Cirrus over I-10 Cold Front, Cirrus, Anvils: Lake Charles, LA

Today was a very marginal day as a majority of the CWA was covered in cirrus and then later anvils from nearby thunderstorms. This inhibited much of the solar heating potential with the exception of a small corridor from Lake Charles to Lafayette along I-10. The thermodynamics was not impressive across the area with only 1000 to 2000 j/kg of CAPE. Much of the convective initiation relied on a weak cold front and a sea breeze. There were some thunderstorm complexes that had moved through the area which brought lightning concerns to our two DSS points. Towards the end of the afternoon we were finally seeing convective initiation along the cold front.

With clouds contaminating many of the satellite products, today was mainly focused on lightning cast, lightning stoplight, and seeing how they interact with each other. We found some issues with the stoplight product today. The stoplight product was putting an active grid box that was not co-located with the lightning strike that reported from the lightning detection system. In the image below there is a small purple cross outside of the lone red box.

Final thoughts:

Every product we worked with this week has potential to make an impact. From extending daylight rgb products using a solar zenith adjustment, to using lightning cast and lightning stoplight to help make DSS decisions. OCTANE is a massive improvement for helping to forecast the state of convection. While there are limiting factors like clouds, overall the product could quickly make an impact diagnosing convection and being able to see how correct the models are handling the shear profile. The 0.91 and 5.95 products when operational could be used as ground truth in order to identify the boundaries, and being able to compare that with the models will help with getting those first few storms correct.

-Blizzard

Tags: None

Final Ops Day – LCH

Started off the day with a cold front moving north towards the Louisiana coast. As discussed previously, GeoXO products don’t do as well with an already cloudy area, however we were able to clearly pick out where the cold front was over the gulf using the 5.15 imagery. Beyond this, I did not use this product again for ops.

Figure 1: GeoXI Imagery on top, GOES imagery on bottom

When looking at the Day Cloud Phase Distinction around 1830Z, I noticed the SZA imagery was much easier to view in terms of picking out cloud top textures vs the MesoAnywhere imagery. On the same topic of SZA, we got to see SZA really shine by looking at an area of bubbling convection that occurred around sunrise. The difference SZA made was just remarkable. In real time operations, I would’ve viewed the SZA imagery for at least 45 minutes, maybe longer, compared to what we typically use.

Figure 2: MesoAnywhere (left), SZA added (right)

Applied the Stoplight product in AWIPS today, really enjoyed using that with the Earth Networks lightning and GLM. I did observe some spatial difference between the desktop version and the version in AWIPS. I realize this could be because I approximated the range ring in the desktop viewer since there is no lat/lon input option.

 

 

Figure 3: Stoplight Desktop (left), Stoplight AWIPS (right) – 1 minute apart timestamped 18:49 and 18:50 Z, respectively

I also observed that the Stoplight expanded in coverage once storms got stronger, which increased my confidence in using this product to assist decision markers. There was a substantial jump in lightning activity highlighted by all of the lightning products, and Stoplight’s footprint expanded in response.

Figure 4: 18:41Z (left), 19:11Z (right)

LightningCast also did a great job picking up lightning potential before seeing evidence of cloud top cooling.

Figure 5: LightningCast probabilities

Finally, there were numerous cirrus clouds/anvil debris over our CWA, so we did have a more difficult timing utilizing some of the OCTANE products, but I did want to highlight that the CTC product detected areas of cooling along a boundary that was pushing away from the complex of storms into an area not obscured with anvil debris. CTC also showed the core areas of the storm where more rapid cooling was occurring.

Figure 6: OCTANE CONUS Cloud Top Cooling

-simoom

Tags: None

Overview: Week 1, Day 4

10 AM

Day 4 kicked off with another debrief session, with considerable focus on LightningCast and Lightning Stoplight for decision support. Near the end of the operations period yesterday we got the Lightning Stoplight tool into the HWT’s AWIPS-II instances (thanks to Justin, Jonny, Roger, Kris, and the rest of the Stoplight team for the hard work to get that done!). We talked about what products in AWIPS-II you could display with it, and some forecasters preferred to have the lightning information (GLM, ENTLN) while others didn’t. I’m hoping another day with DSS will better inform forecasters of these products, and using OCTANE and Synthetic GXI imagery in marginal/messy environments.

Picking our WFO locations was a bit easier today, but it was unfortunately from how limited the areas for convection were. A cold front had washed out much of the moisture and instability down to the Gulf Coast, leaving us with marginal convection from the 13 Z SPC outlook. You know it’s a meager setup when we had to request an ABI MESO domain for our area, and we were glad the SAB approved. We settled for Lake Charles, LA (LCH) and returned to San Antonio (EWX) in hopes of getting some semi-discrete convection in each. Both offices were again given two DSS events and encouraged to use the LightningCast Super Dashboards.

1PM

Operations kicked off and forecasters spent a good bit of time playing with LightningCast and the Lightning Stoplight tool together, and providing feedback to both sets of developers. Working with forecasters and developers, we made a few ‘flavors’ of the Stoplight tool in AWIPS by modifying the colorbar. Here’s the descriptions from the animation below:

  • Top left is default
  • Top right colors the flashes in the last minute as dark red
  • Bottom left changes the green to blue
  • Bottom right colors the flashes in the last minute as pink followed by a red, orange, yellow scheme

Forecasters had a positive response to the top right panel, and said that coloring the 0-1 minute flashes from GLM and ENTLN dark red in some ways removed the need to overlay those products in AWIPS, simplifying their display. I saved this display off as a procedure and hope to show future weeks and get their feedback too.

3 PM

The Synthetic GXI folks decided to show the forecasters WVT data from the METEOSAT-12 FCI, since it has the 0.91 µm band that GXI plans to add. Features such as fronts and low level moisture boundaries were identified and discussed.

4PM

We found an interesting case of CI near the Lake Charles, LA CWA, with anvil debris from upstream convection obscuring the convection from visible and infrared satellite imagery. The OCTANE cloud top cooling product had a hard time showing cooling until the updraft produced its first lightning. LightningCast v2 and v1 were also compared for their performance in this challenging scenario.

5PM
To end the day I went back and made another animation of the SZA product. This time I got sunrise over the CONUS (thanks Justin!) and showed some early morning convection across central TX, with a different cloud types and layers.

Even in the MRGL, we still had a full day!

-Kevin

Tags: None

Lots of Lightning

Got a little more time in with both LightningCast and Stoplight today being over RLX’s area. Learned today that you can add range rings in the Stoplight product. Kelley walked us through how to make adjustments to our display, such as changing the basemap and adding overlays if preferred. Feedback: One thing I noticed while using Stoplight today was I changed tabs for a little bit, came back and noticed that most of the pixels had disappeared. However when I zoomed out some, they re-appeared. I gave an early “all clear” because of this. Granted lightning was definitely on the downward trend, but once I zoomed out and the pixel repopulated, it repopulated within the 10-mile radius. Not sure what happened there if it was user error or what. Also not sure if this is something that can be added or not, but the ability to input a lat/lon would be awesome!

LightningCast: LightningCast did a really great job today, especially V2 with the ABI+MRMS. We observed that this version detected lightning much earlier over eastern Pennsylvania compared to V1. Our storms were more low-topped with much less instability, and we saw LightningCast pick up on the probabilities very quickly even when there was hardly a radar echo. The biggest feedback from today’s session was a lack of GLM data appearing in the Super Dashboard even though GLM data was directly over our DSS event in AWIPS. Lena explained that there are different GLM sources, and since my group was using density, that’s why it wasn’t showing up in the dashboard (at least I think that was the reason?) Regardless, we shared the feedback that it would be nice if those things matched to prevent confusion for the forecaster. On the plus side – I learned even more about GLM today!

OCTANE– Since we were in an area with lower instability, Jason recommended viewing CONUS OCTANE Speed as shear was good in the area. I was amazed at how well this product highlighted the convection. At a quiet point, we jumped down to Texas to observe the firing supercells in the SW, and noticed OCTANE had cooling cloud tops around 5 minutes before lightning cast picked up on it, so that was also an interesting observation. I continue to really, really enjoy using the CTC product with LightningCast overlaid. I would integrate this today into my normal every day DSS procedures in AWIPS if I could.

Figure 1: OCTANE CONUS Speed over WFO RLX

SZA played a huge role today, too, in helping me see the clouds at a higher brightness for a longer time than I normally would! The images below are just down right impressive. I don’t know any forecaster who wouldn’t want more time to have better visualization on satellite.

Figure 2: Pictured left: OCTANE Meso (no SZA), pictured right: OCTANE CONUS (with SZA) at the same time of 22:37Z

I had a harder time using GXI imagery today given all of the cloud cover already in place at the start of ops. It was difficult to make out areas of moisture on the 0.91. However I was still able to pick up on better areas of moisture with the 5.15

Figure 3: GXI imagery at 18Z focusing over WFO RLX

Just to add: Graphic created today for DSSm posted in Slack.

-simoom

Tags: None

OCTANE Mesoscale vs CONUS Speed

In a more contaminated sky, it appears the mesoscale speed product handled low level flow better when compared to the CONUS Speed. In the CONUS direction, it showed more of an easterly cloud movement; that movement could imply the 5 minute data was getting more of an influence from a thin cirrus layer.

Figure 1: OCTANE CONUS Speed product (colder anvil tops were filtered out with the white scale)

Figure 2: OCTANE  Mesoscale  Speed image valid from the same time as Figure 1. This shows the more accurate low level flow.

-wxboi

Tags: None

Cloud Top Cooling Signals

The Octane Cloud Top Cooling product provided a strong indication of the continued southwestward development of storms in advance. While in the towering cumulus stage of development, the CTC indicated the stronger updrafts. Later on, those towering cumulus continued to develop into mature thunderstorms. While highlighting the areas that ended up growing, I didn’t notice it flagging any of the bubbling cumulus in areas where storms did not develop. This raises my confidence in the product as being able to use it to identify areas of greater concern. It may be worth noting that high level cirrus hid any potential updraft development in the southern portions of the area. However, in this specific case that proved to be non-consequential

Figure 1: OCTANE CONUS cloud top cooling at 18:51 zulu. Cloud top cooling can be seen on the line extending SW from the then dominant supercell.

Figure 2: Radar screenshot from roughly the same time as Figure 1.

Figure 3: The OCTANE CONUS cloud top cooling at 1911 zulu. Showering more development and continued signals on the SW flank.

Figure 4: Radar corresponding with Figure 3. Storms continued to develop and intensify in the same region highlighted 20 minutes prior in Figure 1.

-wxboi

Tags: None

Big Ol’ Storms, Amazing Satellite Products!

Today’s focus for my group was over WFO FWD where discrete supercells developed, eventually congealing into a more linear storm mode. Being on the DSS desk today, I primarily used lightning products today, though I did peep at a few others. I wanted to take a moment to highlight the GeoXO 5.15/0.91 products for very clearly defining a moisture gradient over northeast TX that would eventually go on to be our focus point for CI.

Figure 1: WV/WVT/Itob/VISob Compare highlighting distinct moist/dry boundary

LightingCast:

Provided DSS using LightningCast V2 overlaid with OCTANE CONUS CTC. I really like using the products together as the increasing LightningCast probs nudge me to either contact or not contact an EM. Overall, I thought the product did very well. I did notice something odd in the dashboard that I spoke with the developer about – instances of GLM flashes were observed at a time there was a downward trend with LightningCast. Figure attached below.

Figure 2: LightningCast V2 vs V1

For documentation, here was the primary procedure I used today to make decisions:

Figure 3: OCTANE CONUS CTC w/ LightningCast (yellow circle is 8-mile radius DSS event)

Using all of the above mentioned products, here was a CWA graphic I put together:

Figure 4: DSS graphic

Feedback for Day 2

LightningCast: For the Dashboard, I feel like V2 did a better job than V1. The amount of variables being measured is a little confusing, and over time, I noticed I was more just looking at a trend rather than all of the different variables.

Stoplight: Though I never got to give the all clear for my DSS event, Stoplight matched up very well with LightningCast and radar trends.

OCTANE: Made some progress in terms of understanding some of the OCTANE products today, thank you for answering all of my questions, Jason! I really liked that we had 2 live weather events to compare the difference in the wind profiles with OCTANE. Yesterday, we observed a lot of greenish hues, indicative of stronger low-level flow. That element was a bit more lacking in FWD today, and the imagery corroborated that with more blue hues. Jason also showed us examples of cloud top divergence, with more blue/green colors indicating deceleration. After getting to know these products a little better today, I feel less overwhelmed by it.

GeoXO: I continue to be very impressed with this product’s moisture and boundary detection. The example I shared above was very impressive and mostly lined up with the 00Z HRRR.

SZA: Did not look at SZA today

-simoom

Tags: None

Satellite, Satellite, Satellite

Warm Sector and no Synoptic Forcing: Paducah Kentucky Edition

We started today with a very established capped warm sector. Dewpoints were in the upper 60s and low 70s across the CWA. MUCAPE values were in the 2000 to 3000 J/kg range with 0-1 km SRH around 250 m^2/s^2. The thermodynamic parameters had started off well, but an early afternoon filled with cumulus clouds may spoil the convective threat. None of the warm sector convection never had gotten a chance to get started, there were glimpses of potential, but would quickly fizzle out. This will change quickly into the evening as the cold front moves across the region, but it is out of the “operational period”.

Vertical Wind Profiles:

With much quieter weather this afternoon than anticipated, we were able to deep dive the various uses of OCTANE. One of those is looking at the vertical wind profile. At the 0-3 km layer there is consistent south-southwest motion, while the 3-6 km layer is moving west-southwest. This analysis allows us to create a sense of ground truth that we are able to compare with models.

Figure: Here in this image we have low clouds that are identified as this more brown color, while the higher clouds are in the green. In motion these clouds have a well defined hook vertical wind profile with the lower layers moving south-southwest and the higher layer moving west-southwest.

Figure: Here is the 22z RAP model hodegraph for the convection southeast of Marion in the previous figure. This paired with the satellite product listed above we are to say with good confidence that in Northwest Kentucky there is a well defined hooking hodograph.

Final Thoughts:

For a day filled with a firehouse of new techniques they all stood out with their uses. The common theme for me is confidence in the models and also the ground truth. Each of the techniques we were shown helped to build confidence in either direction. It will be interesting to see how effective these techniques are, when in a more normal “operations” setting filled with time and workload constraints.

-Blizzard

Tags: None

April 27th Severe Storms – A Satellite Analysis

A large-scale, multi-state severe weather event is unfolding across the Midwest and Ohio River Valley, extending down into the Mid-South region. With a broad warm sector and CIN dwindling, the first focus was to watch for any discrete cells out ahead of the front that would pose an all-hazards risk. To get an idea of where the best moisture is and where any gradients between dry/moist air exist, I utilized the 4-panel that shows modeled GeoXO data vs GOES-19 imagery. This imagery did a great job highlighting the areas of best moisture and showed a clear distinction in dry vs moist air.

Figure 1: 4-panel layout comparing GeoXO Synthetic data (top) vs GOES-19 obs (bottom)

For monitoring potential discrete CI in WFO PAH’s area today, we utilized the CONUS OCTANE Cloud Top Cooling product with LightningCast ABI+MRMS overlaid. As we watched the cap continue to erode through the afternoon, I noticed “popcorn” like cumulus developing that exhibited rapid vertical motion as detected by the OCTANE satellite imagery. Most of the activity that started to develop, though, quickly fizzled out due to the cold front being so far behind. Still, this was an interesting observation and a utility I find very useful for DSS operations. Outside of our area of interest, we got to watch how rapidly discrete cells developed south of Kansas City, and learned that there is a correlation being studied between how cool a cloud top gets and how instability exists in the environment.

Figure 2: Left Image: 18:32Z, Right Image: 19:22Z

We also learned today that we can analyze low-level winds with the OCTANE Speed/Direction sandwich. For the WFO PAH area, we observed more directional shear with low-level turning of winds. In this instance, I turned off the Speed layer and only had the Direction layer selected. This highlighted the area where low-level shear was greatest.

-simoom

Tags: None

Octane Warnings

For Day 4, we were DDC. The storm environment was favorable for tornadoes. Our group issued four tornado warnings. This was based on the Octane storm top divergence, ProbSevere, radar, and the near storm environment. Radar confirmed a supercell with a mid-level meso, but the beam was +10Kft above ground, so it wasn’t helpful for the low levels. We kept the tornado warning going based on the environment, and did add 2.5” hail to the warnings. This storm ended up producing 2-3” hail, and multiple tornadoes. The tornado reports were delayed.

The animated GIF above shows the tornado warnings (red polygons) along with MESH (top right) and no smooth cloud top divergence (bottom left) and high smooth cloud top divergence (bottom right). This was a strong supercell in a favorable environment for tornadoes, so warnings were issued despite the lack of reports or low level radar data.

In addition to issuing the first warning with about 30 min lead time for our forecast area, the Octane was also able to identify a cell that developed a couple hours later behind the main storm, and it showed it as sub-severe. At quick glance, these updrafts look similar on the Day/Cloud (see below), but Octane did not have strong divergence with that second cell, and MESH had only small hail. For that reason, we didn’t issue a second warning, which I think is a big feat. Sometimes not issuing can be just as important as issuing.

The image above shows two updraft cores on the Day Cloud Phase at 2124Z. These updrafts look similar but the Octane Divergence was able to differentiate and show that updraft 1 had less divergence than updraft 2. (See image below)

 

The image above shows Octane Cloud Top Divergence (no smooth left, high smooth right) at 2125Z, corresponding to the Day Cloud Phase image above. This product, in addition to MESH, gave confidence to hold off on a warning for that trailing storm to the west.

The animated GIF above shows the two updrafts mentioned above, along with the tornado warning (red box) toward the end of the event.  MESH is also shown in the top right, with a filter for values less than an inch. Storms are showing a weakening trend in the Cloud Top Divergence (bottom panels) and MESH (top right).

– Updraft

Tags: None