Last night's focus area was in western KS, centering on the Dodge City and Goodland, KS CWAs with one team also monitoring activity in Lubbock, TX. Storms fired late in the afternoon and kept us fairly busy for the remainder of the night. Forecasters had a lot to say about the GOES-R products. Check out some of the feedback below:
Cloud Top Cooling:
- 'Cloud-top Cooling helped early before cirrus contamination.'
- 'Most storms that went on to product large hail had a strong CTC signal.'
- '[The CTC] provided good situational awareness, was a good quicklook and helped identify areas of interest.'
- 'It provided lead time of up to an hour for storms that produced large hail, especially wehre there was a persistent strong signal over through several satellite scans.'
- 'Seeing the consistently higher CTC signals in an operational environment would give me further confidence to warn on a particular cell.'
- 'A lot of time there were strong signals for the robust cores, though not always.'
GOES-R CI:
- 'The CI didn't help with individual elements; that is, it was noisy. There were a wide range of values in a small area. However, backing out and taking a broader view, it gave a general idea of where I could start to expect things to occur.'
- 'Even right before storms got going there weren't a lot of clustered 90% values, but there were a few here and there... so the trend was good.'
- 'The CI was noisy, especially within large cu fields. It may be helpful if it were thresholded a little bit, if only 50% or greater probability values were shown.'
Nearcasting:
- 'While waiting for stuff to get going, I really enjoyed the Precipitable Water difference. There was cu in an area of low-level moisture and as soon as they moved into an area of higher moisture, they fired.'
- 'It helped to know what was happening in the current atmosphere and what to expect later.'
- 'The development to the west was associated with marginal moisture, but just to the east there was a lot more, and as soon as those cu moved into that area it lit up like a Christmas tree.'
Simulated Imagery:
- 'The IR satellite forecast was a little early but really showed the individual storms from western KS south through Texas. It did also keep the are in KS a little longer, which did pan out.'
PGLM:
- 'It was a precursor to what happened... flash density increased to 30 flashes/min with one cell and five minutes late it produced large hail, the only hail report near Lubbock.'
Again, keep an eye on the blog. Today looks to be a busy day with the focus on Texas and Oklahoma. More details on this later in the afternoon...
Wednesday, May 8, 2013
Tuesday, May 7, 2013
Hail Lead Time from Cloud Top Cooling Products
As several storms developed in the DDC forecast area, and very slowly reached maturity (and severe intensity), the Cloud Top Cooling (CTC) product provided a significant amount of lead time.
At 2202Z, three areas showed strong (20+) indications on the CTC product. The two areas in Lane and Clark Counties went on to produce severe thunderstorms. However, the smaller area in Haskell County did not end up with severe hail reports. All three of these CTC areas continued for several consecutive time steps.
An hour and a half later, a new area of strong CTC developed in Ness County. This area also persisted for several time steps, and preceded severe thunderstorm development as the storm moved into Trego and Ellis Counties. The area near Haskell County was associated with the one storm that did not become severe, while the Clark County CTC area was associated with the severe storm moving out of Ford County.
With the exception of the sub-severe Haskell County storm, the other three CTC indications were associated with future severe hail reports.
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| CTC at 2202Z, showing strong indications in Lane, Clark, and Haskell Counties. |
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| CTC at 2232Z. A new area has developed in Ness County. |
An hour and a half later, a new area of strong CTC developed in Ness County. This area also persisted for several time steps, and preceded severe thunderstorm development as the storm moved into Trego and Ellis Counties. The area near Haskell County was associated with the one storm that did not become severe, while the Clark County CTC area was associated with the severe storm moving out of Ford County.
With the exception of the sub-severe Haskell County storm, the other three CTC indications were associated with future severe hail reports.
Hatzos
EWP2013 7 May 2330 UTC Mesoscale Discussion
We continue to monitor isolated to widely scattered supercells extending from NW KS through SW KS/NW OK, with more isolated activity near LUB.
Recent sfc obs show area of backed winds over NW KS on northeast fringe of a broad lee trough drifting eastward from CO. Here, pooling moisture has contributed to modest instability per recent mesoanalysis with impressive wind fields, albeit somewhat weak in the upper levels. Some meager low level rotation has resulted from this area of backed surface flow, with a few reports of weakly rotating wall clouds. As LCLs decrease this evening, a very narrow window for tornadic development will exist, but low level shear will continue to limit this threat.
Further south, large hail and damaging winds have been the main threats with a few reports of up to golf ball sized hail. Deeply mixed boundary layer has resulted in high based storms within impressive steep mid level lapse rates favorable for hail production. Also, with inverted V nature of area soundings, would not be surprised if very strong winds are occurring with the most severe storms.
Even further south, areas in and around Lubbock have seen very isolated storm development this evening. One single slow moving supercell has been located near the border of Garza and Crosby counties. This storm also developed in a very localized area of backed surface winds, with enhanced surface convergence. Also, surface heating likely played a role in convective initiation, with temperatures climbing into the mid to upper 80s. This development was preceded by multiple CI and CTC signals, though they tended to be sporadic and indicated there may be many more storms than actually developed.
Heading into the evening, expect severe storms will generally persist through around 02z to 03z. Most activity appears to be diurnally driven. On exception to this will be parts of NW/N Cntrl KS, where an eastward propagating cluster may develop later this evening. Taking a look at Nearcast products, we observe that instability has taken a bit of a hit over the entirety of the area with ongoing convection, as has moisture depth. It still appears the most favored areas for persistent severe convection and supercellular activity will be over NW KS in Goodland’s CWA, eventually migrating into Hasting Nebraska’s area of responsibility.
Lubbock’s convection has diminished in the last hour, and will discontinue operations there. Will keep operations at DDC and GLD active through end of day as activity is expected to continue.
Austin
Recent sfc obs show area of backed winds over NW KS on northeast fringe of a broad lee trough drifting eastward from CO. Here, pooling moisture has contributed to modest instability per recent mesoanalysis with impressive wind fields, albeit somewhat weak in the upper levels. Some meager low level rotation has resulted from this area of backed surface flow, with a few reports of weakly rotating wall clouds. As LCLs decrease this evening, a very narrow window for tornadic development will exist, but low level shear will continue to limit this threat.
Further south, large hail and damaging winds have been the main threats with a few reports of up to golf ball sized hail. Deeply mixed boundary layer has resulted in high based storms within impressive steep mid level lapse rates favorable for hail production. Also, with inverted V nature of area soundings, would not be surprised if very strong winds are occurring with the most severe storms.
Even further south, areas in and around Lubbock have seen very isolated storm development this evening. One single slow moving supercell has been located near the border of Garza and Crosby counties. This storm also developed in a very localized area of backed surface winds, with enhanced surface convergence. Also, surface heating likely played a role in convective initiation, with temperatures climbing into the mid to upper 80s. This development was preceded by multiple CI and CTC signals, though they tended to be sporadic and indicated there may be many more storms than actually developed.
Heading into the evening, expect severe storms will generally persist through around 02z to 03z. Most activity appears to be diurnally driven. On exception to this will be parts of NW/N Cntrl KS, where an eastward propagating cluster may develop later this evening. Taking a look at Nearcast products, we observe that instability has taken a bit of a hit over the entirety of the area with ongoing convection, as has moisture depth. It still appears the most favored areas for persistent severe convection and supercellular activity will be over NW KS in Goodland’s CWA, eventually migrating into Hasting Nebraska’s area of responsibility.
Lubbock’s convection has diminished in the last hour, and will discontinue operations there. Will keep operations at DDC and GLD active through end of day as activity is expected to continue.
Austin
Possible Impacts to CTC from Cloud Ice in Anvil Cirrus Shield
The use of CTC was restricted quickly across the GLD CWA this evening as the cirrus shield from the first updraft quickly contaminated the region due to cloud ice. From this point on, the MRMS products became the primary aids in deducing severe hail development.
Note the lack of CTC within the GLD CWA, while new updrafts continue to be detected by the CTC across the northern portion of the DDC CWA.
Kurtz/Guseman
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| VIS imagery, CTC, IR, and MRMS QC composite reflectivity |
Note the lack of CTC within the GLD CWA, while new updrafts continue to be detected by the CTC across the northern portion of the DDC CWA.
Kurtz/Guseman
EWP2013 7 May 2013 2215 UTC Mesoscale Discussion
With multiple scans of CI/CTC showing iminent or ongoing convective initiation over Lubbock’s area, will localized one desk at the LUB wfo. This will give the testbed an opportunity to evaluate some of the PGLM products available in the LUB LMA. The image below from 2145 UTC shows where storms are developing in extreme south central parts of the CWA.
Radar trends show activity is also on the uptick at DDC, with ongoing supercells over GLD’s area. Will keep two teams stationed at these locations to optimize this marginal severe weather setup. The image below is a four panel of MESH products and composite reflectivity over the DDC and GLD CWAs.
Will continue to monitor trends, but all areas appear to be covered at this time.
Austin
Austin
Cloud Top Cooling rate Combined with MESH for Enhanced Lead Times
We continued to monitor Cloud Top Cooling (CTC) rates in combination with MESH from the MRMS to investigate a elevated storm in Sheridan County Kansas. CTC was able to provide 15 to 20 minutes of lead time before the MESH indicated .71 inch hail. Below is a four panel at 2115z of the CTC, instantaneous MESH, base reflectivity at KGLD, and 120 min MESH.
Continuing to monitor the storm, the HSDA has continued to indicate large (LH) to giant (GH) hail. With modest mid-level lapse rates (7.0-8.5 C/km) and decent mid-level shear, these storms continue to indicated mid and upper level rotation, indicative of large hail growth.
Guseman/Kurtz
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| Four Panel: CTC, MESH, 0.5 refl. KGLD, 120min MESH |
Guseman/Kurtz
EWP2013 7 May 2150 UTC Mesoscale Discussion
As was anticipated, isolated to scattered thunderstorms developed over northern and western portions of KS. This area will continue to be monitored for additional storm development, and intensification of ongoing convection as backed low level flow continues in this region. The image below shows composite reflectivity, MRMS mid level rotation tracks and MESH, reflectivity at -20 C and the HHC. This cluster of storms is gradually intensifying, and MESH has indicated the presence of severe hail.
We are still monitoring CWAs further south, LUB in particular, for convective initiation in the next couple of hours. A large CU field has developed in the last hour and is showing some CI and CTC signals.
However, this activity has been slow to develop, and severe convection does not appear imminent.
We are still monitoring CWAs further south, LUB in particular, for convective initiation in the next couple of hours. A large CU field has developed in the last hour and is showing some CI and CTC signals.
Nearcasting Shows Updrafts Reaching Moisture
The updrafts have reached the airmass with higher low-level moisture as evident by the darker pink/purple colors in the GOES PW Difference product. The updrafts have become better organized with a marginally severe storm currently in Western Kansas.
Hampshire
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| Left panel is Composite Reflectivity from MRMS and the upper right is GOES PW Difference. |
Hampshire
EWP Activity 5/7/13
After a relatively quiet start to the afternoon we've finally begun to see some activity. Currently we've got several of our forecasters keeping an eye on Dodge City, KS with the others on Goodland, KS where a number of cumulus clouds have been trying to develop for most of the day. The GOES-R CI hasn't been consistently showing higher strength of signal values thus far, though the Nearcasting (precipitable water difference) did indicate some moisture that may allow for further growth. One cell has already developed and been warned on by our forecasters. We'll continue to monitor this area for further convective initiation...
Following GOES-R CI
I had the chance to follow-up with forecaster Hatzos on the use of the GOES-R CI from a couple posts earlier. The operations were watching the Goodland and Dodge City, Kansas county warning areas as we continued to wait for storms to possibly fire up in eastern Colorado / western Kansas. We had the chance to discuss how the GOES-R CI product was performing given the current environment.
The image above is from 2015 UTC shows the GOES-R CI (upper left), IR imagery (upper right), and the Dodge City reflectivity (lower right). Looking at the previous observations, the GOES-R CI has done a good job of identifying the small cells developing in western Kansas, as shown in the radar imagery.
The image above is now from 2030 UTC and continues to show GOES-R CI identifying initiation with moderate values. I posed the question of what is the impression of these observations. Overall, the GOES-R CI has done well identifying initiation. In addition, the GOES-R CI values have been modest. During the conversation, this gave the forecaster the opinion that explosive development is not to be expected just yet and that given the current conditions, the operations will focus on monitoring storm development.
- Geoffrey
The image above is from 2015 UTC shows the GOES-R CI (upper left), IR imagery (upper right), and the Dodge City reflectivity (lower right). Looking at the previous observations, the GOES-R CI has done a good job of identifying the small cells developing in western Kansas, as shown in the radar imagery.
The image above is now from 2030 UTC and continues to show GOES-R CI identifying initiation with moderate values. I posed the question of what is the impression of these observations. Overall, the GOES-R CI has done well identifying initiation. In addition, the GOES-R CI values have been modest. During the conversation, this gave the forecaster the opinion that explosive development is not to be expected just yet and that given the current conditions, the operations will focus on monitoring storm development.
- Geoffrey
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