CI 15 minute lead time

CI at 2045UTC showed areas in LUB CWA with 83% and 87% probability of initiation. Both of these developed into cells at 2100UTC.

-snowstrm

Region of potential development

This region of partly cloudy skies in the northwest section of the DFW CWA remains relatively untapped.  Latest GOES-R super rapid scan shows more clearing in this area and will monitor for potential development.  NUCAPS data after modification shows steep low level lapse rates…so convective initiation should be rather easy.

West Texas Soundings

First try at comparing modified soundings.

1. 12Z Midland RAOB modified to 30/18, yielding 4250 SBCAPE (3800 with ob at time of earlier NUCAPS)

2. Afternoon NUCAPS nearest LBB modified to 26/19, yielding 3900 SBCAPE

3. LBB is appx 125 mi N of MAF, but in reasonably similar environment.  Despite other differences, feature at 700 mb appears in both.

-Holaday

2000z – Ellis County Tornado report

A tornado was reported in Ellis County with tstm near Waxahatchie around 2019z. Due to distance from kdyz radar…we were overshooting the low-level rotational signature. This storm had about 55dbz reflectivity at -20c. Since it was a marginally severe storm…with uncertainty on rotation…no warning was issued.

Possible EWP clues…

GOES R superscan did indicate a strong updraft with visible overshooting tops…although not picked up GOES CI and overshooting top detection.

At 1936z…ENI DTA was alerted on this storm…but CIMSS prob svr never increased more than 20 percent.

ENI flash rate trace below…showed a rapid doubling in lightning btwn 1940 and 1950z…indicating transition from an ordinary cell to a supercell. The tornado report was during the down trend in lightning. Previous studies have shown that this could be a possible time for tornado development as the storm weakens and rfd collapses.

So GOER R superscan, ENI lightning rate trace, and DTA could have been useful signals to warn on this marginally severe storm development. The ENI lightning trace could have pointed towards potential for tornadogenesis…based on conducive environment and possible weak boundary.

Pickles

Lightning Jump Success

The Lightning Jump Detection Algorithm indicated a sigma of 5.00 at 2009UTC (see below).  This was proceeded by a sigma of 4.00. A tornado was reported at 2030UTC, 21 minutes after the 5 sigma, a successful case of predicting a severe.

Meanwhile, the ProbSevere product showed  54% at 2030UTC then peaked at 74% at 2032UTC. This was after report of the tornado.

-snowstrm

Missing CI in multiple cloud layer decks

The GOES-R CI algorithm has trouble detecting Convective Initiation when there are clusters of clouds of multiple levels in the same area. Two areas of initiation occurred today, one near the Red River, and one near the south of the Dallas/Fort Worth area where multiple decks of clouds prevented the CI product from tracking the cells. The CI algorithm requires at least 10% overlap of objects between two successive time periods, and without being at the office to look at the overlap, it is not known if these were missed due to mistracking or if the algorithm just did not detect convective clouds due to the multiple cloud layers. Something we will need to look into for the future. In the scalloped areas from 1900 UTC and 2000 UTC, one can see the difficulty of pulling out distinct features in the visible imagery, yet by 2000 UTC, full blown thunderstorms had developed.

Prob severe rate

Issued severe thunderstorm warning for hail.  Prob severe ranged from 90 to a maximum of 94%, which lined up well with with my warning thoughts.

ProbSevere 5.69″ MESH

The ProbSevere  jumped up to 96% with MESH over 5″ when ABQ radar went into clear air mode for 2 scans.

-snowstrm

2000z FWD

GOES CI is picking up on CI across west central portions of the cwa…but interestingly enough not picking up on the circled likely severe cell and cell to its ne below. Prob severe of 80% and DTA detected at 1930z. (Fig2)Overshooting top detection has not picked up on this cell either. The GOES-R superscan (Fig 1) is very nicely showing the overshooting top on this and cell to the ne.

Storm Pulsing Back Up Over OUN CWA

Using ProbSevere and the ENI lightning flash rate time series, I issued a new SVR warning. I like having both data side by side to add confidence when examining the raw radar data. This storm has pulsed up and down over the last hour or two, so the ProbSevere helps keep the SA up when it maxed out at 80% when I issued the warning.