With the move to ICT we were able to issue our first warning of the project. The storm that was previously discussed re-intensified after splitting. The increasing reflectivity aloft led to the MEHS data to give a hail estimate of 1.55″ and pushed the ProbSevere up from 58% to 95%.

Thus, a warning was issued for that cell.

To the northwest, a storm in DDC started to take a right turn right around the same time as a series of 2-3 sigma lightning jump values (orange in bottom left screen). Those values occurred as the storm intensified on radar and led to the ProbSevere values rising from 80% to 97% as it was nearing the cwa. Also, notice the overshooting top detection in the lower right screen.

With all of those values and the expected movement into the cwa, issued a warning for the ICT area for the storm.

-SRF

Looking back at the big picture and focusing on the GOES-R convective initiation, there was not much showing in our area of responsibility (TOP) but further south in northern Oklahoma I noticed some increasing probabilities at 1900 UTC.

15 minutes later at 1915 UTC the CI probability jumped to 90% on the east side of a cluster of identified clouds while there were also 40% probs on the west side.

Immediately after this time it was evident there was convective development was occurring as seen in this 2000 UTC satellite image below.

By 2030 UTC some CG lightning strikes were noted seen in the image below.  Radar at 2030 UTC also included.

Jack Bauer

With limited convection in the OAX area, we have moved over to ICT. The ICT CWA is along the same boundary, but now is on the southern side.

Taking at the quick look at the radar, there is a strong thunderstorm over the north-western part of the CWA. I decided to use the ProbSevere data as a quick overview and found the MRMS MESH data (hail size ~1″) to be very helpful in giving a quick look at the current expectations on the storm. I also found the satellite indicators to be helpful with the switch to indicate the current state of the storm (Mature).

Starting to see some increase in the eastern cell while typing this and will follow up this blog post with additional information. -SRF

CI was 81 at 1830z in northern Jeff Davis County (first image). By 1901z 0.5 deg reflectivity (image 2) showed the first greater than 35 dBZ returns. By 1945z the Probability of Severe was 27 percent (image 3). Severe hail, 1.75 inches, was reported at 2008z through 2025z (image 4). By 2049z the storm had a massive Three-Body Scatter spike (image 5).

Time from the 81 percent chance of CI to hail report was 98 minutes.

Time from the first 35 dBZ returns to hail report was 67 minutes.

Time from 27 percent Probability of Severe to hail report was 23 minutes.

-Lynford

Last three images from Vivian Darkbloom

I like the gradual color change and polygon thickness increase as the probabilities increase. See the image below for an example of the lower prob (thin blue) vs the higher prob (thick pink) and some gradients in between. This allows a warning forecaster the opportunity to quickly filter the sub-severe storms and focus on the potential for stronger convection in other areas.

Brick Tamland

Noticed how a storm may briefly increase to 40 flashes/min, yielding a level 3 DTA for a cell. See the images below which highlight that although the DTA threshold was met for briefly for a few minutes, the successive flash rates dropped below the 40 flash/min threshold for minutes thereafter. The DTAs may be more useful for operational forecasters if the valid time were reduced from 45 mins to 30 mins. This would reduce the amount of products that may clutter up the radar interrogation process.

Brick Tamland

Now that we have a verified severe storm in Midland’s area, let’s see how the lightning jump and probability severe algorithm worked.

At 1945Z, the algorithm showed a severe probability of 27%. The lightning jump was nothing to jump about.

With the next 0.5 deg scan at 1950Z, the probability skyrocketed to 83%.

At 2031Z, a 3 sigma lightning jump occurred. Severe probability was 93% at this time.

By 2049Z, the cell grew into this beast. Max reflectivity on the 0.5 deg tilt was 75.5 dBZ @ 16000 ft MSL/12230 ft AGL. A prominent TBSS had developed on the storm by 2040Z.

The LSR associated with this storm is shown here. Severe hail was observed beginning at 308 PM CDT/2008 GMT. In this case, the lightning jump occurred over 20 minutes after the storm began to produce severe hail. However, the probability severe did provide a lead time of about 20 minutes.

-V. Darkbloom

Below is an image where the western cell was in the western US section of the thunderstorm alert area and the eastern cell was in the eastern US section of the thunderstorm alert area. Both sections are in the Midland CWA. Note the long lift of products loaded to have both cells in a Level 1 thunderstorm alert. Why was there no Level 2 alert on the eastern cell? It had 12 or more flashes for 2 to 3 minutes.

This set up with a set boundary will be cumbersome when it crosses through any CWA.

-Lynford