMS reflectivity at -10 C overlaid with lightning cast 60-min probability. 

Why do I care about it's nebulousness? When I am providing decision support to an event, I want to know which cell is driving the highest probability, which is building and be able to anticipate the lightning threat based on the cells movement. 

As my partner in the testbed pointed out, the anvil(s) (see image one below) were merging and this was likely causing the nebulousness. 

   Image one: GOES East Day Cloud Phase RBG channel.

Our discussion began to expand to others in the testbed and an idea emerged to try and reduce the nebulousness. The idea was to use the GREMLIN Radar Emulation product to further train the lightning cast dataset so that the probabilities become anchored by the emulated MRMS product. 

Below is a GIF of the GREMLIN and MRMS product. With the GREMLIN product using some of the same satellite features as the lightning cast; the two products have some base level of compatibility. And so my challenge to the developers of these products is, an these two be combined such that lightning cast is mapped to the convective feature causing the probability. 

GIF Two: GREMLIN Emulated Radar on the left, and MRMS composite reflectivity on the right.

-Kilometers

UNR - Warning isssued for storm moving into SW SD. ProbSevere.

2310Z: After a lengthy internal struggle I decided to issue a SVR on a strong storm moving from NW NE into SW SD (2206Z issuance time). Primary reason for issuing was ProbHail which had values of 92% & as MESH of 1.62" right before the storm crossed into the CWA and a warning decision had to be made. This storm had rapidly intensified in the prior 20 minutes with a drastic increase in ProbSevere & MESH values & was moving into the area of our CWA I was most concerned about for severe weather this evening.

However I had reservations based on the near-storm environment the storm was moving into from SPC Mesoanalysis, which showed mixed-layer capping still in place. Furthermore the all-sky CAPE showed very low values less than 500 J/kg across SW SD & NW NE. Initially I dismissed this product as having values unrealistically low but I did notice an increasing rend in CAPE advecting into our CWA. Based off of a conventional near-storm environment analysis I was not a fan of the environment the storm was moving into but it's really hard to ignore a storm with ProbHail > 90% & MESH > 1.5 moving into your CWA, while under a severe thunderstorm watch, with satellite data showing an increasing trend in instability. Looking back at the storm after the fact, the MRMS reflectivity at -20C & 50 dBZ height were right on the line for issuing but at a threshold where I would have been willing to wait a bit & see what happened as the storms moved deeper into the questionable environment in our CWA. Without the tools we're testing this week I likely would have issued a SPS given the lack of reports from this storm & waited a few scans to see how it reacted to the environment across our CWA. In this case the storm began to weaken almost immediately after I issued the warning.

GLM data also was not that impressive on the storm even showing the weakening trend while reaching peak ProbSevere & MESH values I've witnessed with other storms in the west this week. I think this even reverse trend in GLM lightning activity added to my decision to issue a warning based on seeing it with other severe storms in ABQ/MAF so maybe I was anticipating a trend that doesn't actually exist.

Warning decision making relies on confidence in your understanding of the near-storm environment, & that the tools you are using are accurately depicting what is going on in the storm/environment. With this week being the first time we have seen GLM & all-sky products, & with limited use of ProbHail/Wind/Tor, I found it hard to decide which ones to trust when faced with conflicting warn/don't warn information between them and alongside more familiar conventional  products. Obviously this will change as we get more familiarization & training with the products which is one of the primary benefits of these HWTs!

GLM/ProbSevere loop of event:

All-sky CAPE/MRMS RALA loop of event:

Peter Sunday

MAF - SVR issued based on increase in lightning activity

2300Z: I decided to try & get a jump on the storm east of the already warned one in eastern Jeff Davis county. GLM was my primary tool used in deciding to issue a warning based on an increasing trend I began to notice around 2230Z. between 2230 & 2250 Flash density increased from 10 to 30 & total energy from 50 to over 100. The animation below I could have issued a warning even earlier when I first noticed this increase in lightning activity but waited until I saw more of an increasing trend in prob severe. ProbHail was at 6% when I first noticed the increased lightning trend & I waited until I saw an increase to 14% & MESH increasing from 0.5" to 0.74". At the same time I noticed a cooling trend on cloud tops on the GOES 16 clean window IR which added even more confidence to the lightning data that this storm would continue to intensify. Unfortunately I fumbled around with WarnGen a bit so my warning wasn't actually out until 2051Z but I made up my mind on issuance & began the warning process around 2040Z

GLM 4 Panel animation:

Around 2300Z the storm became more obviously severe with ProbHail of 84%, ProbWind of 68%, & MESH of 1.38".  I'm not anticipating receiving any reports out of this storm given the sparse population in that part of TX but given those numbers I would certainly consider this storm a severe candidate. Taking a look only at "conventional" storm interrogation products such as 50 dBZ height for 1" hail & isothermal reflectivity at -20C I don't think I would have made a decision on warning the storm until the 2255Z scan. Shortly after 2300Z the storm even took on supercell characteristics & began a turn to the right which certainly would have resulted in a warning. GLM products & ProbHail/ProbSevere without a doubt added value to my warning decision making in this case.

Of note is how the GLM fields actually decreased towards the end of the above loop despite the storm seemingly reaching it's peak intensity. I noticed similar trends yesterday watching storms in ABQ so this may be unique to GLM & storms out west.

UPDATE (2045Z): decided to reissue on this storm given  a steady trend in high GLM Flash Density Values, Prob Hail over 60%, & MESH near 1.5". Below is a 4 panel animation of the GLM fields/ProbSevere/& a MRMS 1km RALA over the whole period I was actively watching it.

Peter Sunday

MAF - RGBs Showing Convection Developing over the Davis Mountains

2115Z: Convection continues to develop over the Davis Mountains of SW TX with ice clouds now present as identified by the Day Cloud Phase, Day Cloud Convection, & Simple Water Vapor GOES-16 derived RGBs. Additionally, MRMS isothermal reflectivity shows our first echoes developing at the -20C level. However, no signs of any lightning activity yet on the GLM products.
This region has been my primary of interest for storms this afternoon so will continue to monitor these cells as the afternoon continues.

GOES-16 RGB 4-Panel:

Peter Sunday