A High-OCTANE Way to Start the HWT

 The first day of our Satellite HWT threw us up against the ultimate satellite forecasting challenge - how to analyze severe convection while the local radar is out of service. Specifically, KCYS is out of commission this afternoon while convection is developing off of the Laramie Range.

This presents an interesting challenge for the newest version of LightningCast. LightningCast V1 is a purely satellite-based product that uses four different satellite channels to determine the likelihood of an updraft producing lightning in the next 60 minutes. We’re here this week in part to test Version 2, which uses those same methods but is also trained on several years worth of MRMS isothermal reflectivity at the -10C level. Here’s the issue, though: if KCYS is out of commission, then the closest radar (KFTG) is shooting at 21,000 feet for the 0.5 degree reflectivity scan over Wheatland, Wyoming!

With that in mind, here’s the legacy LightningCast (left panel) vs LightningCast V2 (right panel) as an updraft developed off of the Laramie Range today.

Figure 1: LightningCast probabilities valid at 18:16 UTC on June 1, 2026

Notably, the first lightning strikes came in about 15-20 minutes after the above screenshot. The MRMS-based LightningCast was, if anything, a little more conservative than its no-radar ancestor. It also was struggling to display any reflectivity. You never want to infer a causal relationship based off of one case, but it wouldn’t surprise me if the two are connected.

In another exciting introduction to satellite-based mesoanalysis tools, we got a good look at OCTANE speed/direction tools, which allow us to directly measure the motion of cloud layers that may not be accessible to satellite (eg, the anvil). Below, we are looking at a cluster of severe thunderstorms near Chugwater, Wyoming.

Figure 2: OCTANE Direction product on June 1, 2026

The sharp gradient in greens and oranges is suggestive of divergence within the thunderstorm anvil region - which we would expect to see in an updraft that is evacuating mass toward the tropopause. Even more interestingly, one can see the arced band of inflow clouds/HCRs extending well back into western Nebraska, not just as they feed into the storms, but also as they are literally bent inward by the pressure perturbations. The red hues to the feeder clouds in Nebraska is suggestive of a motion from the southeast, while closer to Chugwater those feeder clouds moved more from the south. We thus know that the thunderstorms are exhibiting a mesoscale influence on their environment.

-Sabrina Carpenter