MAF lightning jump

Reeves County supercell yielded useful lightning jumps on a few occasions.

Approximately 21:20Z jump of 2 sigma preceded severe hail reports.

A 21:45Z jump came ahead of pronounced inflow notch, right turn and tornadic behavior.  At this point fluctuations in the level continued to produce  some jumps that stood out, but the storm was already clearly severe.  Pictured is 22:32Z, along with path.

– Holaday

Storms Develop in MAF

Convection developed in MAF CWA. Convective initiation probability exceeded 50% approximately 30 minutes before storms developed over Jeff Davis County.

Range from MAF radar is a limiting factor for storm analysis in this part of Texas. Subject had awareness of this due to Radar Quality Index (shown here as overlay on visible satellite).

This underscores the utility of GOES-R based products to the forecaster.

Modest jump in lightning also observed, may be examined in another post.

CIMSSPWRET imagery

Additional convective development continues late this afternoon mainly along the sharp CAPE gradient in southwest Texas.

ENI LJDA Sigma Values Not Matching Time Trend Flash Data

The ENI time trend flash data for a storm in sern NM did not seem to indicate the 7 sigma jump in strikes seen in the  LJDA. The LJDA had a 7 sigma jump indicated at 2235Z, however the time trend trace does not seem to warrant that value.

Lightning Jump with Pulsing Storms

The Lightning Jump Detection Algorithm showed sigma values of 2 to 5 with some storms in the Western Portion of Norman’s CWA. Immediately after each jump there was a corresponding downward spike in lightning as seen in the Earth Networks time series below. This shows the pulsing nature of these storms.


The lightning detection color codes are helpful, but it would be nice to overlay these on radar to easily match up with cells. Perhaps make the shading translucent.

Convective Initiation across southern OUN CWA

Forecasters were originally split between the Midland and Lubbock TX CWAs, but as it became evident that convection would either not occur or be very limited in the Lubbock CWA, one group of forecasters were moved to the OUN CWA. A cold front sparked shower and thunderstorm development in Southern Oklahoma, and the GOES-R CI algorithm caught the overall initiation pretty well. Below is a loop from 19-22 UTC showing the evolution of the CI product as storms developed.

  Jewett

Pickles 5/18/2015 22z

The modified NUCAPS sounding showed very good correlation with latest RAP output. (Fig 1) The lowest level of the sounding was modified based on nearest obs from KMRF and KE38 to generate around 2700 J/KG of MUCAPE. (Fig 2) This correlated well with the latest RAP data. (Fig 3)

Fig1

Fig 2

Fig 3.

NUCAPS

A VIIRS Satellite Pass at 1944Z provided a NUCAPS Profile near some developing storms in Texas. It provided a nice snapshot of the atmosphere in between soundings. The surface temp and dewpoint were modified in the sounding below based on nearby obs. When evaluating these storms with the Prob Severe Model it showed MUCAPE values of around 3800 J/KG. Meanwhile the GOES R Sounder product indicated layer CAPE of around 2700 J/KG in this area. The NUCAP reinforced the higher values. It seems like it would be useful in identifying areas to watch for convective development or monitoring modification of the atmosphere (like a dissipating cap).

Although the lat/lon is shown in the NUCAPS sounding, it would also be useful to have the point plotted on a map within the sounding. For quicker review of nearby soundings it would be nice to just mouse from point to p

A Win For NUCAPS

The NUCAPS sounder represented the environment across Oklahoma this afternoon really well compared to the nearby surface observations. Below is a sounding from a mostly sunny region near some developing convection.

The near surface environment shows a temperature of 76 to 77 degrees and dewpoint of 67. The closest surface observation had a temperature of 80 with a dewpoint of 65. Pretty good.

CI Signal Consistency Hits Initiation

When monitoring boundary layer cumulus, some sporadic CI pixels over 50% would occasionally be seen. However, an area was seen to slowly increase in probability with each CI/Vis product evaluated over 60 minutes in southern Reeves county. A great contrast can be seen with CI data over southern Reeves county in srn TX /MAF forecast area/ vs the county to the south /Jeff Davis/. The southern county had inconsistent CI signal versus the northern signal in Reeves county, which initiated and did cause a warnable storm.