Friday, May 13, 2016
HWT 2016 GOES-R/JPSS Spring Experiment Complete!
The 4 week GOES-R/JPSS Spring Experiment in the HWT completed today, May 13.
Week 4 complete!
The fourth and final week of the HWT 2016 GOES-R/JPSS Spring Experiment is complete! After starting out very busy on Monday with severe weather, including tornadoes, in the Norman CWA, the week quieted down. However, we certainly still had enough severe convective weather across the CONUS Tues-Thurs to keep our participants plenty busy evaluating the satellite products.
Week 4 (9-13 May 2016) Summary and Feedback
The final week of the 2016 GOES-R/JPSS Spring Experiment concluded with our two pairs operating in the Nashville and Huntsville CWAs. Both were able to evaluate the PGLM product via the Huntsville LMA.
LAP
- Convection developed along the moisture and instability gradients in LAP.
- I liked seeing the model data where retrievals were unavailable. In addition to having a continuous field, it often allowed for quick comparisons of retrievals with nearby GFS.
- Our office does look at K-Index for flash flood situations.
- 30-min is a good temporal update frequency. Too frequent of updates would not be that useful, as such fields do not change so rapidly.
- Layer PW was my favorite LAP product as it was most unique, and added value to my analysis. It was particularly useful on days when we had strong low-level moisture advection, tracking the movement of moisture, and dry air aloft.
GOES-R CI
- When I had 1-min imagery, I did not need CI because I could identify areas of imminent CI in the imagery.
- In situations where you are expecting severe thunderstorm activity, you's look more at severe CI. Regular CI was not as useful for severe situations because you could see cb development in the 1-min data.
- When looking for general thunderstorms, I see CI being more helpful, including in the cool season. This would be valuable for DSS purposes.
- I found utility in having both CI products up. If severe CI was pinging on something in addition to regular CI, it helped to focus attention to particular areas of interest.
- It would be helpful to see probability trends for a particular cloud/area.
- We were fine with the display concept
- I like the current instantaneous visualization over a smoothed probability field approach.
ProbSevere
- It would be nice to see a meteogram with a history of ProbSevere probs.
- Everyone is fine with the display and color-scale.
- Similar to VIL of the day, might be helpful to determine "ProbSevere Prob" of the day.
- I think it really well with discrete cells, but later would merge nearby cells.
- I would say this was my favorite product outside of the 10min imagery.
- I thought it performed great this week.
- We would all use this in operations.
- I've worked 5 or 6 severe events in the last month, and I've ProbSevere up for all of them. Usually I have storm relative velocity all tilts, regular velocity in the middle, and the third screen has different fields, including composite reflectivity with ProbSevere. I've also even started putting it on all-tilts. The display does not distract me. In my office, the threshold to warn depends on the day, but I've found with most of our events, especially with severe wind, we can get severe with a threshold of ~60%. Definitely not using it as a yes/no.
SRSOR
- All forecasters loved using it this week!
- 5-min is certainly bettern than 15. But when you are tracking low-end severe situations, subtle boundaries can make all the difference between something going up or not. We get better than 5-min radar data, but 1-min satellite data can fill gaps that we still have. 5-min will be useufl, but 1-min is optimal.
- I think it is certainly time to make the jump to 1-min satellite imagery. There is so much that can be seen, even outside of convection. Forecasters need to use satellite data more in day to day operations. Generally, I think forecasters don't think satellite imagery is as useful as it is, and they have a hard time understanding exactly how much they will see in the 1-min imagery.
- It was helpful to view long loops of the 1-min imagery on the regional scale to get a big picture idea of how the system was evolving.
- It was really helpful for analyzing frontal structure and all the different boundaries.
- Satellite imagery is truly the only visual representation you have of a storm that you can't get with any other product.
- I found it useful to match 1-min lightning data with 1-min satellite data.
SRSOR Winds
- I liked the winds a lot. You could see the vertical structure of a front, and how winds changed with height from the surface. Seeing rapid change over a short vertical distance was intriguing. AMV's could be a big help with our TAFs.
- I felt that the low-level winds were more useful than the upper-level winds. They indicated areas of low-level convergence, moisture transport, veering of winds from the surface, potential for tornadoes.
Lightning Jump
- I liked it more as the week went on. I usually used it in tandem with ProbSevere and PGLM Flash Extent Density. I could see all of these being in a 4-panel and helping with situational awareness for severe operations. Especially on Thursday, I noticed the storms with the biggest LJ's were the ones that strengthened considerably thereafter.
- I'll be interested to use this during cool season events, as I am always looking for more information in these situations.
- I like the way it is now, though I can see others preferring a contoured look.
- I like a 4-panel layout with ProbSevere, lightning jump, Severe CI, Lightning, composite reflectivity, and satellite imagery.
- Forecasters are/will always change to their preferred color tables.
- There will always be a spot for a product like Lightning Jump in my display.
GLM Total Lightning
- The lightning data will be very helpful for DSS - events, fairs, etc. It will be very helpful to have this information updating every 1 minute.
- Especially for cool season events, we are always looking for more data. Lightning from satellite will be helpful.
- I can see this being helpful in EM's decisions to evacuate stadiums.
- This will be big for us during fire weather season in the NW US.
- In the future, with lightning in field offices, there must be very good training on all of this. There is/will be a lot of different lightning data. Generally, forecasters do not know the differences in lightning verbage.
- I will likely overlay it on radar or satellite.
- LMA-1 was the favorite among the group
NUCAPS
- The plan view and cross-section components were my favorite aspect of NUCAPS this week
- The lure is that it is an observation. I think it should remain observationally driven, even though we know there could be a source of error. If so, we know the source of the error. If you add in model data, you don't always know the source of the error.
- Pop-up skew-T will be good to use before and during an event with NUCAPS.
- Modification is not an issue for me. In our office we modify RAP soundings all the time. It takes some time, but it works.
- NUCAPS has a lot of potential, but a lot of bust potential for captivating an office.
- I can't get anyone to look at it in my office in Portland.
- The lack of detail is a killer. That's why I think plan view and cross section displays are more valuable.
- People will use it if they see the value, and it is made clear that this is an observation.
General
- Participants felt that the start of week orientation/familiarization was great.
- It was the perfect amount of products to evaluate.
- It would be nice to have a DRT WES case for slow days.
- I suggest having a group briefing after the groups complete their mesoscale analysis but before CI.
- The broadcaster commented that this was a great experience, and it was wonderful to be able to work directly with NWS forecasters.
- Some of the training material should be put on the CLC so we can go back and look at it in the future.
LAP
- Convection developed along the moisture and instability gradients in LAP.
- I liked seeing the model data where retrievals were unavailable. In addition to having a continuous field, it often allowed for quick comparisons of retrievals with nearby GFS.
- Our office does look at K-Index for flash flood situations.
- 30-min is a good temporal update frequency. Too frequent of updates would not be that useful, as such fields do not change so rapidly.
- Layer PW was my favorite LAP product as it was most unique, and added value to my analysis. It was particularly useful on days when we had strong low-level moisture advection, tracking the movement of moisture, and dry air aloft.
GOES-R CI
- When I had 1-min imagery, I did not need CI because I could identify areas of imminent CI in the imagery.
- In situations where you are expecting severe thunderstorm activity, you's look more at severe CI. Regular CI was not as useful for severe situations because you could see cb development in the 1-min data.
- When looking for general thunderstorms, I see CI being more helpful, including in the cool season. This would be valuable for DSS purposes.
- I found utility in having both CI products up. If severe CI was pinging on something in addition to regular CI, it helped to focus attention to particular areas of interest.
- It would be helpful to see probability trends for a particular cloud/area.
- We were fine with the display concept
- I like the current instantaneous visualization over a smoothed probability field approach.
ProbSevere
- It would be nice to see a meteogram with a history of ProbSevere probs.
- Everyone is fine with the display and color-scale.
- Similar to VIL of the day, might be helpful to determine "ProbSevere Prob" of the day.
- I think it really well with discrete cells, but later would merge nearby cells.
- I would say this was my favorite product outside of the 10min imagery.
- I thought it performed great this week.
- We would all use this in operations.
- I've worked 5 or 6 severe events in the last month, and I've ProbSevere up for all of them. Usually I have storm relative velocity all tilts, regular velocity in the middle, and the third screen has different fields, including composite reflectivity with ProbSevere. I've also even started putting it on all-tilts. The display does not distract me. In my office, the threshold to warn depends on the day, but I've found with most of our events, especially with severe wind, we can get severe with a threshold of ~60%. Definitely not using it as a yes/no.
SRSOR
- All forecasters loved using it this week!
- 5-min is certainly bettern than 15. But when you are tracking low-end severe situations, subtle boundaries can make all the difference between something going up or not. We get better than 5-min radar data, but 1-min satellite data can fill gaps that we still have. 5-min will be useufl, but 1-min is optimal.
- I think it is certainly time to make the jump to 1-min satellite imagery. There is so much that can be seen, even outside of convection. Forecasters need to use satellite data more in day to day operations. Generally, I think forecasters don't think satellite imagery is as useful as it is, and they have a hard time understanding exactly how much they will see in the 1-min imagery.
- It was helpful to view long loops of the 1-min imagery on the regional scale to get a big picture idea of how the system was evolving.
- It was really helpful for analyzing frontal structure and all the different boundaries.
- Satellite imagery is truly the only visual representation you have of a storm that you can't get with any other product.
- I found it useful to match 1-min lightning data with 1-min satellite data.
SRSOR Winds
- I liked the winds a lot. You could see the vertical structure of a front, and how winds changed with height from the surface. Seeing rapid change over a short vertical distance was intriguing. AMV's could be a big help with our TAFs.
- I felt that the low-level winds were more useful than the upper-level winds. They indicated areas of low-level convergence, moisture transport, veering of winds from the surface, potential for tornadoes.
Lightning Jump
- I liked it more as the week went on. I usually used it in tandem with ProbSevere and PGLM Flash Extent Density. I could see all of these being in a 4-panel and helping with situational awareness for severe operations. Especially on Thursday, I noticed the storms with the biggest LJ's were the ones that strengthened considerably thereafter.
- I'll be interested to use this during cool season events, as I am always looking for more information in these situations.
- I like the way it is now, though I can see others preferring a contoured look.
- I like a 4-panel layout with ProbSevere, lightning jump, Severe CI, Lightning, composite reflectivity, and satellite imagery.
- Forecasters are/will always change to their preferred color tables.
- There will always be a spot for a product like Lightning Jump in my display.
GLM Total Lightning
- The lightning data will be very helpful for DSS - events, fairs, etc. It will be very helpful to have this information updating every 1 minute.
- Especially for cool season events, we are always looking for more data. Lightning from satellite will be helpful.
- I can see this being helpful in EM's decisions to evacuate stadiums.
- This will be big for us during fire weather season in the NW US.
- In the future, with lightning in field offices, there must be very good training on all of this. There is/will be a lot of different lightning data. Generally, forecasters do not know the differences in lightning verbage.
- I will likely overlay it on radar or satellite.
- LMA-1 was the favorite among the group
NUCAPS
- The plan view and cross-section components were my favorite aspect of NUCAPS this week
- The lure is that it is an observation. I think it should remain observationally driven, even though we know there could be a source of error. If so, we know the source of the error. If you add in model data, you don't always know the source of the error.
- Pop-up skew-T will be good to use before and during an event with NUCAPS.
- Modification is not an issue for me. In our office we modify RAP soundings all the time. It takes some time, but it works.
- NUCAPS has a lot of potential, but a lot of bust potential for captivating an office.
- I can't get anyone to look at it in my office in Portland.
- The lack of detail is a killer. That's why I think plan view and cross section displays are more valuable.
- People will use it if they see the value, and it is made clear that this is an observation.
General
- Participants felt that the start of week orientation/familiarization was great.
- It was the perfect amount of products to evaluate.
- It would be nice to have a DRT WES case for slow days.
- I suggest having a group briefing after the groups complete their mesoscale analysis but before CI.
- The broadcaster commented that this was a great experience, and it was wonderful to be able to work directly with NWS forecasters.
- Some of the training material should be put on the CLC so we can go back and look at it in the future.
Thursday, May 12, 2016
SRSOR Sandwich
Below is a SRSOR 1-min-updating animation of visible imagery with transparent IR imagery overlaid. This imagery depicts the line of convection moving into the Southeast, through our area of operation today (Huntsville and Nashville). This image combination allows forecasters to view rapidly changing storm-top features with the detail of the higher-res visible imagery and ability to see/sample temperature from the IR imagery.
Using Pop-up Skew-T with NUCAPS
Pop-up skew-T is a feature in AWIPS that allows forecasters to quickly visualize temperature and moisture profiles on a skew-T diagram from model-derived or observed sources. The user has the ability to move their mouse over a field and see the profile change in space. This is of particular use for NUCAPS, allowing a forecaster to get a quick look at the profile before clicking it and interrogating it further. See instructions and images below to use pop-up skew-T in AWIPS-II with NUCAPS.
1) Load NUCAPS Sounding availability (so you know where the
swath is).
2) Load pop-up skew-T (top of "Volume" menu)
3) Turn on Sampling
3) Right click and hold anywhere in the screen, hover mouse
over "Sample Cloud heights/radar skew T" at top of menu, Select
NUCAPS. (see image 1). A Skew T box will appear somewhere on you screen.
4) Move mouse into NUCAPS swath to see temp/mois profile change
in space (see image 2).
Pop-up skew-T for AWIPS
The Pop-up skew-T feature in AWIPS works for NUCAPS. This feature allows forecasters to quickly view soundings from NUCAPS before interrogating them further in NSHARP.
Mobile, AL had a special 18z radiosande launch today (shown below). The profile reveals a moist layer below 700 mb, with a dry layer centered around 400 mb. SBCAPE in the sounding is about 2100 j/kg, while TPW is 1.5 inches.
A modified NUCAPS sounding was sampled over the same location. The sounding depicts a similar moist low-layer, with a dry layer around 400 mb. CAPE is about 2200 j/kg, and TPW is 1.36 in, both similar to that from the observed radiosande.
Mobile, AL had a special 18z radiosande launch today (shown below). The profile reveals a moist layer below 700 mb, with a dry layer centered around 400 mb. SBCAPE in the sounding is about 2100 j/kg, while TPW is 1.5 inches.
Final Thoughts 5/12/16 HUN
Final thoughts on the day. Today was a huge success for the PGLM. Looking at flash densities for storms in the Huntsville area was highly beneficial. I liked that the output was not tied to the cells and also I preferred the smoothing on the product. As I was not really interrogating it like I would radar data, smoothing was preferred and I could see easily exporting this to an emergency manager or social media post.
Atmospheric vectors did a great job of showing the structure of the pre-frontal trough in the vertical.
1 minute data was vital in tracking the speed of the prefrontal trough, outflow boundaries and the front itself as the afternoon evolved. As always, tracking overshooting tops was beneficial to the warning process and also to monitor storms as they were decaying as well.
NUCAPS did well with the soundings and was also impressed by the theta-e cross section presented across the frontal boundary. While some observational data still needed to be modified, I could see this data being highly useful in the office.
ProbSevere was understandably lower today in this environment but qualitatively the worst cells had the highest probsevere ratings. As a forecaster, this was still a useful product to have today.
CI didn't have a chance to present itself today as convection had already initiated before the session began. - Jason Bourne
Atmospheric vectors did a great job of showing the structure of the pre-frontal trough in the vertical.
1 minute data was vital in tracking the speed of the prefrontal trough, outflow boundaries and the front itself as the afternoon evolved. As always, tracking overshooting tops was beneficial to the warning process and also to monitor storms as they were decaying as well.
NUCAPS did well with the soundings and was also impressed by the theta-e cross section presented across the frontal boundary. While some observational data still needed to be modified, I could see this data being highly useful in the office.
ProbSevere was understandably lower today in this environment but qualitatively the worst cells had the highest probsevere ratings. As a forecaster, this was still a useful product to have today.
CI didn't have a chance to present itself today as convection had already initiated before the session began. - Jason Bourne
Final Convection thoughts with the pGLM
At 2310 UTC, a broken line of convection continues from south of Nashville, TN into northern AL, and northern MS. The ENTLN shows the 5-min total LTG with the individual cells in the broken line. The pGLM shows the various color tables for the Flash LTG density at 2310 UTC. From a pure visualization perspective you can see the benefits of the pGLM in a procedure to assist a forecaster with convection forecasting, whether it is for general convection or severe. This blogger still thinks the upper right color table is the best to show the flash extent density from the pGLM.
-Yodamaster777
1 Min Vis Satellite: Normal image vs. parallax-corrected image
In addition to the 1 minute visible satellite imagery, we also had access to a parallax-corrected version of the product this week. It was interesting to compare the two images.
Below are 2 images centered over northern Alabama. There are several overshooting tops apparent on developing cells. Comparing the locations of the centers of the overshooting tops, I found that the the regular and the parallax-corrected images differed by around 8-10 miles. This could make a significant difference if a forecaster was using an overshooting top to try to center a warning track.
Note: I also discovered today that overlaying lightning flash density from the pGLM network on top of the satellite imagery was a nice display. In this case, you can see that the higher flash densities better correspond to the overshooting tops on the parallax-corrected image. - JP
Normal visible imagery
Parallax-corrected visible imagery
Below are 2 images centered over northern Alabama. There are several overshooting tops apparent on developing cells. Comparing the locations of the centers of the overshooting tops, I found that the the regular and the parallax-corrected images differed by around 8-10 miles. This could make a significant difference if a forecaster was using an overshooting top to try to center a warning track.
Note: I also discovered today that overlaying lightning flash density from the pGLM network on top of the satellite imagery was a nice display. In this case, you can see that the higher flash densities better correspond to the overshooting tops on the parallax-corrected image. - JP
Normal visible imagery
Broadcast media perspectives of new products
This week I was lucky enough to experiment with tools and products that will help forecasters make faster and more accurate decisions regarding severe weather. As someone who works on the TV side of things, I have a different view of how useful these products could be to me and my colleagues. While the forecasters main goal is to issue timely warnings to save lives and property, my goal is to quickly and clearly communicate warnings and threats to the public, via tv, social media. etc... .
While ALL the products are valuable, there are several which I would think would be most beneficial to me if I had them available to me to share with viewers
1 minute VIS. Satellite- Total eye candy...after all I work in a visual world. The stunning displays would give our viewers something to look at, and I could point out certain features that concerned me (rapid development etc...).
Lightning Jump- Another one of my favorite visual tools. I would use a modified version of this, and obviously the language wouldn't be "sigma". I could however imagine a version of this where the categories were small-moderate-large-extreme...or negative. It would be easy to communicate quickly that if we see these jumps, that means the potential is there for severe storm development, or at least these storms warrant close watching. Once storms reach severe levels I'm not sure I would continue to use that tool. I believe I would switch at that point to PGLM.
PGLM- I would use this tool to track severe storms and show the lightning. We currently show lightning flash counts, and the viewers love it, but I would prefer the visual display presented as it is in PGLM.
PROB Severe- Initially I was ALL FOR IT. I loved the outline display. After tracking storms in the Southeast today where the product under-performed due to a different atmospheric environment, an environment that is much closer to my home one, I changed my mind. If this product could be fine tuned specifically for region or season, then I would LOVE to show viewers a severe probability parameter storm cell by storm cell.
CI & CI Severe- Still unsure of the value this would have to viewers. If there were no storms present, but storms expected I could see this being something that could help show storm potential, but I would want to have higher confidence in the product. I would probably also only want to show probs of 80 or higher on air.
Even though I wouldn't necessarily use the assessment products on air (LAP, NU CAPS) I am glad that NWS forecasters will have these available because I see their value as well.
-StormFront
While ALL the products are valuable, there are several which I would think would be most beneficial to me if I had them available to me to share with viewers
1 minute VIS. Satellite- Total eye candy...after all I work in a visual world. The stunning displays would give our viewers something to look at, and I could point out certain features that concerned me (rapid development etc...).
Lightning Jump- Another one of my favorite visual tools. I would use a modified version of this, and obviously the language wouldn't be "sigma". I could however imagine a version of this where the categories were small-moderate-large-extreme...or negative. It would be easy to communicate quickly that if we see these jumps, that means the potential is there for severe storm development, or at least these storms warrant close watching. Once storms reach severe levels I'm not sure I would continue to use that tool. I believe I would switch at that point to PGLM.
PGLM- I would use this tool to track severe storms and show the lightning. We currently show lightning flash counts, and the viewers love it, but I would prefer the visual display presented as it is in PGLM.
PROB Severe- Initially I was ALL FOR IT. I loved the outline display. After tracking storms in the Southeast today where the product under-performed due to a different atmospheric environment, an environment that is much closer to my home one, I changed my mind. If this product could be fine tuned specifically for region or season, then I would LOVE to show viewers a severe probability parameter storm cell by storm cell.
CI & CI Severe- Still unsure of the value this would have to viewers. If there were no storms present, but storms expected I could see this being something that could help show storm potential, but I would want to have higher confidence in the product. I would probably also only want to show probs of 80 or higher on air.
Even though I wouldn't necessarily use the assessment products on air (LAP, NU CAPS) I am glad that NWS forecasters will have these available because I see their value as well.
-StormFront
ProbSevere HUN Highest of day with Rotating Cell
2030-2250 UTC GOES-14 SRSOR MEGA-LOOP
The 1-min loop over the past few hours provides the user with the aesthetic and meteorological beauty of the GOES-14 SRSOR-1-min imagery.
For example, a short-wave can be seen over IA, with plenty of post frontal stratocumulus and cumulus over the upper Midwest, western Great Lakes Region, and IL.
Upper level cirrus, and anvil blow-off from the convection over KY, TN, and OH continues to move into the central Great Lakes Region ahead of the cold front.
Finally, the overshooting tops and cumulonimbus evolution of the strong to severe thunderstorms can be beautifully seen over the TN Valley, Midwest, and the OH Valley.
May the Force be with You!
-Yodamaster777
For example, a short-wave can be seen over IA, with plenty of post frontal stratocumulus and cumulus over the upper Midwest, western Great Lakes Region, and IL.
Upper level cirrus, and anvil blow-off from the convection over KY, TN, and OH continues to move into the central Great Lakes Region ahead of the cold front.
Finally, the overshooting tops and cumulonimbus evolution of the strong to severe thunderstorms can be beautifully seen over the TN Valley, Midwest, and the OH Valley.
May the Force be with You!
-Yodamaster777
NUCAPS Cross-Section Shows Cold Front
We learned today that we are able to look cross sections of NUCAPS data. With a cold front moving through the midwest toward the Ohio Valley today, we took a look at the 19Z NUCAPS data from the Suomi-NPP satellite pass. Below is a cross section of equivalent potential temperature (Theta E) running from northern Florida up through central Kansas.
In this image, Florida is to the right and Kansas is to the left. Based on METAR observations, the cold front was oriented over central Missouri and Arkansas at 19Z. The cold front appears to be approximately 600 km from western-most point of the cross-section. Lower theta-E values can been at the lower levels west of this point, with the isotherms sloping upward from east to west on the cool side of the frontal boundary. This is a cool way to visualize the location and structure of a frontal boundary! -JP
Very High Lightning Flash Density Animation
Here is an animation of some very high lightning flash rates with a warned storm in Northern Alabama. These flash rates were the highest of the day. After re-evaluating the color curves presented for a flash rate this high, I determined I preferred the upper right color curve. This stood out the most to me and also did not mimic the color scale from other products like the default does. This storm also had a lightning jump of 6 sigma (top right in figure 2) which was one of the highest we saw of the day. Using the PGLM and the Lightning Jump products in tandem was a great confidence booster for warnings. As far as the PGLM was concerned I like that it is not tied to the individual cell as it can give an idea of how far away from the storm that lightning can travel. I could see this being a useful visual presentation for an Emergency Manager trying to decide to evacuate a stadium full of people or not. -Jason Bourne
NUCAPS Pop-Up SKEW-T
One of the beautiful things about NUCAPS in AWIPS is the ability to view pop-up Skew-T's. One can move the cursor over the points from the Met-Op satellite. These pop-up Skew-T can give a quick-look of thermodynamic profile across the green dots. Some of the yellow dots may look good too. Overall, Pop-Up Skew-T's they rule!!!
Also, the cross-section is shown in the main-image, as the Pop-Up Skew-T is in the upper left.
-Yodamaster777
Also, the cross-section is shown in the main-image, as the Pop-Up Skew-T is in the upper left.
-Yodamaster777
pGLM Color Table Discussion (continued)
One cell in the northern portion of Huntsville's forecast area produced a tremendous amount of lightning in the last 2 mins.
At 2200 UTC, the pGLM Total lightning rate increased significantly for near full usage of the color tables. After further review, the upper right looks like the best one transitioning from cool to warm colors, and then back to cool.
The cell at 2216 UTC started to produce over 120+ flashes per 2 minutes with a transition to white colors in all the color tables. I like the lower left less now, and like the right two panels more.
At 2218 UTC, my final thoughts are the upper right "takes the cake", as my favorite color table for the HWT GOES-R testbed.
-Yodamaster777
At 2200 UTC, the pGLM Total lightning rate increased significantly for near full usage of the color tables. After further review, the upper right looks like the best one transitioning from cool to warm colors, and then back to cool.
The cell at 2216 UTC started to produce over 120+ flashes per 2 minutes with a transition to white colors in all the color tables. I like the lower left less now, and like the right two panels more.
At 2218 UTC, my final thoughts are the upper right "takes the cake", as my favorite color table for the HWT GOES-R testbed.
-Yodamaster777
PGLM compare and contrast
We were finally lucky enough to use the PGLM lightning tool today. I found it visually pleasing and useful. I like that fact that once you figure out the scale, it immediately conveys the severity of the lightning. For example.
I learned that anything over dark blue (in the default frame) is OVER 30 flashes.
That's all I need to know. I can tell by looking at this storm that there is a LOT of lightning. If I want to get the exact amount I can scroll over, but I don't need to. It's like a visual threshold for me. I prefer the non-pixelated version, and as far as color tables...I prefer the default. I initially chose the top right corner because it was more intuitive with red bring stronger, but the blues in the default give a very clear demarcation of major vs. minor lightning.
-StormFront
That's all I need to know. I can tell by looking at this storm that there is a LOT of lightning. If I want to get the exact amount I can scroll over, but I don't need to. It's like a visual threshold for me. I prefer the non-pixelated version, and as far as color tables...I prefer the default. I initially chose the top right corner because it was more intuitive with red bring stronger, but the blues in the default give a very clear demarcation of major vs. minor lightning.
-StormFront
Random Michigan storm
A storm in lower Michigan stood out from a line of weak to moderate convection, thanks to increasing severe probability from the NOAA/CIMSS ProbSevere model. The storm, which was outside of the SPC marginal severe outlook, had steadily increasing MRMS MESH and flash rate before the warning was issued, at 21:42Z. ProbSevere was ≥ 50% fourteen minutes prior to the warning and ≥ 80% 4 minutes prior to the warning. Every other identified storm in Michigan had a probability of 5% or less. So far, no reports have been received.
 |
| Fig. 1: ProbSevere contours, MRMS composite reflectivity, and 5-min NLDN CG flashes in AWIPS2. Notice how this storm clearly stands out from all of its neighbors in the state |
 |
| Fig. 2: KDTX base reflectivity and severe thunderstorm warning. |
CI Shows Additional Convective Threat With Trailing Cold Front
The main band of showers and thunderstorms has mostly cleared the Nashville CWA at this point. However, the CI algorithm has been highlighting convective potential along the pre-frontal trough and then along the trailing cold front later this afternoon and this evening. The CI values have been fairly modest, and the severe CI are low, so we are not expecting the additional showers moving in over the next few hours to be all that strong.
MRMS mosaic 0.5 deg. radar is now showing some better developed echoes associated with the pre-frontal trough draped from western TN down through northern MS and south AR. There are also some weak echoes showing up from south IL down through the MO panhandle associated with the cold front. -JP
MRMS mosaic 0.5 deg. radar is now showing some better developed echoes associated with the pre-frontal trough draped from western TN down through northern MS and south AR. There are also some weak echoes showing up from south IL down through the MO panhandle associated with the cold front. -JP
pGLM Color Tables Thoughts
The activity has been kind of quiet over OHX forecast area. However, here are some thoughts on the pGLM color tables.
Preference is for the color table in the upper right or lower left. They work the opposite from each other going from warmer to cooler colors in the lower left panel, and cooler to warmer colors in the upper right. I do not like the color table in the upper left panel, since it is an AWIPS default color scheme for other convective parameters such as CAPE, stability indices, etc. The lower right is decent but goes from gray-scale to cooler colors, and then to the warm or HOT colors. It might take some time to make this jump.
-Yodamaster777
Preference is for the color table in the upper right or lower left. They work the opposite from each other going from warmer to cooler colors in the lower left panel, and cooler to warmer colors in the upper right. I do not like the color table in the upper left panel, since it is an AWIPS default color scheme for other convective parameters such as CAPE, stability indices, etc. The lower right is decent but goes from gray-scale to cooler colors, and then to the warm or HOT colors. It might take some time to make this jump.
-Yodamaster777
AMV depict pre-frontal trough
Atmospheric Motion Vectors are nicely illustrating the pre-frontal trough across Arkansas. Of particular interest is the illustration of the trough with height. For the low level winds (blue) the pre-frontal trough can be seen clearly...particularly in northeast Texas where southwesterly winds are occuring ahead of the trough and northerly winds behind the trough. Looking at upper level winds however (green, red, pink), most remain in a southwesterly direction, indicating that the trough aloft remains to the northwest. This makes sense because the frontal boundary will be tilted with height back towards the northwest. The screenshot is below. - Jason Bourne
1-minute satellite capturing front and pre-frontal trough
Looking at 1-minute imagery west of the HUN CWA the approaching cold front and pre-frontal trough are clearly visible and can be tracked with the data. The northeastern edge of the pre-frontal trough is moving into the HUN CWA and extends south and west through Mississippi and into Arkansas and Louisiana. Behind it...the actually cold front signaled by a drop in dewpoints is moving through central Arkansas. Surface observations are overlayed for illustration. Below is a still shot and a .gif to show the tracking ability with the one minute data. - Jason Bourne
Using 1 minute Satellite in desicion NOT to warn
-Stormfront
PS-This storm had our HIGHEST prob. severe of the day by far. In this environment it was tempting to warn based on that alone....
Verification of first OHX warning
A couple of Severe Thunderstorm Warnings (SVR's) have been issued for the OHX forecast area. The first warning verified at 1934 UTC with several trees down, some that fell down on homes. The following images show a rear inflow notch with a velocity max of 60 kts. This SVR was issued at 1923 UTC with an 11-minute lead time.
Prob Severe Qualitatively Helpful
With a low shear, low mid-level lapse rate environment today...ProbSevere has not been very high, and most storms have not been severe. However with the severe storm we did have...Prob Severe only topped out at 25%. This may seem like a poor performance however, when looking at ProbSevere qualitatively and not quantitatively a survey of the storms at the time showed every other storm less than 10 percent. That means that for the severe storm, despite having a low value of ProbSevere, it was still 2.5 times that of any other storm in the area. This still is useful information given the environment and actually added confidence to the warning decision because it was the best we had seen all day.
-Jason Bourne
-Jason Bourne
Lone storm in Arkansas
One lone storm in southern Arkansas along a sagging cold front jumped in ProbSevere values (40%->50%->74%->90%), due to a strong normalized satellite growth rate, and a jump in total flash rate. This storm was just outside the SPC's wind and hail outlook.
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| Fig. 1: Strong ProbSevere values on an isolated storm in southern Arkansas. |
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| Fig. 2: Our storm in southern Arkansas with the western edge of the SPC severe wind outlook (5%). |
OHX: Severe Thunderstorm Warning
Our first warning for the day was issued northeast of the city of Nashville, where a jump occurred with the pGLM data. The SVR TSRA polygon was overlayed show how the lightning jump was used in the preceding scan.
-Yodamaster777
The 4 panel below shows the Sig Probs only rose to 21%, but a distinct velocity maximum of 50-55 kts was occurring and the 1-min visibility nicely shows the strong updrafts with rapid cooling in the IR imagery. This storm was was likely capable of damaging winds.
-Yodamaster777
1 Min Visible Sat Shows Convection Developing on Outflow Boundary
We noticed an outflow boundary moving into our CWA from the Huntsville CWA to our south. Convection is developing along this line and is producing several cells that are generating quite a bit of lightning activity.
We issued a severe thunderstorm warning on one of the cells for Coffee, Warren, and Grundy conties that produced a significant lightning jump. The flash extent density value reached around 40. -JP
We issued a severe thunderstorm warning on one of the cells for Coffee, Warren, and Grundy conties that produced a significant lightning jump. The flash extent density value reached around 40. -JP
PGLM and 1-min Overshooting top HUN
Captured a good shot of 1 minute imagery with an overshooting top in the warning box. This was a good example of a line of storms moving to the northeast that all looked fairly equal for a while. Then there was this overshooting top that corresponded with a jump in the flash rate the corresponed well. In the end there was a report of quarter size hail with this storm but it was in a county that was in the far southeastern flank of the warning polygon. This did not line up with the storm but the blowoff from the storm is travelling to the southeast. It could be possible that hail from this storm was blown southeastward out of the storm and thus landing in the adjacent county. Or it could have been a suspect report. -Jason Bourne
NUCAPS theta-e Cross Section
PGLM performance in HUN
I issued a warning for a storm in a line in the NW part of the HUN CWA. The PGLM performed very well showing higher flash densities as the storm grew. Overlaying my warning polygon on the storm you can see how the flash rate was increasing and was highest at the point of warning issuance. After that time the flash rate decreased until the warning was cancelled. I was not warning based on the PGLM but it was a confidence booster and even though the storm did not end up going severe...it certainly helped the warning process in both the decision to warn and the decision to cancel the warning earlier. As a cosmetic comment I prefer the original color table but either one of the top two color scales would be fine. I do not like either of the bottom two as they are not an intuitive progression. - Jason Bourne
May 12, 2016: NUCAPS sounding
The NUCAPS sounding used today from MetOp IASI satellite turned out a bit more unstable than expected when modified with a SFC T=78F and SFC Dewpt=68F. The SBCAPE was 2681 J/kg which was a little on the high side compared to the RAP and LAP data. I think the problem today is the midlevel lapse rates are much more steeper compared to the 12Z KBNA sounding (6.8C/km). This is the sounding below.
pLGM Lightning Data
We are finally in a CWA with pLGM lightning data today and the network is actually working! Convection hasn't been all that impressive so far today, but we did have one cell that produced a pea-sized hail report. The report was from Davidson County. The pLGM lightning flash extent imagery showed a spike to around 30-40 as the cell entered Davidson County. The LMA_1 color table highlighted this jump the best, I thought.
We also noticed the ProbSevere algorithm jumped rapidly from less than 10% up to 80% in less than 10 minutes around this time. This jump seemed to be mainly triggered by the increase in lightning activity. Luckily, we did not pull the trigger on a warning based on the ProbSevere algorithm, because the storm weakened again pretty quickly after this. The shear environment is fairly weak and does not seem able to support anything other than pulse cells at this point.
- JP
HUN Mesoanalysis 5/12/16
Soggy environment in place in HUN this afternoon as almost 1.5 inches of PW is in place and LAP layered PW shows that this pretty much extends through the entire column but the wettest levels below 700 mb. This is confirmed on both a RAP sounding in the area and the NUCAPS sounding. After modification...NUCAPS did very well despite the amount of moisture in the column. A comparison of the NUCAPS and the RAP soundings are below.
Looking at a wide angle of 1-minute satellite data...a cold front can be seen pushing through Arkansas with the wind shift ahead of it approaching the Mississippi border. This line should be the focus of convection later this afternoon with a more linear structure as this is where the highest shear values are. Further east...storms firing are more instability driven at this time with almost 3000 J/kg of cape across the area. That being said...low level lapse rates are very strong but mid levels are very weak and storms are having a hard time gaining any height. With the freezing level around 11 kft...severe hail will be hard to get in this scenario.
Looking at storms on the radar now...a storm over north central Alabama has had a flash density of 60 flashes / 2 min. Short term models have this first batch of convection exiting the area after 21z and then another line with the front coming through after 23z. Main threat of the day will be wet microbursts with some small hail possible. Not much shear in place at the moment so any kind of tornadic activity seems unlikely.
-Jason Bourne
Looking at a wide angle of 1-minute satellite data...a cold front can be seen pushing through Arkansas with the wind shift ahead of it approaching the Mississippi border. This line should be the focus of convection later this afternoon with a more linear structure as this is where the highest shear values are. Further east...storms firing are more instability driven at this time with almost 3000 J/kg of cape across the area. That being said...low level lapse rates are very strong but mid levels are very weak and storms are having a hard time gaining any height. With the freezing level around 11 kft...severe hail will be hard to get in this scenario.
Looking at storms on the radar now...a storm over north central Alabama has had a flash density of 60 flashes / 2 min. Short term models have this first batch of convection exiting the area after 21z and then another line with the front coming through after 23z. Main threat of the day will be wet microbursts with some small hail possible. Not much shear in place at the moment so any kind of tornadic activity seems unlikely.
-Jason Bourne
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