Observations from BUF on Thursday June 16th

Optical Flow Wind Storm Top Divergence Can Aid in Warning Operations

The storm of the day produced a 2.5” hail stone near Cato, NY.
Strong storm top divergence signals an intense or intensifying thunderstorm. Matched with upper level radar scans, satellite interrogation (clean IR), and ProbSevere, optical flow wind products may be another tool to aid the warning forecaster and/or storm scale mesoanalysis,  Below are the corresponding optical flow wind storm top divergence images approaching 4 PM EDT (3 PM CDT) when the sig severe hail was reported. The thunderstorm of interest is centered just south of eastern Lake Ontario.

LightningCast as Graphical Messaging/IDSS Tool

As the DSS and graphics person for BUF, I took the opportunity to highlight the utility of LightningCast for Graphical NowCasts and DSS graphics. The fairly broad brushed nature of the lightning probability contours at the timesteps utilized for graphics I think is a positive for a few reasons: they show actionable probabilities (10+, 25+, 50+, 75+) that users can understand; the contours are akin to annotations on a radar graphic, so would be a time saver; and finally, broad brushed is a way to prompt users and partners to seek out more information, like real time zoomed in radar data, perhaps calling or sending us a chat on NWSChat, or even simply keeping an eye on the sky and listening for thunder. The parallax corrected product in the images below I feel would be more useful for graphics of the nature shown below. Ultimately, for operational use, there would probably need to be some work done to ensure they are not confusing to the user and aesthetically pleasing.
Graphical NowCasts for our websites and social media
Graphic for IDSS Event

A Case for the Sharpened GLM FED Color Scale Used this Week

Over the course of satellite product interrogation this week, the GLM FED stood out as one of the most useful products.  Below are examples from in/near the BUF CWA at 2043z and 2047z. Note that the top of the color scale was set to 128 flashes/5 min over the grid point vs. the default 256 flashes/5 min in AWIPS. The FED also paired well with the MFA and TOE on this 4-pane procedure.
The color curve used this week really popped and correlated well with frequent ENTLN detections. Another example below from shortly after 6 PM EDT (2202 and 2207z)  shows that there will be instances where perhaps an even small color bar range would be useful.
While the strongest storm at this time still showed up well on the AWIPS default color bar range, the 128 flashes/5 min top end of the range (top right) helped it pop even more and corresponded well conceptually with the ENTLN cloud flash detections. Furthermore, the thunderstorms to the north of the strongest thunderstorm showed up better from an SA perspective, if you have been focusing on the strongest storm for warning ops. The smallest color bar range on the bottom left further enhances the above described effect.

Addendum: GLM Flashes and a more smoothed FED

The excellent COD NexLab Satellite and Radar page added within the past year the GLM flash centroids to their GOES derived overlays. From an apples to apples perspective with respect to the ground based lightning detection network displays, this may be a useful product to add into AWIPS.

Addendum 2: Would a more smoothed FED be preferable?

Below are a few web based examples of FED displays.
A case can be made that these smoothed FED examples would be somewhat less obtrusive than the default AWIPS FED display, especially for storm scale interrogation by the warning operator or storm scale mesoanalyst.
– Hurricane84

Supercells and Optical Flow Winds

With the storms moving out of La Crosse’s CWA, I’ve got a bit of time to finally take a look at the Optical Flow Winds.  I’m intrigued by the product to say the least.

Here is a still image of the GOES-East Meso1 sector today with the string of supercells ongoing (and tail-end charlie in NE Iowa).  One thing I was curious about was how well this could detect storm top divergence.  The radar data was pretty noisy in AWIPS so it was hard to see this in those products.

Here is what the “base” product shows.

Now let’s overlay the upper-level winds as detected by this product (roughly the 100-50 hPa layer although I wouldn’t be surprised if some storm tops are going above this:

A user can also overlay lower layer wind fields to see what could be happening in those areas.  The key thing was though to see what the storm-top divergence may look like:

And that’s pretty impressive for an optically derived wind field!  Individual turrets may be showing up where there are enhanced area of convergence/divergence couplets not the ones on the edge of the cloud detection).  It isn’t perfect though:

There is a lot of variability from scan to scan on the strength of the divergence field but there is enough of a signal to figure out where the strongest couplets could be and which storm tops they could be associated with.  We couldn’t overlay radar data or the 3.9 micron “Red/visible” channel with a divergence product to make a 1:1 comparison; something to consider would be a grid that could be overlaid on a different ABI image to do a visual comparison to this product.

I’m impressed!

– Hank Pym

Pre-Convective Environment Across GRB

With a busy day still underway across Wisconsin, the use of the Optical Flow Winds, GLM, Prob Severe, and NUCAPS soundings were a big help in looking at the pre-convective storm environment and in warning operations.

When it came to looking at sounding data we had a NOAA-20, and AQUA pass for the polar orbiting satellites, that we could then compare to the special observed sounding from GRB.

There are some spatial differences in the locations since each satellite doesn’t pass over the exact location and the observed sounding came from the GRB office. I ended up grabbing NUCAPS soundings from west of the office where I thought the better storm environment would be. Regardless of this they do show great information over a temporal and spatial scale.
Just between Aqua (bottom image) and NOAA-20 (middle image) you can see that the environment becomes much more moist over time (AQUA came around 19Z and NOAA-20 came around 18Z). The increase in temperatures and dew points in the low levels between the two NUCAPS soundings show that there was increasing low level lapse rates and increasing CAPE through time. Then compare both of these to the special sounding sent out by GRB, you can see AQUAs vast improvement in the low level over NOAA-20. The one caveat seems to be the smoothing of the values in the mid levels. Smoothing seems to have decreased the values almost too much for both satellite soundings. It is fairly within reason given that there is a dry layer in the mid levels on the observed, but the smoothing looks to have slightly overdone it.
Moving on to the GLM, it was very helpful when boosting confidence in the warning operations. There were lightning spikes collocated with increasing rotation and reflectivity. The one things worth mentioning is to have a reminder or maybe even have offices lower/change the color curves for FED prior to the start of an event. It could even be a permanent change that some offices make.
Since I was the only one in the group to check, compare, and lower the FED color curve accordingly it was much easier to pick out lightning jumps. From the graphic above alone, 0-65 was much more informative than 0-128 or 0-260.
The last thing worth mentioning for the day was the Optical Flow Winds. While this was helpful in a warning environment to look at storm top divergence and speed of the winds at the tops of clouds, I was able to find another great use for it. In the pre convective environment I had pulled up the Optical Flow Winds and noticed that it was tracking winds and speeds of clouds over Lake Michigan. In an area where any wind information and observation data can be very sparse to near non-existent. The optical flow winds could be very helpful for open waters forecasting.
-Cirrus Fields

A Comparison of the Optical Flow Winds “Divergence” Product and KMVX Radar Storm-Top Divergence

By 2200z, a strong cluster of storms was ongoing in northwestern Minnesota ENE of the KMVX RDA while moving northeast. Below are a set of 4 figures showing the divergence at the cloud top of the ongoing cell, with a cyan circle outlining the updraft area.

Here is a comparison of the Optical Flow Winds divergence versus storm top divergence provided by traditional means:


>100 – ~115 kt

~80 – ~105 kt

>100 – ~150 kt

> 100 – ~130kt

While the divergence output wasn’t as high, it seemed to behave consistently below the traditional storm top divergence which means it could be adjusted up in the forecaster’s head. I’d love to see a little more discerning from the color curve for divergence, as it shows little difference, and when it goes over 100, it is all red. Also, it would be nice to see the exact unit that it uses, as it seems assumed that it’s kts.





PHS, NUCAPS, Optical Flow, Prob Severe Fun


Today worked out well with PHS and NUCAPS. NUCAPS data came in shortly after opening up our work stations. We decided to compare the output between PHS, NUCAPS, and SPC mesoscale analysis. The variable that we chose was surface CAPE.
They all seemed to match up well highlighting the higher instability to the south that would gradually  push north this afternoon. It was definitely a confidence builder in each product to see the agreement between them.

Optical Flow

We also decided to compare the Optical Flow winds to SPC mesoscale analysis. Once storms developed a bit more, you can pick out a slight directional divergence signal in the flow. Looking at SPC mesoscale analysis there is also directional divergence is present in the mesoscale analysis.
Overall looking at these two examples, using these tools together can be a way to verify information and give the meteorologist more confidence (or less) in a specific product to help them with forecasts, DSS, and warning operations.

Prob Severe

We were able to compare Prob Severe V3 to the time when there was an observed report and when the new tornado warning came with a radar observed tag due to a CC drop. The first image is when there was a twitter report of a tornado around 2142Z in SE Darke county.

At 2144Z the Prob Severe V2 tornado jumped to 21% while V3 only went to 6%.

The next image below is when the radar confirmed tornado was reported.
– Noctilucent & Matador

PHS CAPE localized maximum compared with storms developing in the area

PHS CAPE values increase from north to south over Fort Stockton. This correlated well with RAP mesoanalyzed SB CAPE on SPC webpage. Storms actively going up along this gradient as an outflow boundary pushed south during the early afternoon from overnight convection over Oklahoma.

PHS CAPE 18Z 1 hour forecast for 19Z

PHS CAPE 18Z 2 hour forecast for 20Z.

Storms developing over Fort Stockton via Day Cloud Phase Distinction on GOES 17 Mesosector

We showed above that the north side of the outflow would contain more instability – which is directly related to the moisture from the morning MCS outflow. The Gridded NUCAPS provides additional insight using the 850mb moisture fields from both AQUA and NOAA20 respectively – validating our hypothesis.

We double checked since there was a dust advisory/dust in the forecast and yes – Dust

Don’t warn if pop = 0

Convection was skirting the northeast portion of the CWA so we’ll use the recent pass of NOAA-20 to view the potential for convection redevelopment to the west and affecting the forecast in our CWA. Here are the Modified NUCAPS soundings:

The top image is for the sounding in Jones county, below is Scurry – which shows a capping inversion still in place.

Storm Motion

Weak winds aloft and throughout the atmosphere have contributed to very little in the way of storm motion. Hence, locally heavy rainfall may begin to evolve, even over an area that has received very little rainfall in the last 6 months.

Optical Flow Winds in the 200-100 mb level.

Day Cloud Phase valid 2041Z.

Day Cloud Phase valid 2141Z.

PHS depicts this plume of moisture and associated instability will back into New Mexico this evening. Could it play a part in tomorrow’s severe weather risk?

Here is what happened at El Paso when the front backed into the area – Dewpoint jumped from 30F to 50F

– David Spritz

– Mr. Bean

Louisville KY WFO Observations During DSS


Immediately after coming online, there was the potential for heavy showers in my area of concern and a storm heading toward an established DSS Event. Initially, LightningCast showed a 50%-75% chance of lightning within the next hour, but this was monitored in successive frames as the trend continued downward.
This product gave me the situational awareness to immediately know that I should be interrogating a storm heading toward my DSS event without an in-depth analysis across multiple radar/satellite products. I continued to monitor the product as I got the rest of my AWIPS setup and I noticed the downward trend continued for my storm of concern. This simple display along with GLM flash data (on a 0-50 scale for this storm mode) gave me confidence in analyzing this as a low-end threat. This has an application in the operational shift change where a new forecaster can have two simple products loaded on a screen with rapid updates indicating that a DSS area is increasing or decreasing its likelihood of seeing lightning within the next hour. These two products in tandem are not only useful operationally, but as a base situational awareness tool.
Initial LightingCast/GLM view of the storm moving toward the DSS event area.
Visually the trend decreased after this initial probability. It would be very useful to have these plots available in AWIPS to view the increasing/decreasing probabilities associated with perceived storm growth and decay.
After the initial spike (which occurred as I was logging on), you can see that with no observed strikes and the probabilities staying constant, there was no initial concern.
The trend continued with a subsequent steady decrease in probability.
Another storm the south became the main concern with a Significant Weather Advisory (SPS) issued for its growth and subsequent wind threat. In this case, I think LightingCast is doing a good job at highlighting the advection and limiting the probabilities over my area based on its current (pictured) motion.
LightningCast and GLM plotted with a current storm motion and Time of Arrival tool to show that it is expected to miss the DSS event at this current time. However LightningCast did put the area in the 75% contour at 20:26Z
Our DSS event was impacted by a separate storm just north of this main storm at 20:33Z. There were no cloud flashes ahead of the CG strike and LightningCast did a good job of highlighting the area as potential increased at 20:26Z, but this was only a lead time of 7 minutes. After this observed CG strike, LightningCast dropped the probabilities to around 50% despite observed strikes occurring within the previously outlined 75% area. Thick clouds around the area from previous and advancing convection were observed over the entire area.
Lightning has been observed near the DSS Event ahead of any observed cloud flashes at 20:33Z. LightningCast only gave a 7-minute lead time with this quick-pulsing storm.
With lightning ongoing and observed within the 75% contour,, LightningCast dropped the probabilities to ~50% at 20:45Z.
This was the LightningCast trend at the time of ongoing, observed, lightning.
The trend remained steady after the lightning was observed and continued through the next couple of hours as the storm following this one weakened and moved over the DSS event area.


GLM performed quite well over the area today, especially as the storms were strengthening. The MFA and FED were again useful in identifying potentially stronger storms and where to focus my attention. This was again useful outside of supercellular convection. I was surprised with how well GLM performed with dense cloud cover from ongoing convection to the south and debris clouds left over from convection earlier in the day.
In dense cloud cover, MFA and FED were able to recognize an area of convection pulsing once it left my DSS event area. This could be useful in a similar situation where the organizer of an event recognizes increased lightning in their area and is looking to return to operations (most of the EMs and organizers have lightning notifications from several ground-based detection networks and frequently interrogate us about ongoing trends). I would be able to use this as a tool to see that lightning near the event is a continued concern because of potential backbuilding around a strengthening storm.
GLM suite showing a pulse in a storm near my DSS event area.
Overall, GLM was very useful in tandem with the LightningCast products for showing growth and decay in ongoing thunderstorms.
A strengthening storm to the south of my event area shows not only FED increasing, but also sees the LightningCast 75% contour expanding northward likely due to advection of the storm. The scale in this image is FED on a range of 0-50.


PHS again performed well on the 0-2 hour timeframe. The primary fields of interest were instability (CAPE, LI) and the SigTor parameter.
PHS model data with instability, LI, and SigTor. This is a model forecast of 1-hour for the 19Z time period which was initialization in our DSS simulation.
PHS was already highlighting the area of concern along a tongue of instability where storms were ongoing as of the 19Z 1-hour forecast. In subsequent frames, it shows the instability being maintained as storms move toward my DSS area despite thick cloud cover overhead. Based on previously discussed trends in observed lightning, it seemed it was accurately showing areas of marginal but sufficient instability.
One impressive feature of the PHS model was a thin line of instability on the back edge of convection. This area was a focus for several isolated thunderstorms behind the main line advancing through northern KY as of 21Z. This was a 3-hour forecast pictured above with highlighted areas of instability by low STP, highlighting an insufficiently sheared environment.
It is worth noting that within this study/testbed, we are looking in areas of Slight Risk or higher as highlighted by the SPC as our area of interest. In an operational setting, it is fairly uncommon to have severe weather events only when the area is highlighted in the Slight or higher category. Therefore, it is unlikely that the SigTor parameter would be useful outside of high-profile events. For example, at my local WFO, we have many severe weather days where we have very high CAPE, but very little in the way of shear. Since our primary concern is usually wind, I don’t think SigTor would be useful. It may be worth adding additional parameters highlighting various threat potentials (wind, hail, etc.).

ProbSevere v3

I was not the warning forecast in this instance, but I did notice that a couplet of rotation was observed on the MRMS rotation tracks. Based on radar data (it is worth noting that this storm was at a large distance from the radar), the couplet was well within the bounds of a rotating couplet with vertical continuity and frame-to-frame consistency.
However, ProbSevere only had a tornado probability of around 10% which should have been higher given the available radar data. This couplet was short-lived, but survived for a few frames after its initial detection. Probabilities did increase, but were not high enough for what I would have expected to be a weak tornado given the surrounding data.
ProbSevere 4-panel showing overall severe potential, hail, wind, and tornado probabilities. According to the data, all of the probabilities remained low, including TOR which should have been higher in this case. This is also supported with MRMS rotational measurements and KLVX radar data.

Optical Flow Winds

With the widespread convection across my area and the long-term cloudiness, I did find some correlation between the Optical Flow Winds and the strongest storms over my CWA (LMK). This was similar to the Birmingham area yesterday, but the stronger storms were not as pronounced in yesterday’s case. CAPE profiles were a little more pronounced today across central KY which likely contributed to this advantage. However, it was still hard to pick out the exact divergence value with these storms, but there were obvious hot spots that helped with situational awareness.
The strongest divergent cells were more obvious on the OFW display today and they lined-up with the strongest cells across the LMK CWA.


NUCAPS data was unavailable today and the passes did not line-up with our area. Even if we had some data available, there would have likely been too many red-retrievals to make use of the soundings due to widespread thick cloud cover.
– Overcast Ambience

ILX Ramblings

A comparison of NUCAPS at 19Z with observed/analysis products from SPC showed good comparison for both modified and unmodified data. Below shows the unmodified NUCAPS sounding that was “green” over the north-central portion of the ILX CWA. The MLCAPE was around 500 J/kg, with DCAPE around 690 J/kg, freezing levels just below 10,000 feet, and PW’s around 1.1 inches.

A modified NUCAPS sounding for the same location showed an uptick in MLCAPE to around 600 J/kg, along with similar PW’s, DCAPE and freezing level.

A comparison with SPC mesoanalysis at 20Z showed very comparable PW values, between 1.1 to 1.2 inches over north-central IL, and freezing levels between 10 to 11 kft. As for MLCAPE, it appeared that for both modified and unmodified NUCAPS, the observed was higher than NUCAPS, around 1000-1500 J/kg, perhaps not having a high enough surface dewpoint. As for 850 mb temperatures, they were comparable to those observed, in the 12-14 degC range. DCAPE was also comparable in NUCAPS with what the SPC mesoanalysis page was showing, between 600-700 J/kg.

With regards to lightningCAST, ProbSevere, and GLM, around 1932Z, once again the LightningCast was showing good lead time for areas downstream of storms. The main cell at this time I was watching was in the southeast Part of our CWA, which had a nice contour of 75% to the north and east of that cell extending well north of the storm core.

At 20Z, the Optical Flow divergence field appeared to match up well with observed convection at this time. It thus showed quite well with the shear field.

ProbSevere’s time series graph continues to show added value, allowing the forecaster to see the trend in a storm’s severity and probability of severe potential. This image was at 20:40Z.

Around 21Z, I noticed a jump in GLM FED for the area of storms in the northwest part of the CWA. Alongside this, the GLM TOE also increased, along with a decrease in MFA with the same storm cell. This area corresponded with increased flash rates in the EarthNetworks. I modified the GLM FED scale to 20-25 as a maximum to see the activity better, as well as lowering TOE to 50 as a maximum.

Around 22Z, the GLM TOE showed a good correlation with the 3 strongest storms based on dBZ and ProbSevere, one to the north, and two in the far southeast, bordering Indiana. For this display of TOE, I lowered the contours to a max of 50, which seemed to work well.

Around 22:12Z, the LightningCast showed an uptick in probabilities of 75% north of a cell that was starting to show towering CU on the day cloud phase. This was before GLM and ground-based radar showed uptick in lightning activity.

Are the edges of LightningCast contours related to the detection of GLM? See below image…The contours do not close off.


DSS in the Birmingham CWA


The initial outlook on the PHS model shows limited potential in the CAPE and STP in this area around the DSS at 20Z. However, it shows an increased potential for 21-22Z which may be the time of most concern for my DSS area.
The initial 20Z model showing limited instability and the contoured ProbSevere to show ongoing convection.
PHS shows a tongue of instability and associated STP as the main convective line lifts northward. This would indicate that the main concern would occur around 22Z.
Based on the line of storms to the west of our DSS event and the associated shower activity lifting northward ahead of the line, the PHS model was accurately representing the convective potential. LightningCast also shows a decrease during this time period which increases consistency and confidence in what the forecaster is seeing.
This lack of convection was observed as showers moved through the area without any lightning or wind potential. There was some redevelopment behind the line and to the south of our event that indicated some concern. At 22Z, you can see the line of storms already being analyzed by ProbSevere lining up nicely with modeled instability and other plotted severe weather parameters.
ProbSevere contours and PHS model line up nicely in the 22Z 2-hour model forecast and show consistency in where the area of greatest concern is likely to be.

LightningCast & GLM for DSS

Initially the LightningCast for our DSS event surged to near 50% or slightly above. This was an initial concern for the DSS area.
As these storms weakened, the probabilities of lightning also fell to under 25%. I liked that these probability decreases were not rapid, but a gradual fall after the initial peak. GLM and LightningCast both had a consistent drop in probability and lightning activity as the “storms” weakened.
It is becoming clear that the rate of change of all of these satellite products is the most important information that a forecaster can gain. While an initial picture of the probabilities looks concerning, pairing this with other satellite products for context and seeing the overall trend of this data led to an easy decision to wait for additional data. Taking this at face value would lead to a quick (and potentially unnecessary) reaction.
Initial threat of lightning as illustrated by the LightningCast product.
The showers on the SE side of this line have decreased in intensity and have lost most of their lightning potential. The probabilities have decreased accordingly.
LightningCast, GLM, radar, and satellite showing the decreasing trend in lightning threat and the approach of moderate to light showers on the DSS event.
Showers are expected within the next 30-40 minutes and the trend in lightning appears to be going down consistently. GLM has also been helpful in showing that no cloud flashes have been observed at this stage.
There were some minor inconsistencies that I noticed since the Meso-sectors were both over our CWA. These were mostly minor, but I noticed at one point, a location had a probability of >50% or 0% and did not intersect with GLM measurements.
Inconsistencies in GLM and LightingCast Meso1/Meso2 probabilities. It seems the accurate probability here was 0% based on the lack of ground-based lightning network reporting.
As PHS indicated there was a second and more concerning wave of convection moving from the SW toward the DSS event area later in the afternoon. GLM and LightningCast probabilities both show the strengthening of this pulse and the increased lightning activity as it moved into the BMX CWA.
21:26Z, the storm indicated a 10% chance of lightning at the DSS event area.
21:36Z, the storm indicated a 50% chance of lightning at the DSS event area.
The 45-minute warning was given at 21:50Z to the event coordinator that a storm with the potential of producing lightning and winds in excess of 30 mph was approaching the event area. GLM was a key part in this decision as it continued to show strengthening with lightning pulses indicating that the storm was at least maintaining its strength. The LightningCast probabilities were also increasing as they approached the area with the 75% contour moving into the area by 21:52Z.
GLM (top) and LightningCast at the 45-minute DSS decision point.
The pulses weakened significantly as it approached the area and this was consistently evident in the GLM display and the LightningCast probabilities.
GLM (top) shows the MFA increasing and the FED decreasing. This was consistent with radar data and observed lightning pulses. The LightningCast probabilities also decreased.
Lightning occurred in the area around 22:38Z with GLM showing another pulse beginning as the storm moved through our DSS area.
In general, I found GLM to be much more useful today outside of the supercellular mode with more multicellular convection observed over central and southern AL and especially so for identifying strong cells within a linear structure.

ProbSevere v3

In a DSS setting there isn’t a real reason to use ProbSevere v3 because winds far below the 50-knot threshold could cause problems at our DSS events. That being said, there was great information in the trend graphic as I could see the growth and decay of storms that were already in progress. This allowed me to focus my attention on the strongest storms.


Ongoing convection ahead of the line of storms limited the NUCAPS ability to produce good data. Availability of soundings was also an issue as the data came in between 19-20Z with storms ongoing near my area of interest.

Optical Flow Winds

For the optical flow winds, there wasn’t much in the way of DSS that I could find a use for. The divergence field again could be useful, but with the suite of GLM I was seeing the divergence and strengthening of the storms in multiple products. Visualization is still the main hurdle with OFW.
Once the anvil for some of these storms developed it was difficult to use. Especially as debris clouds developed and overspread the area in advance of additional convection behind the initial line.
– Overcast Ambiance

Memphis, TN Synopsis


An upper low and cold front is expected to move across the lower MS Valley. As the upper low moves east today, weak shortwaves embedded in southwest flow will lead to a marginal risk of thunderstorms as they form along and ahead of the front over the Memphis region. The main concern was a moderate risk of excessive rainfall for this afternoon/evening.

IR imagery. Upper low located near the OK Panhandle.

Surface analysis map of the surface low and attendant front.

Surface observations as of 4:00PM CDT.

SPC Day 1 Convective placing TN at a marginal risk.

MLCAPE ~500 J/kg.

PHS displaying weak CAPE/LI values and a well-defined dry line just west of AR.

WFO Memphis headlining excessive rainfall outlook.

WFO Memphis headlining marginal risk of severe storms.

Most of the severe storms were east and south of our area of interest shown here with GLM.

GLM overlaid with Radar.

GLM overlaid with satellite imagery.


ProbSevere3 showing a low risk of thunderstorms.

Optical Flow winds show an area of divergence over eastern and southern AR/TN border.

Vortex Power