We didn’t have too many storms occur during operations today, but that allowed us to be able to focus more on CI.
Category: GLM
ILN HWT Blog Day 3
NUCAPS
GLM & LightningCast
PHS
ProbSevere
GLM maxFED Comparisons
NUCAPS Sounding (IND 06/08/2022 2019 UTC)
Lowering maxFED values effectively highlights the area of strongest thunderstorm activity as seen in this example. This makes the strongest two thunderstorms (circled) more distinguishable from other thunderstorms, especially on the northern circled thunderstorm. It should be noted that this may be even more effective during the initiation to nearing maturity stages. Once a storm reaches full maturity, FED signal may be much higher.
– 2%hatched
Two Storms GOES 16 v 17
Being on the western edge in the North Platte County Warning area we did a comparison versus GOES 16 and 17 with the GLM Flash Extent Density. At first there wasn’t much of a difference, but when storms started to ramp up more and we had a decent eastern and western storm there was a difference.
As you can see our eastern storm shows up better on GOES 16 and not as good on GOES 17. Meanwhile the western storm there is a much greater difference in the Flash Extent Density (and Total Optical Energy) on GOES 17. This matches with what was stated at the initial discussion this morning that GOES 17 may work better with western storms.
-Noctilucent
Northeast Colorado Supercells
Nowcasting Supercell storm entering CWA: The loop of instability and SigTor highlight the southeast/south central CWA east of Colorado Spring, ahead of an already ongoing storm. North of this storm an environment of favorable instability exists up to about the latitude of Denver, with a significant drop off to the north.
When it comes to high and northern plains – parallax becomes an issue. In this case lighting was occurring just on the other side of the border with the CWA, so here are the two LightningCasts (with/without parallax correction) for comparison:
ProbSevere v3 increases correlating to entering a favorable environment
PHI localized CAPE corridor
New area of MFA suggesting spitting storm with new updraft core of the established cell. (1950 UTC)
Storm cell split denoted by MFA with two distinct areas of MFA in upper right panel. (2000 UTC)
Focused on the cell east of Denver – this cell and subsequent others that developed are in the favorable area of instability. Just to the north of Boulder we spotted a few cells that attempted to develop, however in the lower instability environment movement off the higher terrain resulted in these cells falling apart. Through the rest of the afternoon this area remained convection free.
Sig Tor blip. A SRVE like feature was observed but at this time convergence associated with this feature wasn’t favorably located under the updraft.
Cell developing east of Denver, noted by the MFA in the upper right panel. (2020 UTC)
Cell rapidly develops in an area of localized higher instability denoted by the PHS values discussed earlier on.(2034 UTC)
The LightningCast has identified the left turning nature of the storm(s) east of Denver
An interesting note was comparing the differences between GOES East (left panel) and GOES West (right panel). These subtle differences can be effective in analyzing the strengthening of a thunderstorm.
In the middle of METWATCH – NUCAPS became available (about 1 hour latency). The sounding below is a modified NUCAPS profile, depicting the environment in which our storms developed. Storm mode was supercellular with frequent spitting of cells.
-Mr. Bean
-2%hatched
CYS HWT BLOG Day 2
LightningCast for storm approaching Scottsbluff
GraphiCasts with ProbSevere and PHS
GLM – GOES-16 vs GOES-17
Differences between the GLM Flash Extent Density products from GOES-16 and GOES-17 were quite stark for convection occurring over the Cheyenne, WY CWA on June 7th.
The two animated gifs below highlight the difference in lead times for an observed uptick in lightning activity within a cell near Scottsbluff, NE. The first animation is of GOES-17 showing the uptick in lightning activity beginning at 1939Z. The second animation from GOES-16 shows the same uptick in lightning activity, except beginning ~5mins later at 1945Z. Interestingly enough, both satellite perspectives show the downtrend in lightning activity occurring at 1950Z.
GOES-17 GLM FED Scottsbluff 5-min improved lead time.
GOES-16 GLM FED Scottsbluff
The next three examples show sharp contrasting GLM FED intensities between GOES-17 and GOES-16 through the afternoon of June 7th. This first example focuses on a warned supercell just southeast of Scottsbluff, NE at 2022Z. The first image shows FED from GOES-17 showing much higher FED numbers, while the second image shows FED from GOES-16 not indicating any increased lightning activity. The third image shows a 4-panel layout of MRMS, MESH, VIL, and ProbSevere version 3 all supporting a supercell occurring. A subsequent report of 1.5” hail was observed from this warned storm.
The cause of this was shared from the investigators running the HWT this week, that GOES-17 had the better angle to see lightning activity in these supercells developing over the high plains of WY and NE. Whereas GOES-16’s perspective from further east had to punch through spreading anvils downstream of the main updraft that likely obscured the light emanating from the lightning, GOES-17 had a more side-on view of the updraft with less to no obscurations of light emanating from lightning occurring in the updraft. Unfortunately, GOES-17 CONUS view and the day’s mesosector from GOES-17 did not reach this far east and there are no satellite images displaying the different parallax views from GOES-16 and GOES-17.
GOES 17 GLM FED @ 2022Z “Scottsbluff Cell”
GOES 16 GLM FED @ 2022Z
MRMS – MESH – VIL – PROBSEVEREv3 @ 2022Z
1.5” hail report from this storm. Max MESH reached 2”.
The next two examples below each showcase three images each, a GOES-17 FED showing higher intensity lightning activity, a GOES-16 FED missing the higher intensity lightning activity, and a 4-panel layout showing MRMS, MESH, VIL, and ProbSevere version 3 highlighting the severe nature of the supercell.
An interesting follow-up to this in the future is to see how these two satellite GLM FED products compare in a low-storm motion environment where the spreading anvils at storm top flow in all directions. This could cause both satellites to have an obscured view of the convective updraft beneath, causing both to miss out on any increased lightning activity.
GOES-17 GLM FED @ 2016Z “Lance Creek Cell”
GOES-16 GLM FED @ 2016Z “Lance Creek Cell”
MRMS – MESH – VIL – PROBSEVEREv3 @ 2016Z
GOES-17 GLM FED @ 2026Z “Scottsbluff Cell”
GOES-16 GLM FED @ 2026Z “Scottsbluff Cell”
MRMS – MESH – VIL – PROBSEVEREv3 @ 2026Z “Scottsbluff Cell”
– Trip
ProbSevere v3 and NUCAPS
When analyzing a thunderstorm developing over western South Dakota, a noticeable jump occurs near 20:25 – 20:30 UTC as seen on the ProbSevere Time Series. At this same time, there was a distinct uptick in lightning activity seen in the GLM 4 panel. This would correlate with a strengthening of the thunderstorm at this time. A modified NUCAPS sounding from around this time captured an environment favorable for further strengthening encompassed by steep mid level lapse rates and adequate instability. This thunderstorm was beginning to exhibit severe hail potential.
ProbSevere Time Series
GLM-16 4 panel
Modified NUCAPs sounding ~20 UTC
-2%hatched
LBF Day 1 HWT Blog
Day 1
PHS, ProbSevere
LightningCast
GLM and Minimum Flash Area
Lightning energy during the HWT was introduced in several different ways. Three of these were:
- Flash Extent Density
- Minimum Flash Area
- Total Optical Energy
For monitoring severe thunderstorms, Flash Extent Density seemed to be the most useful of the three.
However, all of the GLM products were what we focused on.
In order to obtain GLM lightning data on the grid or map, you had to obtain a Minimum Flash Area. It was interesting in the stratiform type storms that a wide area was displayed compared to the small area where the flash took place. In this case it was one cloud-to-ground lightning strike (CG).
This image is from the Bottom-Right panel (CG and Cloud Flashes):
This is the top-right panel (Minimum Flash Area):
This shows that one CG Flash can plot a large area on the Minimum Flash Area product. It seemed that this was necessary for other products to plot, such as the Flash Extent Density, but it may be a little bit of a distraction for the operational forecaster as it would seem to flash a bit (on and off if looping it) and for a much larger area than what was shown compared to the cloud Flash and CG plots.
– WeatherTed