Suggest Lightning Jump Detection Enhancement

Why not embrace a similar methodology as the prob severe model and use open contours to display lightning jump sigma level versus the current configuration which masks over the data display.

In this case (image below) note how the pertinent and important underlying radar data is blocked out by the lightning jump data display.

Tornadotod

Mercer County WV Severe Thundestorm Warning - Prob Severe Quick Jump!

I issued a Severe Thunderstorm Warning for Mercer County WV, due to a combination of increasing high reflectivity aloft, as well as the Prob Severe model showing a quick jump from 26% at 2031 UTC to 63% at 2034 UTC. These values were not high, but the jump combined with the high reflectivity aloft lead me to issue the warning. The warning was issued at 2039 UTC. Update: 1.75" hail was reported in Mercer County at 2040 UTC. Not much lead time on that storm. JJW

Giles & Monroe County, Virginia Thunderstorm

With steady convection across Virginia this afternoon, we are continuing to evaluate the efficiency of GOES-R and JPSS products in AWIPS-II.

I had a good indication with how this cell would intensify based on the Lightning Jump Detection Algorithm (LJDA) value of sigma 5.0 early on.

Highlighting the lightning jump sigma value in magenta coloring

However, the Prob. Severe Model was not as impressive with data showing a fairly low percentage of 17%. The cell I was tracking earlier in Floyd County had a better percentage highlighted on it.

A few minutes later, the severe probably finally caught up to 74%, but there were already very impressive dBZ values on the cell.

We have been monitoring NWS chat all afternoon from the local WFO and an LSR came down with this cell reporting 1" sized hail in southern Monroe County an inch deep. That was reported at 20z.

1958z radar scan: Seeing the more widespread impressive 75 dBZ values on the border of Giles and Monroe Counties with the 1" hail reported on the LSR at 20z. Additional LSR's came in via chat with golf ball sized hail in Giles County at 2015z and quarter and golf ball sized hail in Mercer County around Princeton at 2040z.

-BW

Franklin County VA Severe Thunderstorm Warning - Prob Severe Jump Delayed.

I issued a Severe Thunderstorm Warning for Franklin County, VA, due to the Prob Severe model showing a gradual upward trend from 55% to 90%. It dropped all the way to 10% at 2016 UTC, then back to 90% at 2019 UTC. This may have been due to Prob Severe detecting "Mature Storm" for the growth and glaciation rates at 2014 UTC (Prob Severe was 75%). This perhaps limited its ability to sample those rate values at 2016 UTC. All tilts was showing a potential three body scatter spike with this cell, so that helped me issue the warning before the Prob Severe model spiked up to 90% at 2019 UTC. Update: 1.00 inch hail was reported in Franklin County at 2020 UTC, and Ping pong ball size hail at 2025 UTC. JJW

Floyd County, Virginia Thunderstorm

I evaluated a thunderstorm that increased in intensity on the borders of Carroll and Floyd counties with some of the products we are evaluating this week.

I found that the Lightning Jump Detection Algorithm (LJDA) or the magenta coloring helped with detecting the increase in strength of the storm as dBZ intensified when it crossed into Floyd County. The sigma value on the jump went to 5.0 quickly, which gave me a good sense of the cell's health.

The Prob. Severe Model was also overlayed and gave me an excellent sense that this cell would become severe as it entered into Floyd County. It had an 89% probability on it on the border of the counties.

We were monitoring NWS Chat and an LSR from the public came down at 1922z of quarter sized hail in Floyd County.

In conclusion, the LJDA and the Prob. Severe Model products I overlayed on this cell handled the situation well with the severe thunderstorm.

Screenshot from AWIPS-II / Radar from 1903z

-BW

Giles County VA Severe Thunderstorm Warning - 2 Sigma Lightning Jump But Delayed Prob Severe Jump.

I issued a Severe Thunderstorm Warning for Giles County, as this cell showed a three body scatter spike on the all tilts reflectivity product. The Prob Severe model did not show much, as it was mainly between 20% and 25% for the past 10 minutes or so. There was a 2 sigma lightning jump (not shown) with this cell, which combined with the low Prob Severe values would not have alerted me to this cell as being potentially severe. Update: The Prob Severe values jumped to the 75% to 80% range about 5 minutes after I issued the Severe Thunderstorm Warning. Classic three body scatter spike with this cell. 1.00 inch hail up to 1 inch deep in far southern Monroe County (in warning) at 2000 UTC. Also, 1.75 inch hail in Giles County at 2015 UTC. JJW

LAP Data Showing Increasing Instability

NUCAPS 17Z Sounding near KIAD

KIAD 12Z Sounding

We are focused on the Sterling, VA CWA for future convective initiation. Currently, skies are mostly clear allowing for ample daytime heating. This is first evident in the comparison of the 12Z KIAD Sounding with the 17Z NUCAPS Sounding (shown above)...with the NUCAPS sounding showing a well-mixed layer and plenty of available energy for convective development. Additionally, the LAPS data is showing increasing instability in this area with CAPE values reaching 1000 J/kg, LI values nearing -5 and TPW in excess of 1.0". Below is an animation showing the increasing instability within the LAPS data.

~Lilly Miller~

Floyd County VA Severe Thunderstorm Warning - Prob Severe Jump Due To Flash Rate Jump.

I issued a Severe Thunderstorm Warning for Floyd County VA, due in part to the Prob Severe Model showing a dramatic increase from 48% at 1901 UTC to 91% by 1911 UTC. The only real change was a quick increase in the flash rate, which increased from 8 to 47 flashes per minute. This, along with using the all tilts reflectivity, gave me increased confidence to issue the Severe Thunderstorm Warning. Update: 1.00 inch hail reported at 1922 UTC with this storm. JJW

Destabilization Underway Across LWX CWA

GOES SRSOR imagery along with GOES CI product showing congested cumulus development over wrn/cntrl portions of LWX CWA in advance of upper disturbance lifting out of the TN valley.  Note the lower to moderate bound probs of CI now taking shape immediatedly upstream over srn RLX CWA.

Based on recent sfc modified NUCAPS sounding, expect convn will develop soon over swrn portions of the CWA.  Modest instability and increasing shear ahead of sw trough will bring a slight chance for severe storms later this aftn.  Will cont to monitor...

Tornadotod

Week 3 begins!

Week 3 of the HWT GOES-R/JPSS Spring Experiment has begun. We start this week where we ended last week - the Mid-Atlantic. The two groups are operating in the Sterling and Blacksburg CWA's. Below is a recent GOES-14 1-min visible animation of the region.