I had been noticing a gradual increase in ProbSvr and at 2134Z, it reached 79%. At the exact same time, I got a 2 sigma lightning jump. This increased my confidence that the storm was intensifying and that a severe thunderstorm warning was needed. I went ahead and issued the warning based on ProbSvr and Lightning Jump alone. After the warning was out, the prob severe continued to increase to 94%. The WFO has not issued a warning on the storm. It will be interesting to see whether or not it verifies.

-Helen Hunt

Sustained total lightning as indicated by surface flash density and CIMSS prob severe model 99% indication on the cell west of Limon, CO. MESH is topping out around 1.25 inches.  Due to the sustained high lightning activity lightning jump sigma levels remain  around 1 or less.  I min visible imagery shows a developed inflow region marked by low level cu field streaming into the southeast flank of the cell.

John Pendergrast

GOES-14 1-minute visible satellite data showed a towering cumulus that tried to grow across southern portions of Greenley county at 2050 UTC…

which started to build nicely over the next 10 minutes…

and grew further, showing what looked like a nice anvil top at 2110 UTC.

However, the low level southeast winds clashed with the stronger mid level southwest winds, which tore the top of the thunderstorm away from the low level convection just 10 minutes later.

A light shower was noted on KGLD radar at 2118 UTC near the southern Greenley county border that quickly dissipated.

CoonieCatEye/Jason Williams

Upper Left: is the Boulder Regional Flash Exent, Upper Right: 1 Min Vis imagery along with CIMSS Prob Severe Model, Lower left: Lightning Jump, Lower Right:  0.5 deg Reflectivity.

John Pendergrast

Just an FYI, probably saw the highest CI I’ve seen since I’ve been here (90% eastern Osborne CO).  Went on to just be run of the mill cu with no radar reflectivity seen. I continue to monitor CI but it has not instilled much confidence this week. –Cattywampus

Fig 1: 90% CI in eastern Osborne Co.

Was monitoring a developing cell mainly with base/dual-pol data. Was on the edge of a warning decision and looked to ProbSevere for added confidence. During the 20:08z scan had a ProbSevere of 54% (fig 1) with no growth of glaciation rate. During the subsequent 20:10z scan the cell merged with the northern cell and quickly jumped to 84% (fig 2). Lost confidence in this prob due to the merger. Ended up warning on base data info along and just the trend of the increasing ProbSevere from the previous scans. –Cattywampus

Fig 1: 20:08z ProbSevere 54%

Fig 2: 20:10z ProbSevere 84%, Cell Merger

This is an example where the CI product performed very well. At 1915Z, the CI probability increased from nothing to 61% (yellow) and 70% (yellow-orange) over two spots in the Boulder FA. In the next satellite scan (15 min later), you can see the significant cloud growth that occurred in the exact area where the 70% CI product had been. This storm continues to grow in the proceeding images and eventually becomes severe. The cell that showed 61% CI also intensifies significantly, but it takes a little longer (about an hr).

I was pretty pessimistic about the CI product after using it yesterday in the southeastern part of the country where there were widespread discrete and multicells. There were so many areas that the CI picked up on that it just become too busy to be of much use to me. However, my faith has been restored in the CI product after seeing how well it is performing out west today. I think that the utility of the product will depend on the type of the convection expected and the coverage of the expected convection.

(Click image to see animation)

-Helen Hunt

Cell tracking is inherently difficult, here is an example of how it can lead to conflicting data. Notice the two cells to the in the upper left image.  These cells congeal in the image below.

We both had timeseries set on the individual cells above.  When they combined the resulting time series of each did not seem to match each other.

What this means is that when you are looking at time series of merging storms, you will need to reset your point for the time series to work and be aware of what is going on when you use the data.

MacGyver and Cattywampus

I call the image below the ‘Ultimate 4-Panel Display’. I probably would have incorporated the ENI data somewhere into my display, but I wasn’t allowed to use it. This 4-panel might be a good recommendation for forecasters.

Upper Left: PGLM Surface Flash Density w/ range rings

Upper Right: GOES 1-min Vis w/ CI

Lower Left: Lightning Jump

Lower Right: 0.5o Reflectivity w/ Prob Severe

-Helen Hunt

GOES-14 1-minute satellite imagery showing bands of cumulus clouds covering most of the CWA early this afternoon. This appears to be inhibiting convection, at least for now.  However, some breaks in those clouds may be moving into eastern areas from KMCK to KHLC.  These areas will need to be monitored for possible towering cumulus development over the next 1-2 hours.

The 1-minute satellite loop shows this nicely.

(Click to animate above image.)

CoonieCatEye/Jason Williams