Satellite HWT Day 4 Carl

Satellite HWT Day 4 Thoughts

Octane Direction

During my initial afternoon analysis I noticed a good use case for the directional product in identifying how different air masses may be coming together over the CWA. In the directional product below, we can see the magenta showing the moist surface air mass that is advecting up from the SE into west Texas and western NM. A drier air mass that is creating a bit of a dry line is pushing from the west in the more yellow colors, with some glaciating cu noted within the Day Cloud Phase RGB. Elevated convection that is still persisting from overnight can be see pushing to the southeast in the lower right, giving the more green colors. This provided a very clear and quick way to pick out these different air masses that will be the main players later in the afternoon for potential convection.

MoistGradConv RGB ECONUS

Some really interesting features that stood out when looking at this imagery during the afternoon today. Notice the sharp gradient in the light vs dark greens running across Texas, starting in the southern pandhandle near the NM border and then running SE through central parts of TX. When overlaid with 24 hour MRMS precip, you can see a clear boundary between the areas that received rain last night (the panhandle, darker greens) and the area that did not (lighter green in the Big Bend areas). This clearly stands out in the Snow/Ice NIR band which makes up a portion of the RGB. Moisture can also be seen pooling in west Texas as it moves northwestard along the edge of the Mexican Plateau. Obs later in the day showed that the “brighter” area was mixing out a bit faster given the lack of soil moisture. Some good potential situational awareness being combined within the RGB, given the ability of this to also pick out things like the dry line a little bit easier.

ProbSevere v3

Issued a warning in an area of pretty poor radar coverage (lowest tilt height was around 15kft). MRMS was still capturing a good bit of the freezing level to -20C isothermal levels, so ProbSevere was running pretty strongly with hail probabilities. Additionally, there were some significant bursts of cooler cloud tops, and the Octane product began to show some of the stronger “divergent” signatures that we had seen throughout the week as well as highlighting a clear AACP, all signs of a stronger updraft capable of keeping hail lofted.

Given the environment, these products definitely gave me additional confidence and potential lead time, given these cores really grew tremendously about 15 minutes later, including an eventual split and right mover that likely produced some large hail (hard to verify in this area given lack of population).

More Octane (Speed)!

Another picture from later of how this storm grew and exploded. Octane was showing yet another AACP. A very interesting feature of this is that Octane speed algorithm does seem to be “tracking” the AACP in a way. There are a lot of research groups out there that have been looking at ways to track these features for injections of tropospheric moisture into the stratosphere among other things, so this could be a novel way at looking at that problem.

An hour or so later, we can see how the Octane product can be used to see that a storm was weakening. The deep blue divergent signature began to quickly fade, an indication that the updraft wasn’t as strong as it was previously. Given this is data flowing in from the mesoscale sectors on GOES 16, we are getting one minute updates, which will give some lead time over analyzing the core of the storm via the radar or MRMS which needs to get the radar data and then process it. This can be important for SVS or considerations for a downstream severe. I ended up still issuing a downstream severe, but was able to use what I was seeing in the product with the weakening trend to decrease the expected hail size. MRMS and ProbSevere trends closely followed, moving downward in severity.

Above: Weakening trend starts around 22Z for the Octane Speed product in the top left

Below: ProbSevere and MRMS trends begin to come down around 22:05Z or so, lagging the above by a few minutes. Every minute counts in lead time.

-Carl Coriolis

NUCAPS Low Level Lapse Rates Compared to RAP in Convection

The 19Z NUCAPS sounding pass went over Florida as convection was ongoing across much of the state. The 850mb to 700mb lapse rate product picked up on some of the convective overturning in southern Florida where lapse rates were far less steep than other portions of the state (indicative of cooler low levels), as well as where low level lapse rates were a bit lower over the western coast. This lines up well with where the RAP was showing lower surface to 3 km lapse rates. Though these two levels are not completely analogous , they represent similar processes post-convection. However, the NUCAPS pass is also picking up on lower 850-700mb lapse rates over Georgia and South Carolina which doesn’t match with the lower lapse rate product from the RAP, but these areas were also not experiencing convection so the reason for this could be due to other factors.


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.


PHS and GLM Data for Tampa Florida this Afternoon and Evening

General Risk for Thunderstorms in Florida this Afternoon and Evening

The Tampa CWA is in a general risk for thunderstorms this afternoon and evening per the SPC.

The main potential impacts are frequent lightning, heavy rainfall, and gusty winds thanks to decent amounts of SBCAPE.  Localized flooding  also remains possible, especially in urban areas,  due to slow storm motion as PHS shows no 0-6 km Bulk Shear over Florida. This matches well with the latest SPC Mesoanalysis which also shows no 0-6 km Bulk Shear shear over the region.

NUCAPS showing SBCAPE values at 21Z. Values are highest across the central and southern portions of the Tampa CWA. Areas in green had values around 1600-1700 J/kg. Areas in teal show values ranging from 800-1400 J/kg. Areas in purple range from 200-300 J/kg.  PHS shows a similar trend to NUCAPs with higher areas of SBCAPE across the central and southern CWA with lower values across the northern half of the CWA. However, the color scale on the online version of PHS is difficult to interpret as the gradient ramps up from light red to dark red. So, you cannot really pinpoint specific values of SBCAPE. However, you are able to see areas of lower SBCAPE and areas of higher SBCAPE at a glance. 

ProbSevere version 3 increases our confidence that storms will remain generally sub-severe as ProbSevere values are below 10% across the Tampa CWA as of 1930Z.The Octane Speed Sandwich product further confirms that storms are remaining below severe limits as the strongest storms are noted over southeastern Florida this afternoon as of 1930Z. Not only do these products help us pinpoint areas of potential severe weather, but they also help us pinpoint areas of sub-severe weather.  GLM shows lightning activity increasing across the Tampa CWA early this afternoon, and activity is expected to gradually increase in coverage as more thunderstorms develop through the late afternoon and early evening hours.  Lightning Cast around 1930Z shows lightning probabilities increasing across the Tampa CWA over the next hour. Pink contours represent a 75% chance of lightning in the next hour. Green represents a 50% chance, teal a 20% chance, and dark blue a10% chance of lightning in the next hour. GLM showing lightning activity increasing across Florida from 1930Z through 2016Z across the Tampa CWA. Areas showing more oranges and yellows have shorter flashes and more lightning density. These areas help us know where stronger updrafts are located. The strongest updrafts at the time of this loop remain outside of the Tampa CWA.  -Dwight Schrute

Using GLM to track thunderstorm life cycles

GLM FED/MFA RGB here shows the rapid thunderstorm life cycles in the weakly sheared but highly unstable Florida atmosphere, as reds to yellows (intensifying convection with lots of short cloud flashes) give way to blues and purples (weakening convection with fewer but longer flashes). The range rings circle today’s DSS event, which also highlights the difficult nature of producing storm by storm headlines or products for public safety as the life span of these thunderstorms are brief. The messaging for today highlights the consistently sporadic lightning threat for anyone on the coast or at the DSS site while storms build and collapse over a matter of minutes.


Using GLM to decide to issue an SPS

GLM RGB showed the progression of a developing storm near the TBW DSS site this afternoon. Not only was lightning a threat communicated to the DSS site, but KTBW radar depicted a downburst signature as shown below, which prompted us to issue an SPS for wind to around 40 mph, frequent lightning, and heavy rain.  track a developing storm near the Florida State Fair


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


Afternoon High Plains Convection in Southern Colorado

Today we focused on the Pueblo, Colorado  CWA for afternoon High Plains convection. Scattered convection developed across the CWA leading to large hail and damaging winds. The first Severe Thunderstorm formed on our CWA border with Albuquerque and drifting south into their CWA. A second Severe storm developed and tracked north towards our DSS Event in Pueblo, bringing the potential for large damaging hail and strong winds.

15Z PHS MUCAPE valid at 18Z showed around 2000  to 2500 J/kg for green areas while areas in blue had roughly 1000 to 2000 J/kg.
SPC MUCAPE Mesoanalysis valid at 18Z shows similar trends to the 15Z PHS MUCAPE values.

16Z PHS valid at 21Z showed a slight upward trend of MUCAPE in the eastern half of the CWA. 

21Z SPC Mesoanalysis showed increasing values of MUCAPE developing just south-southeast of the CWA, similar to the 16Z run of the PHS shown above. 


15Z PHS STP valid at 18Z showing little overall threat for tornado concerns through early afternoon, for the most part values were less than 0.25. 

SPC Mesoanalysis page showing 18Z STP values similar to the 15Z PHS forecast. 

The image below shows the Octane Speed product on the left and the Octane Direction product on the right, focusing on a cluster of activity near the Jefferson/Douglas County line in Colorado. Picked this screen capture as it showed a wide range in values, mainly for the Direction product. The Octane Speed product shows some speed shear present with the lighter speeds (darker blue, ~5 kts) transitioning to brighter green/a bit of yellow (~30 kts). The magnitude of directional shear was higher, showing direction of motion/divergence ranging from ~170 degrees (core of red area) to ~295 degrees (core of green area).
Below is a animated graphic showing the transition in both products. 


Chose to grab this Octane Direction product screen capture as it shows an elongated area of storm top divergence through central Colorado.  The red/magenta colors show direction generally from the 170-190 degree range, while the green/yellow colors show values from the 275-285 degree range. The black areas are spots of data dropout, which can occur when the speed shear product drops below 5kts.


First Severe Thunderstorm Warning issued for this area today came right after 20Z, based on ProbSevere values/time series as well as the Octane Speed Sandwich product.  Probabilities ramped up quickly for both ProbSevere and ProbHail on this storm at the edge of the PUB/ABQ CWA boundary. Octane around “peak” of the storm.Low Level SRM and ProbSvr (0.5 deg slice is about 10.8k ft AGL)Mesh showing 3 inch hail on the border of the Pueblo CWA.

ProbSevere and ProbHail maxed out at roughly 90% while the storm remained severe. This storm eventually moved into ABQ’s CWA.———————————————————-

2nd Severe Thunderstorm Warning – Huerfano County

ProbSevere values and time series for 2nd Severe Thunderstorm Warning of the day, readout is at its “peak”…around 2045Z.
Octane Speed/Direction at “Peak” of the storm,  around 2045Z. Directional shear varied from ~205 degrees (reds) to ~285 degrees (greens).
ProbSevere showing the weakening trend of the storm gave us confidence that the storm was in fact weakening.  Octane speed/direction further confirming the weakening trend as colors become more diffuse in nature.

ProbSevere showing continued weakening trend. We decided not to issue another severe thunderstorm warning on this storm based on the trend.

Though this storm showed a weakening trend, it was a short-lived trend, as it still had ~2000 j/kg of MUCAPE and effective shear around 30kts to work with as it tracked farther north.

The storm ended up re-intensifying, as shown by the ProbSevere output/time series below. We went ahead and issued another Severe Thunderstorm Warning for very large hail.  An increase in both storm top speed/directional shear was also shown by the Octane product.The level reflectivity images show an impressive core peaking in the 36-40k ft range, shown in the 12.5 deg. slice. MESH showing nearly 4 inch hail south of our DSS event in Pueblo. The event was notified about the potential for large damaging hail.


-Dwight Schrute/Bubbles

Octane and ProbSvr Highlight Elko County Supercell

Octane and Prob Severe Highlight Elko County Supercell

As thunderstorms continued to mature through the afternoon, the Octane speed sandwich continued to highlight an increase in downwind velocities from an isolated supercell across central Elko County. In tandem with the increased downwind velocities, a minimum in velocities occurred on the opposing upwind side of the strengthening supercell.

ProbSevere v3 highlighted the increasing trend in severe probabilities and in tandem with the Octane speed sandwich product, and solidified the decision to keep a severe thunderstorm warning in effect for the central Elko County supercell. Prob severe values were quite a bit higher with v3 compared to v2 (see details below). The decision to not issue a tornado warning was due to the high LCL values in the region (>1,800 m AGL), despite increased ProbTor values maxing out around 17% for this supercell.


Octane speed sandwich for severe-warned storm across central Elko County Prob Severe v3 at 2028Z for severe-warned supercell across central Elko County

V-SRM-HC-SW at 2110Z for central Elko County severe-warned supercell

ProbSvr v3 at 2116Z for central Elko County severe-warned supercell – 82% v3 vs 37% v2 Probhail 73% v3 vs 30% v2; Probwind 14% v3 vs 42% v2; Probtor 17% v3 vs 2% v2