Daily Summary: Week 2, Day 3 (May 13, 2015)

In contrast to yesterday, today our forecasters received a warm welcome to South Texas, operating close together in Houston (HGX), San Antonio (EWX), San Angelo (SJT), and Midland (MAF). Forecasters were once again exposed to an blend of ongoing convection caused by a very large precipitation shield to the East and fairly consistent developing multi-cellular/linear convection in southwest Texas ahead of the dryline and inside a narrow corridor of instability. Today we saw extensive evaluation of the ENTLN lightning trend graphs, Lightning Jump, ProbSevere, and GOES-R CI and had a fair amount of coordination between teams of adjoining CWAs.

In an EWP first, each of the three teams issued a warning covering a single storm from three different CWAs. After a round of applause, forecasters were back at work.

Overall, an interesting day after a fairly pessimistic morning briefing. Here’s hoping for a strong finish tomorrow as we will most likely continue operations in West Texas.

-Darrel Kingfield, CMMS/NSSL Research Associate & Week 2 EWP Coordinator


Feedback from Daily Debrief
- Bill Line, SPC/HWT Satellite Liaison

GOES-R LAP.
- PW did well – represented the gradients closely. With spc meso, was within 10%.  Gradients and advection were represented well.
- Only bad thing is the striping, sharp, unrealistic gradients.
- Did a good job with axis of instability, convection developed along the gradient, where one would expect

NUCAPS
- I looked at a sounding (modified) ahead of the developing convection in Texas; it showed that the environment was quite unstable with adequate moisture. To the west, much less instability and little moisture in the profiles. Storms moving into the area of the first RAOB grew strong and produced severe, with no new development to the west.

GOES-R CI
- It did much better than the past few days, maybe cause there was less clouds around, keyed in on initial cu development. I was able to see a trend, increase in probs, then storms went in satellite. Would be helpful as a border cwa, to use data in mexico, to see where storm would go
- When we switched to midland, did well showed development along a line right away
- In South Dakota where instability was weaker, it did not do well. In florida where instability was abundant, it was doing better.
- Concern in San Antonio was if it any storms along the boundary would reach us, seeing CI pick it up told us that something would build south, and indeed move into our CWA
- In San Angelo, ci was keying before storms first formed, once it started, gave increased confidence that line would continue to grow. Was some cloud cover to start too

ProbSevere
- Storm went up to 89% scan or two before we issued warning. When warning was almost expiring, we were sure exactly what we wanted to do. Probsevere started to come down, plus not looking good on radar, used this to expire warning.
- I issued a severe thunderstorm warning based on just probsevere. Glaciation and updraft both strong. I placed polygon same time that probsevere reached its max. Seeing rapid increases in probs increased my confidence to issue severe warning. Three body spike soon after. I used only the base reflectivity and ProbSevere to issue the warning.
- Useful to have lower values to see ramp up in probs, blocking out low probs would cause us to miss some trends.
- A time trend graph in probs would be useful to see
- I liked using it with mrms underlay, times match

Lightning jump
- Negative LJ was a sign of rapid storm dissipation, before storm weakened. Perhaps there should be a color scale for the negative “jumps”.
- It did well at capturing upward trends, but easy to miss them with the 1-min updates.
- Sometimes chaotic with different values in LJ from scan to scan.

PGLM