Storms in the area this afternoon were mainly low-topped supercells with neutral values of speed (green) with a weaker sheared environment. The main thing that was noticeable was the threshold for CTD was not very strong with the storms this afternoon in the area (Figure 1). Thus, adjustments were made to the colorbar maximum thresholds with CTD for each smoothing technique (see Figure 2). The highest smooth CTD is normally 4, so it was maintained. Meanwhile, the medium smooth CTD was lowered to 3 as the colorbar maximum value and the regular CTD (non-smoothed) colorbar maximum was lowered to 2. The intensity of CTD becomes more notable in the lower thresholds, which may be needed/more helpful in these low-topped storm modes where the updrafts and cloud tops are not going to be near as cold (higher in altitude) as other convective modes. More research may be needed to look into whether the storm that originally created subtle CTD values (before the adjustment to the colorbar) ended up going on to become severe and/or produce hazardous weather. Therefore, local calibration may be needed by offices when it comes to different convective modes.
Figure 1: OCTANE Speed/Direction and CTC/CTD.
Figure 2: OCTANE Speed/Direction and CTC/CTD with adjusted colorbar maximum values for CTD across all smoothing levels.
Lightning cast V1 showed slightly lower probabilities than V2 for the convective initiation mentioned above.
Figure 3: Lightning cast V1 (left) and V2 (right) with GLM Flash Extent Density and Day Cloud Phase Distinction RGB.
– Aurora Borealis
