ALEXANDERS DARK BAND/LYNFORD
Thursday, May 7, 2015
GOES CI in Amarillo CWA
Morning MCS over the southeastern Texas panhandle has resulted in a north-westward propagating outflow boundary. This boundary has merged with a loosely defined dryline in northern parts of the CWA, with the dryline then extending further to the south. More elevated values of GOES CI (30-60%) has focused very well along these boundaries. An area of 75% probability was indicated at 1937 UTC. By 1956, a weak echo was apparent in the AMA radar reflectivity. By 2008 UTC, the intensity had increased to 50-60 dBz.
ALEXANDERS DARK BAND/LYNFORD
ALEXANDERS DARK BAND/LYNFORD
LBB Prob Severe and Lightning Jump
Looking at prob severe and the lightning jump associated with a particularly nasty looking storm.
The prob severe at 1918Z – 52%
1924Z – prob severe jumps to 70%
1926Z prob svr – up to 85% with a 3 sigma lightning jump
1927Z – 65 dBZ at almost 27 kft AGL!
A severe thunderstorm warning was issued at 1932Z. No reports yet.
-V. Darkbloom
1924Z – prob severe jumps to 70%
1926Z prob svr – up to 85% with a 3 sigma lightning jump
1927Z – 65 dBZ at almost 27 kft AGL!
A severe thunderstorm warning was issued at 1932Z. No reports yet.
-V. Darkbloom
Storms Firing Along Outflow Boundary in Southern OUN CWA
Strong thunderstorms are developing over northwestern TX along an outflow boundary left over from convection over OK and northern TX. The ProbSevere values increased between 1902 and 1916 UTC (Figure 1).
The Norman forecasters have noted the uptick in the ProbSevere data with these storms. The ProbSevere data combined with analysis of base radar data and knowledge of the storm environment was used to issue experimental severe thunderstorm warnings at 1921 UTC (northern warning) and 1924 UTC (southern warning) (Figure 2). The ProbSevere probabilities first exceeded 50% for storms A-D in Figure 1 at 1904 UTC, 1926 UTC, 1910 UTC, and 1914 UTC, respectively.
-Sieglaff
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| Figue 1. NOAA/CIMSS ProbSevere Model, composite radar reflectivity and GOES-EAST visible imagery valid 1916 UTC 07 May 2015. |
The Norman forecasters have noted the uptick in the ProbSevere data with these storms. The ProbSevere data combined with analysis of base radar data and knowledge of the storm environment was used to issue experimental severe thunderstorm warnings at 1921 UTC (northern warning) and 1924 UTC (southern warning) (Figure 2). The ProbSevere probabilities first exceeded 50% for storms A-D in Figure 1 at 1904 UTC, 1926 UTC, 1910 UTC, and 1914 UTC, respectively.
 |
| Figure 2. NOAA/CIMSS ProbSevere and KDYX 0.5 degree reflectivity valid at 1926 UTC 07 May 2015 |
-Sieglaff
Warning issued for Storms over SW OUN CWA
Rapidly intensifying storms entering the OUN cwa where picked up well on ProbSevere, with them quickly rising to 90%. Based of the reflectivity cores aloft, broad rotation, and the rapid increase in ProbSevere, have issued warnings for multiple storms in the SW corner of the cwa (at 1922 and 1924Z).
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Will be monitoring the lightning trends and see if the data catches up with the radar and ProbSevere appearance.
-SRF
Comparison of ProbSevere and Custom DTA
After setting up the custom Thunderstorm Alerts (75/min and 100/min), there were a couple areas of focus on the 100/min alerts (to the west-southwest and southwest of KTLX).
But when comparing to the ProbSevere data, we are seeing different representations on the strength of the storms. The storm to the WSW only had a ProbSevere around 11% (that had the greatest flash rate around 149 per min), while the storm to the SW had a ProbSevere of 88%, but a weaker flash rate (87 per min).
These differences highlights the need for analyzing multiple data sources and comparing to radar.
-SRF
But when comparing to the ProbSevere data, we are seeing different representations on the strength of the storms. The storm to the WSW only had a ProbSevere around 11% (that had the greatest flash rate around 149 per min), while the storm to the SW had a ProbSevere of 88%, but a weaker flash rate (87 per min).
These differences highlights the need for analyzing multiple data sources and comparing to radar.
-SRF
Lubbock Today – Initial Look
This morning iin the TX panhandle there was an existing west-east line of thunderstorms stretched across the northern portion of the LBB CWA. A warm front was aligned SW-NE across the AMA CWA, with a dryline across the southern panhandle and a nice dryline bulge south of the CWA.
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GOES-R PW
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GOES-R CAPE
CI has tended to be more of a “now”cast as opposed to a forecast.
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CI at 1815Z
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Radar at 1814Z
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Radar at 1824Z
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CI at 1825Z
By the time the CI was high, convection was already ongoing in that area. More frequent satellite data would definitely help in these rapid development situations!
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GOES-R PW
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GOES-R CAPE
CI has tended to be more of a “now”cast as opposed to a forecast.
.png)
CI at 1815Z
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Radar at 1814Z
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Radar at 1824Z
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CI at 1825Z
By the time the CI was high, convection was already ongoing in that area. More frequent satellite data would definitely help in these rapid development situations!
CI ahead of shower development
CI from 1825z (image 1) showed an 83% probability of development. Showers first reached 35+ dBz at 1843Z, 18 minutes later over Texas County, OK (image 2).
Lynford
Lynford
Week 1 Final Day
The forecast crews are setup in Norman, Lubbock, Amarillo WFOs today for the final day of the week 1 EWP operations (Tales from the Testbed will occur on Friday).
The Norman crew has a lot of ongoing convection in the southwestern portion of the CWA. While they were getting acquainted with the setup and datasets for the day one forecaster noticed a rapid jump in the NOAA/CIMSS ProbSevere output on a cell ahead of the bulk of the ongoing convection, the forecaster's blog post is shared below:
Rapid Increase in ProbSevere:
While we were writing up a previous blog post, we noticed rapid increase in the ProbSevere for a storm to the west of the OUN radar. The ProbSevere quickly ramped up from 9% to 94% as seen in the two images below.
Figure 1: NOAA/CIMSS ProbSevere and KTLX 0.5 degree reflectivity valid at 1828 UTC 07 May 2015.
Figure 2. NOAA/CIMSS ProbSevere and KTLX 0.5 degree reflectivity valid at 1832 UTC 07 May 2015.
Seeing that rapid increase was noticeable to both of us as were were typing up other blog posts and prompted us the interrogate the radar data. While the core looked small initially, the idea shown by the ProbSevere was right on.
Finally, with the location of the cell being right under the clouds from upstream convection (see image below), it led to N/A values on the satellite data.
-SRF
Initial Analysis localized as OUN
Water vapor imagery early this afternoon is showing a deep closed upper low over CA with broad southwesterly flow across the southern plains with a weak disturbance moving through the flow which seems to be enhancing/sustaining convection moving through the western portion of the forecast area. Visible imagery shows well the ongoing convection as well as a boundary situated across KS southwestward into the OK/TX panhandle.
A quick look at the GOES-R CAPE showed values generally in the 1000-1500 J/kg except along the Red River where lower values were shown below 1000 J/kg. There definitely appears to be some influence of cirrus and mid level clouds associated with the ongoing convection affecting the output.
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Comparing the GOES-R CAPE to the SPC mesoanalysis mixed layer CAPE it appears the values are too low, especially in the Red River area where values close to 2000 J/kg were noted.
The continued moist southeasterly flow into the region today south of the ongoing convection should interact with outflow boundary from ongoing convection and initiate new convection across the southern portion of the forecast area.
Jack Bauer
A quick look at the GOES-R CAPE showed values generally in the 1000-1500 J/kg except along the Red River where lower values were shown below 1000 J/kg. There definitely appears to be some influence of cirrus and mid level clouds associated with the ongoing convection affecting the output.
.png)
Comparing the GOES-R CAPE to the SPC mesoanalysis mixed layer CAPE it appears the values are too low, especially in the Red River area where values close to 2000 J/kg were noted.
The continued moist southeasterly flow into the region today south of the ongoing convection should interact with outflow boundary from ongoing convection and initiate new convection across the southern portion of the forecast area.
Jack Bauer
Rapid Increase in ProbSevere
While we were writing up a previous blog post, we noticed rapid increase in the ProbSevere for a storm to the west of the OUN radar. The ProbSevere quickly ramped up from 9% to 94% as seen in the two images below.
Seeing that rapid increase was noticeable to both of us as were were typing up other blog posts and prompted us the interrogate the radar data. While the core looked small initially, the idea shown by the ProbSevere was right on.
Finally, with the location of the cell being right under the clouds from upstream convection (see image below), it led to N/A values on the satellite data.
20150507_1830Z_Sat_Radar-SRF
Seeing that rapid increase was noticeable to both of us as were were typing up other blog posts and prompted us the interrogate the radar data. While the core looked small initially, the idea shown by the ProbSevere was right on.
Finally, with the location of the cell being right under the clouds from upstream convection (see image below), it led to N/A values on the satellite data.
20150507_1830Z_Sat_Radar-SRF
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