Evolution of LightningCast Over Southern Montana/DSS Event In Billings

Upper level flow shows continued SSW flow aloft over the region, thanks to deep troughing remaining over the West Coast. Overall forcing through the afternoon is on the weaker side of things, but models show an upper level jet streak nosing into the area. Scattered thunderstorm activity has already developed (below) to the south of Billings in northern WY, and is expected to expand in coverage through the afternoon. The DSS event is noted by the large yellow “B” over Billings.

The 14Z PHS forecast output (below) showed 19Z MUCAPE values across the area ranging roughly from 1000-2500 j/kg (with highest values in the eastern areas). Looking further into the mid-afternoon hours, outside of MUCAPE values creeping closer to 3000 j/kg in far NE portions of the CWA, the PHS overall didn’t show any notable changes in values. PHS values of 0-6km shear also matched up fairly well with SPC Mesoanalysis at 19Z, and had values increasing to around 35-40 kts through the afternoon.

Below is the 19Z MUCAPE via the SPC Mesoanalysis page.

LightningCast right around 19Z showed the 10% probability contour still about 40 miles SSW of Billings at its closest point (below).

LightningCast right around 20Z showed the 10% probability contour still about 30-35 miles W-SW of Billings at its closest point (below).

Around 2045Z, the 10% prob. contour reached the DSS event(below), but overall activity continues to be slow to push NNE. The LightningCast Time Series is included to show the trend up to this point.

Fast forward to roughly an hour later (~2140Z), there’s been a bit of a jump in the LightningCast Probability/TimeSeries (below), with the DSS event now sitting with a roughly 35% probability of lightning in the next hour.

A few minutes later, another jump up in probability – up to around 50%. Below is an image that has the GLM FED (colored pixels) included with the radar, LightningCast, and ENI Total Lighting Plot.

You likely have already been talking with the DSS contact point, but this jump up in the last ~10 mins may warrant another update, conveying that there is an increasing probability of lightning occurring in the next 60 mins.

Not surprisingly, the LightningCast probabilities have continued to increase, also shown in the time series. Image is from 2220Z.

What’s the best way to pass along this information to the DSS contact point?

With this type of event, where it’s slow to move in (driven more by the upper forcing vs the somewhat random quicker-developing activity that can occur in high CAPE/low shear  and other types of environments) and no significant changes in the overall environment across the area, perhaps you could wait until it’s closer to 50% or more  before expressing greater concern for the threat of lightning.  In those instances where activity may be quicker to develop/strengthen, it’s not out of the question that values closer to the 25% contour would warrant greater concern. No matter the overall environment, I do believe the addition of a shorter-term probability (lightning within 30 mins)  would be beneficial.

– Bubbles


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New Four Panel

After a few days at the HWT I have decided to make a four panel of my own with the new products which has been working great! On the top left we have Octane Speed with Octane direction on the top left. We have Vis with lightningcast and GLM 1 min lightning on bottom left. On bottom right I have MRMS data and ProbSevere V3.  I was very happy with this display for situational awareness.

Also in the image below we can easily spot a stronger storm in a cluster of cells in Park County looking at directional and speed shear with Octane. Then we can quickly look down at ProbSevere and see its on the one storm being highlighted. That tells me this is the storm that I need to watch over the next 10-15 minutes for development.


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Satellite HWT Day 3 Carl

Wednesday Satellite HWT Thoughts

PHS Model Comparisons and Thoughts

Above: Top is HRRR SHIP parameter, bottom is PHS SHIP parameter.

Looking at some of the convective parameters and indices around the CWA I was working with today (PUB), one thing that really stood out to me was how “splotchy” many of the parameters were when compared with the HRRR model. It’s very hard to believe that the model, especially at a 3 km resolution, is able to obtain that level of accuracy with regards to these parameters, or at the very least having gradients this sharp in many of these parameters doesn’t make much sense. Wondering if some of it is being driven by the extreme CAPE gradients that do show up later on, which are certainly going to be drivers in many of the severe indices.

Another thing I noticed is what looks to be a wave-like numerical instability within the first hour of the model – this could be having some big impacts on the model forecast, as you can see these reflected in the base fields (T, u, v, etc) and then having impacts on many of the other derived parameters that last through the forecast period, as shown in the image below:

CAPE also seems to initialize really high, then “jump” down to a lower value at the first hour. This is quite a large “adjustment” from the initial conditions that the model seems to start with. Shown below are hour 0 of the 14Z run and hour 1 of the 14Z run from Wednesday 5/24.

You can also see the numerical instability within this field that is in place across a large portion of the domain.


Octane was able to capture an interesting view of the Above Anvil Cirrus Plume on a very powerful storm along the New Mexico/Colorado border during the afternoon hours. The cirrus is a bit slower than the surrounding clouds within the sheared environment, providing that “V” type shape that we’ve come to associate with some of the strongest updrafts:

Another good example of using Octane for surveillance of storms – the direction product really highlighted another storm that quickly grew on the flank of another severe warned storm. Big value especially in areas where radar coverage might be limited by mountains, such as in the CWA I was working in today (PUB):


Used the LightningCast product extensively for DSS purposes today. We had a pretend outdoor event located in Pueblo, Colorado. A very strong thunderstorm (MESH estimated nearly 3″ or larger hail at one point) which passed within a few miles to the south and east of the city. I used the LightningCast probabilities in AWIPS overlaid with satellite data to provide multiple updates to Emergency Management, using it to confidently state that probabilities of lightning were increasing as storms approached from the south. Lead time for action would have been within the 45 min to 1 hour range. Was able to confidently say they would see lightning within the 10 mile range a good 15-30 minutes before the first strike occurred within the range per the ENTLN network data. Below is the LightningCast time series as output on the webpage for the KPUB airport, which is very close to where the DSS event was taking place:

There is definitely some very actionable lead time here. As a forecaster, having this type of data available to me outside of AWIPS is a game changer. I know it may be challenging, but being able to click on a point like this and get this type of information would be huge for briefings and emails with decision makers. Right now we are limited to airports. Even a relatively coarse mesh that would allow me to pick a close point would be extremely useful if these images can’t be generated on the fly. Other possible ideas include only generating points within a certain LightningCast threshold (say 10%), or generating them on the fly based on a click query. That all said, even in its current form I will be using it going forward, and making a point to share it with my office and WCM for DSS.

I also made a social media type graphic using the LightningCast product for hikers, given the large number of mountains within the CWA. Perhaps would have been a bit more meaningful to have sent this as storms were beginning to form, but they were already cooking once we got spun up and started. Highest probabilities were hugging the mountains where storms were forming. If I were formally posting to social media, I may have added some lightning safety graphics or something to that effect as part of the post (twitter thread, multiple images in Facebook post).


This product does a great job in my opinion combining information from the FED and MFA. I found it useful for detecting lightning jumps within storms while still maintaining information about the overall coverage of lighting. Would happily use this as my primary GLM viewing option in AWIPS.

-Carl Coriolis


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LightningCast Over Eastern MT

This image shows Day Cloud Phase Distinction, LightningCast, and 5 Minute CG Flash Lightning Plots for NLDN and ENTLN across Eastern MT.  While LightningCast provides a lot of information, it’s easy for it to overwhelm forecasters in situations like what’s shown, especially if other colorful imagery is included.  A suggestion is to give forecasters the option to load LightningCast in 10% increments from 10-90% (10, 20, 30, etc).  Then, forecasters can turn the individual increments on or off depending on the situation (i.e. lots of severe weather can prompt the lower values to be turned off, or partners concerned with the initial start of lightning can prompt lower values to be turned on).  Having the ability to change the color, line style, and line width for each increment would also be nice.


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LightningCast Graph For Lubbock Airport

This is a great example of LightningCast application that could be used for TAF forecasts or DSS. As the image above shows you can see the chance of lightning slowly going up for the airport getting to around 20 to 30% before the first lightning strike within 10 miles and above 60% before the first strike before it hit within 5 miles. More localized research would have to be done to see the threshold for DSS and TAFS. But in this example if we used 30% threshold we would have a 15 to 20 minutes lead time before lightning got within 10 miles of the airport.


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LightningCast Gives Advance Notice for DSS Event

Lightning Cast (parallax corrected) had a 75% contour for lightning within the next hour (screenshot taken at 21:51Z) for our railroad DSS event. Notified the DSS event about the high lightning potential within the next hour. Went back to look at radar and lightning data for 22:50 to 22:54Z and there were CG and CC strikes just north of the Railroad DSS event in Levelland, TX. This allowed us to give them an hour to make any ground preparations regarding personnel.

-Dwight Schrute

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LightningCast Gives Advance Notice

Thunderstorms were expected to develop in northern TX on May 23rd. Using Day Cloud Phase Distinction, a specific cell seemed to be quickly forming. Minutes after this trend was noticed on satellite, Lightningcast started tracking it. A 10% area was forecasted at 1927Z, followed by 25% at 1930Z, 50% at 1933Z, and finally 75% at 1942Z. While the 75% forecast dropped off for a brief time, it still was predicting lightning over the next hour. What happened? NLDN and ENTLN detected a CG strike at 1959Z (extreme northeast Roosevelt County). The storm went on to continue producing lightning.

– Champion

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Challenge With A DSS Event With Scattered Thunderstorm Development…focus on LightningCast.

Sea Breeze and outflow boundaries in place over the Florida Peninsula made for a tricky forecast during the afternoon hours, as thunderstorms could and would quickly develop just about anywhere along that boundary. Lightning up to this point by far was the main threat from these storms…as most storms were not strong long enough to cause notable hail to be a concern, but with storms having the potential to “die off” quickly as well, wind was more of a concern.

With the initial onset of early afternoon activity, providing DSS support and giving the local contact more detailed information was on the ‘easier’ side. LightningCast around 19Z was showing increasing probability contours of lightning within 60 mins at the DSS site (image below was at 1901Z. The DSS event is noted by the yellow “C”.

By around 2035Z, activity had increased in coverage and drifted northeast, closer to the DSS event, shown below by the increased coverage of ENTLN lightning plots and the 75% probability contour in the area.

The challenge since then is that more scattered/widespread activity has developed (and died off), in what seems at times to be in fairly random areas…but are for the most part tied to the moving outflow boundaries from previous storms (seen in radar image below at 2203Z).

Not surprisingly, as a result of all of this activity, LightningCast over this entire area has been remaining mostly around-above 50%, with many spots at/above 75%.

The challenge is what is the best way to convey this information to the DSS point of contact? Below is an image showing the LightningCast probability contours at 2212Z, along with the LightningCast Time Series for the DSS site (noted with the yellow “C”).

There is an overall lull roughly between 2110Z-2150Z (probability is closer to/lower to 50%)…but it never drops below 20%.  

Personally, looking at this time series and given the environment/set up and evolution of storms so far, I would have a difficult time calling the DSS point of contact and saying the threat of lightning is low…as another storm could develop as soon as I hang up. You don’t want to totally shut an event down, or be constantly calling the point of contact with updates (unless you know the contact likes that much communication). I don’t claim to have the answers, just thinking out loud, but it’s something to think about if using this product to communicate with DDS contacts.


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Taking a look at LightningCast in West-Central Florida.

Thunderstorms have been gradually increasing this afternoon along the west coast of Florida, and wanted to take a look at the evolution of the LightningCast product vs when flashes were first reported. Want to note upfront, there was an issue with GLM data, so used the 5-min (1-min update) CG/Cloud/Pulse ENTLN1 lightning plots to see when activity developed.

Below are images showing when the 25, 50, and 75% probability contours of lightning occurring in the next 60 minutes appeared, focused on Sarasota and Lee counties. For both counties, the 25% probability contour first appeared at 1838Z, 50% contour at 1851Z and the 75% contour at 1854Z. The first lightning strikes appeared in Lee County at 1858Z (a 20-min lead time from the 25% contour). The first strikes appeared in Sarasota County at 1906Z (a 28-min lead time from the 25% contour).

The image below shows the 25% probability contours showing up in the Sarasota and Lee Counties at 1838Z.

The image below shows the 50% probability contours showing up in the Sarasota and Lee Counties at 1851Z.

The image below shows the 75% probability contours showing up in the Sarasota and Lee Counties at 1854Z.

The image below shows the first lightning strikes showing up in Lee County at 1858Z.

The image below shows the first lightning strikes then showing up in Sarasota County at 1906Z.

– Bubbles

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GLM and Lightning Cast

The GLM parallax showed up again Thursday, June 16th, over the PBZ area. This was even more evident than yesterday’s event in WI that was written about in a blog post.  Figure 1 has ProbSevere, LightningCast, GLM Flash Extent Density, and ENTLN data overlaid in a 4-panel.  This case was fairly simple to “self correct” the parallax as the GLM was clearly displaced to the north of ProbSevere (as well as the base reflectivity).  Really once you get a few cases under your belt recognizing the parallax, it’s not too challenging to keep that “self correct” in the back of your mind.  One interesting thing to note about Figure 1 is the storm just outside the PBZ CWA just south of Mount Veron, Ohio (See bottom left in Figure 1).  The ProbSevere and GLM FED are lined up perfectly and this is a great example of utilizing the lower threshold in the colormap. The bullseye shows up much nicer than the larger thresholds in the top two images.

Figure 1: GLM with ProbSevere and LightningCast

– Podium