Taking a look at OCTANE – it seems like the IR/Nighttime data shows especially the directional details a bit more than the Visible/Daytime products. This has been a continuing trend this week. The CTD and CTC products have been useful with monitoring the strength of the storms (especially which may become severe) as well as with the newer convection/updrafts.

OCTANE – Visible (Daytime) vs IR (Nighttime)

OCTANE – Cloud Top Cooling and Cloud Top Divergence

Forecaster Cumulus

Here is a good example of the OCTANE product showing the transition from an updraft to a divergent anvil cloud, which then cuts off from the parent updraft. This “orphan” anvil is an indication of a convective initiation attempt, which can be a signal for upcoming successful initiation in the near future. The OCTANE product does well to highlight both the updraft and then the anvil in different color shades through the entire orphan anviling process.

Wanted to make some observations comparing the day and night versions of OCTANE with convection in the KSJT forecast area. This is at about 1837Z.

For the most part, want to compare the speed product (left side) with the storm near Taylor County (bottom left part of the image). The day version is in the top left, and the night version is in the bottom left. There is detail in the day version that does not carry through to the night version. Of note: the anvil-top cirrus (slower motions) do not show up on the night version. Also, the magnitudes of the north and south lobes of higher speeds are muted somewhat on the night version.

Also want to note that the night version of the direction product (bottom right) shows a more significant shift in direction than the day version (top right). This is most evident with the larger shield of clouds over the top right part of the field of view, where more orange colors (about 200deg) are showing up on the northwest flank than in the day version (210deg-220deg). This is also evident somewhat on the storm in the bottom left part of the image.

It was also noted that overshooting tops in the night speed product appear as dark spots, which appears to be related simply to the IR  depiction of the storm. This is not a problem, as it draws the eye to the overshooting top / strong updraft.

–Insolation

A number of features appear differently on IR and visible based OCTANE products this afternoon. First, the divergence of cloud top motion really stand out on the IR products, especially on the southwest storm in SJT’s CWA. The dark blues on the upshear side as well as the contrast of the red and green directional colors really appear well on the IR. In comparison, the visible based OCTANE speed product still shows shows the upshear values with the divergence signal, though it is a bit more subtle than IR. However the visible product allows us to see other features, like the above anvil cirrus plume on the southwest storm. In the cluster of storms to the northeast where this kind of feature isn’t visible, the visible OCTANE product still shows the strong cloud top divergence. OCTANE direction from IR shows divergence aloft a bit better than the visible product, though the difference isn’t huge. Finally, the color table adjustments done today to the Octane Speed IR product really help make the divergence stand out. Cloud top divergence in these products has been pretty well correlated with thunderstorm severity, so the IR based product seems like it would be very useful, especially at night.

-Joaq

On the warning desk today, I’ve noticed that I have been using OCTANE the most out of the newer tools (besides an adjacent radar). It has really helped with confidence with warning decisions – are the storms maintaining strength… are newer ones growing? The storm in the eastern portion of this loop (below) has been going and going for a handful of hours (originally SVR in our area). OCTANE has kept right along with it and showing its evolution aloft (in both IR and Visible).

 

These products have aided in confidence in warning ops, especially with lack of primary radar.

Forecaster Cumulus

The distribution characteristic of the derived cloud top divergence product has been helpful in highlighting potentially severe thundretsorms. Here the purple/pink colors are fairly consistent compared to the more “broken” distribution of colors to the east. Additionally, cloud top cooling is appearing as an overshooting top (and continued to reappear after this animation ended). Even if radar data was absent the severity of the thunderstorm would be apparant. A warning was issued on this storm (shown below).

-Joaq