Category: LightningCast

Adding Latitude/Longitude on Dashboard May Help Locate Mistaken Entry

Posted in DSS, LightningCast, SPG2024 on by Kevin Thiel.
While doing DSS for the PGA tournament, there was an instance where we were uncertain whether the dashboard was matching the values on the map. Below, the probability of 1 flash and 10 flashes are shown. Using the sampling tool within the 10 mile range ring, the values never exceeded 50 percent. However, on the dashboard for the PGA Attempt 3, there were values above 70 for a single flash.

Trying to find the reason why, the most likely situation is that the forecaster may have mistyped, either mixing up decimal points in the lat/lon, or swapping two digits around. It may be helpful to be able to go back and edit the entry if that occurs or be able to view the lat/lon point to be certain whether a typo occurred putting in the entry.

In this case it wasn’t a typo – It was parallax!

Kadic

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Using GREMLIN for Time of Arrival

Posted in DSS, GREMLIN, LightningCast, SPG2024 on by Kevin Thiel.

LightningCast has been running high near the PGA Tournament today near Fort Worth as a result of several thunderstorms around the region, but not over the region. As a result, decided to swap over towards trying to use GREMLIN to find the time of arrival of the boundary noted earlier.

So an attempt was made to highlight this in the DSS image to provide an estimate of when these hazards would arrive. Perhaps another proofread would’ve caught the initial typo from copying it over. However, a value of about 40 percent was noted. Partners still had information that storms would become increasingly likely over a narrower time frame in addition to the probabilistic information from LightningCast.

But nature had other plans with a strike and a few pulses of lightning over the event at the time this was “sent out”. An area of weak convection was in the area, and so I would’ve thought that this would not produce lightning.
Sneaking in information on the RGB evaluation, you can see how this was not a young storm and likely something in decay, and that may track with a bit of the surprise element.

Kadic

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Tracking Convective Development With OCTANE storm top divergence and LightningCast

Posted in LightningCast, OCTANE Speed Sandwich, SPG2024 on by Kevin Thiel.

Developing convection along a surface front in eastern Kansas was producing signals in the OCTANE storm top divergence product, signs of glaciation, in the day cloud phase product, and increasing LightningCast probabilities. Along northern areas of the surface boundary, the divergence product and visible characteristics were stronger, while updrafts further south still struggled to sustain themselves. This may be due to residual convective inhibition evident on MCI ACARS soundings. Even about 20 minutes after these screen shots were taken, the GLM activity was fairly weak, while the storm top divergence only really showed showed up on storms near and north of the KC metro. While severe convection is still likely downstream, the OCTANE divergence product definitely highlights where better synoptic forcing is overcoming any convective inhibition.

 

 

-Joaq

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Warning vs DSS – “WFO DMX”

Posted in DSS, GLM, GREMLIN, LightningCast, OCTANE Speed Sandwich, SPG2024 on by Kevin Thiel.

It was interesting when comparing the Warning side of the house today versus the DSS side. When we (Cumulus and Kadic) were discussing this and picked two of the tools we used the most, there were similarities and differences:

For Warning Ops: OCTANE and LightningCast

OCTANE proved very useful in interrogating convection. LightningCast was also a helpful diagnostic tool in highlighting the potential for and track of intense convection when used with ProbSevere.

OCTANE:

Here’s a look at 2 particular instances from OCTANE:

A combination of cloud top cooling in OCTANE and subsequent divergence aloft was a helpful clue in assessing the potential of a storm that was distant from the radar. It was caught a little later in analysis, but OCTANE proved helpful in diagnosing the storm and deciding to pull the trigger.

 

 

This next instance was a warning that was issued solely using OCTANE and seeing how well it lined up with radar. The warning targeted the center of where the maximum storm top divergence was taking place, and then stretched down towards the south to account for parallax. The warning decision was made for the impressive cloud top cooling and pronounced divergence that appeared in the scans leading up to the warning. The panel on the top left shows the OCTANE speed, and it transitioned to a blue color leading up to the event.

 

 

LightningCast and Radar:

As the line shifted east into the area, ProbSevere stood out, while the LightningCast steadily increased. The left hand panel depicts GREMLIN, and it properly highlights the southernmost storm as being the most intense. Unfortunately, not every storm that we issued warnings for got a specific screenshot, but when looking at LightningCast, areas that were likely to experience 10 or more flashes with a 70% probability seemed to correspond well with ProbSevere values would support issuing warnings.

Below is the example of what MRMS looked like the moment DMXSVR005 was issued solely based on OCTANE. Much of the SVR encompassed the highest LightningCast values with a probability of 10 flashes of 70% in yellow and the various ProbSevere contours. Again, this highlights how useful these tools can be in performing storm interrogation. However, when thunderstorms are numerous, this may be a lot to run through. They are definitely useful tools in the tool belt, though.

For DSS: LightingCast (especially the Dashboard) and GREMLIN/GLM.

– LightingCast: I REALLY like the form and Dashboard. It helps focus on the DSS site specifically and organizes the data really well to where I would feel comfortable explaining/showing an EM the graph of   lightning probabilities. Honestly, I could bring this back to my home WFO right now and use this for DSS events this summer. A couple things that could be added to make it even more awesome: adding more options for ranges (right now there is only 10 miles, perhaps adding 15 and/or 20 miles). Folks could then choose which to display in the graph. The other thing (fairly minor), perhaps reversing the size of the bubbles for the GLM data (smaller range, smaller bubble). But, this is personal preference – maybe if this could be customized by the user like the colors?

– GREMLIN/GLM: GREMLIN followed the storms a lot better today (seems to do better with more intense storms versus run of the mill/sub-severe ones). I used a two panel display with GREMLIN on the left and MRMS on the right with GLM and LightningCast and compared the two. I used time of arrival for the storms to 10 miles outside the DSS event and also at the site itself. GREMLIN was able to keep up with MRMS really well! I am becoming more and more convinced that this could be a really great product to help if a radar goes down or there is a radar hole (in data).

Overall, it seems as though OCTANE was used more for warning ops versus DSS, but LightningCast was used by both the warning operator and DSS forecaster.

Forecasters Cumulus and Kadic

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Using GREMLIN and LightningCast for Warning Ops and DSS

Posted in DSS, GREMLIN, LightningCast, SPG2024 on by Kevin Thiel.

GREMLIN continues to perform well with regards to the overall picture of precipitation and convection. In fact, in the example below, GREMLIN seems to be catching on to the northern extent of the line breaking apart and the southern portion becoming more intense. However, it seems to be a bit slower than the MRMS data.

LightningCast could be more useful in this case if the thresholds were modified (25 flashes versus 10) to better identify and focus on the more intense convection.

LightningCast overlayed on GREMLIN emulated radar (left) and MRMS Composite Reflectivity (right)

Looking at the LightningCast dashboard for our DSS event, probabilities of lightning are increasing. I found that this is actually an easier way of being able to communicate lightning probabilities for a site (or a range around the site) versus using the map (seen above). This would allow me to let an EM or site official know that probability of lightning is near 80% for 10 miles form the site (within the next hour) and 50% at the site itself.

 

LightningCast Dashboard for Belin Quartet Summer Concert Series (Des Moines, IA)

We provided valuable support. A message was sent nearly 45 minutes ahead of time following the issuance of a Severe Thunderstorm Warning to the west.

If our partners are simply looking to delay, LightningCast may also prove helpful in giving the all clear if you don’t see anything upstream on radar. The values react well as convection clears the site. This is also great in helping you know for sure when the last lightning flash took place, and it can help us give better information.

 

Forecasters Cumulus and Kadic

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Lightning Cast at Initiation near St Joseph MO

Posted in LightningCast, SPG2024 on by Kevin Thiel.

Wanted to provide an assessment of LightningCast on the cells developing on the KS/MO border. This is the same area of initiating convection previously mentioned in the “Tracking Convective Development…” blog post. This post will focus on the storms moving between Kansas City and St Joseph.

Lower probabilities for Lightning Cast (10% to 25%) began appearing for these particular storms as early as 1856Z. Probabilities for 10-flash began appearing after 1922Z.

The first cloud flash detected by ENTLN occurred at 1924Z. The first flash detection by GLM was at 1928Z. The first CG strike (NLDN) occurred at 1946Z.

All in all, Lightning Cast provided a considerable amount of lead time, which I found to be useful.

 

The Lightning Cast time series for KSJT (airport near St Joseph) also showed a steady increase as these storms approached and strengthened, with lead times. Probabilities increased above 50% about 10 minutes before flashes began being detected near KSJT.

–Insolation

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End of Day 1 Thoughts

Posted in GLM DQP, GREMLIN, LightningCast, OCTANE Speed Sandwich, PHSnMWnABI, SPG2024 on by Kevin Thiel.

Thoughts at the end of Day 1…

The LightningCast product I think would be VERY useful for DSS. Overall, when seeing it perform in real-time, the increasing LC probabilities seem to eventually correlate well with GLM flash density. I look forward to using the DSS form this week and seeing how that works for specific sites.

The GREMLIN product seems to be a great way to see the overall picture of precipitation (say, for a region). I think it struggles with precipitation intensity a bit (>45 dbZ) both for storm cells and for heavy stratiform precipitation. At the “storm” level, I have seen instances of the model not following the evolution well (either too intense or not enough).

For OCTANE, it was easier to pick out an example of CI and divergence with the IR versus the Visible products. I could use the direction product on its own in operations, but I really like having the speed, direction, and cloud top divergence all together in a 3 panel to identify convection.

PHS did a great job today identifying convective initiation when overlayed on visible satellite imagery. I look forward to seeing how this performs in other areas of the country this week.

Still learning how best to utilize the GLM DQP; but, when looking over Cuba, I was able to better understand how it locates areas where the data might not be the best. I hope to learn more about this product through the week and see more examples of its application.

Forecaster Cumulus

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Identifying potentially stronger thunderstorms with IR OCTANE divergence and LightningCast

Posted in LightningCast, OCTANE Speed Sandwich, SPG2024 on by Kevin Thiel.

 

Displayed here are OCTANE products built from both visible (right panel) and IR (left panel). What caught my eye is the characteristic of the OCTANE direction in the IR panel, where directional divergence is showing up much more clearly than in the visible OCTANE product. This is especially showing up in the northern set of storms, where LightningCast is also highlighting for a probability of >10 flashes in the next 60 minutes (shown below). These both highlight an area with a higher probability for more intense convection in the near-term.

-Joaq
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LightningCast and DSS

Posted in DSS, LightningCast, SPG2024 on by Kevin Thiel.

Viewing CI and LightningCast (LC). LC probabilities on the SW portion of the storm (in the center) at 1958Z ranged between 70-75%. Just before GLM signatures pop up at 2007Z, LC probabilities jump up to around 82%. Not included in the animation, but at 1951Z, LC probabilities were around 50%. The overall trend upward would give me confidence that I can use this product to tell an emergency manager the potential for lightning is medium to high within the next 10-20 minutes (using this case, hypothetically starting at 1951Z).

Lightning Cast product overlaid on Cloud Phase Distinction on the left and radar reflectivity on the right. 20 May 2024

Forecaster Cumulus

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Waiting For Convection To Go

Posted in GREMLIN, LightningCast, OCTANE Speed Sandwich, PHSnMWnABI, SPG2024 on by Kevin Thiel.

While looking for thunderstorm initiation, my eyes are turned towards anything that informs me whether convection will develop further or decay. There have been several things to note while waiting for instability to move into the region.

The main forecast challenge is the favorable ingredients to produce severe convection has to be advected into the region. The WRF with PHS data demonstrates that initial convection intensifies later in the day as better instability arrives across the region on the bottom right panel. This also corresponds with better dynamics noted across the others entering eastern Colorado. Model reflectivity on the bottom right increases as a result of better forcing over time. Until then, it’s monitoring at what point things actually start turning the corner and using the new tools available to find that point.

 

And so far, the things found have been what it’s not. So here are some things being observed in this period of waiting. At the beginning of the day, one of the things I noticed was related to the OCTANE detecting warming and cooling. As clouds moved off snowy foothills, it was apparent on the viewer where water clouds appeared warmer than the snow surface, and caused a pocket of cooling to appear on the eastern foothills once satellite could see the frozen snow, and warming whenever a cloud layer shifted overhead obscuring the snow. In the middle of convection, this would probably be irrelevant, but just a thing to note while we wait.

 

 

I like the idea of mashing together several products that we’re testing at once. So, I’ve applied the LightningCast, WRF with PHS CAPE, and GLM. The idea will be to monitor how the storm is pulsing compared to with what information is provided from PHS. It’ll also help track in what area LightningCast is lighting up and whether it is heading towards a favorable or unfavorable environment. With LightningCast aiming for detection within an hour, it began highlight a cell that corresponded with favorable instability. The combination of these two helped me hone in on this cell as being more likely to produce lightning than a similar LightningCast to the northwest. The 10% contour formed just before 20z, and steadily increased leading up to the first flashes on GLM roughly 30-40 minutes later. Nicely done!
While waiting, a small cell caught my eye. The area was almost completely clear, and showed very dark on visible imagery, to being cloud covered near Palmer. This made it appear this was about to blow up, but then you can see the OCTANE tool quickly reverse course once it becomes clear it will not develop and it begins to come down on visible.
Off to our west, there were a couple cells. Analyzing the tool on GREMLIN, the southern cell was less intense on GREMLIN compared to MRMS, and reversed for the storm to the north. However, neither are particularly intense, but it does indicate to keep a watchful eye and use other products like GLM to assess intensity.
As we move past 22Z and how the WRF with PHS data, it has done an excellent job forming the convection near the Denver Airport, but by Shamrock/Leader/Adena, that cell has not formed. This is creating a region of spurious data due to convective feedback. Some of the model appears to drive convection by the cold pool from this storm meeting instability advecting in from the east. It then focuses on this cell over the others, but this appears unlikely to verify at this point given how it is performing so far. By 00z, the 0-3km SRH bullseye creeps above 1600 m2/s2 moving towards Fremont. I won’t put the image of the new cycle that just came in, but the bullseye got more dramatic over 2000 m2/s2. Not sure if how much those magnitudes are in the realm of possibility.
One of the interesting behaviors lately has been a few storms forming in the cold pool as we approach 23Z. There has been convection developing on the western side of decaying cells. This has me thinking about how this would look for backbuilding precipitation. Would it have this look of the cool purples remain anchored in place while reds for new convection continuously appear to upstream that rides atop the areas of divergence? The signals may not appear robust, since there may not be fast storm motions.
Looking back at LightningCast, I have noted the known limitation of the forecast trying to bridge separate pieces of convection. The gap seems quite large though, and I wonder if there may be other means to QC the LightningCast with existing radar without making it slow to process. Or we can trust that the human eye is capable of noting that radar will confirm the lack of reflectivity at -10 C or higher.

That’s all I have today!

Kadic
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