Two boundaries were evident over southern TX that had direct effects on the cumulus field, suppressing it, as it passed through. No evidence of a wind shift occurred with these boundaries.

The north-south boundary began in west TX earlier in the day and continued to move east. The W-E boundary is believed to be an old outflow boundary shifting south.

Rocky

Typical pulse convection seen in Harris county in southeast TX.  As these storms pulse and fall, the lightning jump algorithm has fairly consistently shown a corresponding jump around 6 sigma, down to 4, and then to zero as the storms collapse.

The good: The initial storms of the day in the Midland, TX forecast area formed in the Nearcast model most unstable differential thetaE depicted in the 0-1hr forecast (see the Nearcast+Radar+Visible image below).

The bad: Because my forecast area (San Angelo, TX) further east had prolonged morning clouds (see 14Z Visible image), the retrievals could not be accomplished and the instability trends in the Nearcast model through 9 hr were not available.

Rocky

LAPS PW and Stability all did a good job depicting the moist unstable air in the sou6thern and eastern portion of MAF CWA. The area enclosed in the white line represents initial convective initiation. As has been the case the past two days the north-south oriented line is along a zone of tight gradient of PW (and CAPE and other stability parameters).

In this case the PW field also shows more discreet areas of higher PW where convection is initiating in an east-west band in an area of clearing skies ahead of the surface cold front.

Overall, I think LAPS has done a very good job in providing an initial view of environmental conditions (and gradients) during initial severe weather analysis and spin-up. It helps focus in on areas most likely to see initial convective development, which can be verified against numerical guidance.

-snowstrm

Brewster Co TX cell was first of the shift in the MAF CWA.  Creating this to compare to the evolution of other cells in this environment as the afternoon goes on.

1730Z – CI  value at 73%, clearly the only object of immediate interest in the region at that time

1812Z – Prob Severe first passes 50% (jumped to 63%) with strong growth and moderate glaciation
1818Z – STA
1815-1822Z – first significant jump in ENI TFR (image below)
1822Z – Prob Severe reaches 90%

1838-1845Z – another significant jump in ENI TFR
1838Z – MRMS MESH first indicates sustained 1″ hail potential
1840Z – DTA
1842Z – MRMS MESH first indicates 2″ hail
1844Z – cell split becomes evident

-Holaday

Prob severe spiked up to 73% for the warned storm (top photo).  This also corresponded with a dramatic PGLM flash density increase to over 60 (bottom photo).

Using the PGLM, ProbSevere and KHGX all-tilts, warning decision was made for large hail and wind.

The PGHG flash densities spiked at 66/min at 1906z

Meanwhile, the ProbSevere also was increasing. After remaining steady at 20%, it jumped to 80 percent then maxed out around 90 percent.

On the other CAVE perspective, the KHGX radar data showed a weak hail spike at the 5.1 degree slice. The Z/CC showed this fairly well.

The combination of the ProbSevere, PGLM lightning densities and the radar data provided enough confidence to go with a warning.

George

The top image below is SRSOR Visible at 1820UTC. The second image is regular GOES Visible at 1745UTC. There was a lot of useful information available in the rapid scan in between regular GOES scans (in this case 45 minutes between images in AWIPS). The Rapid Scan showed clearing skies south of a cold front  and west of a weak surface low. Briefly following clearing the rapid scan clearly showed growing cumulus/convective initiation along the lines with scalloped area below.   Details of individual cloud elements (including tops quickly blowing off with initial convection) was very obvious in the rapid scan.

While regular GOES imagery reflected the general trends on a larger scale, it did not reflect the extent of clearing skies or convective growth. Evolution on the storm scale is not evident.

-snowstrm

Developing weak convection over HGX area with low flash densities. Comparing two color curves, I prefer the ‘blue to green’ gradients for values less than 10. It was easier to discern the values, especially once values do exceed 10. The other color curve (green to yellow) was harder to distinguish as it went from green to yellow to red back to a yellow color. Granted, this storm is rather weak with low flash densities.

George

2225z super rapid scan with overshooting top (OT) performed fairly well for a long lived cluster of severe storms across southern Oklahoma. However, it missed one persistent OT (circled).