KOUN Convective Line: May 27, 2002

May 27, 2002: "Splitting" Convective Line with AP behind it

Last Updated: 23 April 2003

Forecast/Weather:

On 27 May 2002, a long line of convective cells, initially spanning from north to south across western Oklahoma, moves toward central Oklahoma. As the line approaches KOUN, it begins to split, with the northern half moving northeastward, and the southern half moving southeastward (Figs. 1,4,7,10). Some of these cells produce heavy rain (Fig. 10). Interestingly, polarimetric signatures behind convective cells near the northern OK border indicate a mix of hydrometeors, possibly including tumbling hail (note pockets of low ZDR associated with the absence of KDP in Figs. 1,10). Following the passage of these lines, AP occurs around KOUN, and just behind the southeastward-moving line (Figs. 2,5,8). The polarimetric signatures make it easy to differentiate between the AP and the weather signal (cf. Fig. 2 with Figs. 5,8,11). After these lines move out of range, a new region of light precipitation moves across southern Oklahoma, and a group of multicellular storms develops east of KOUN (Figs. 3,6,9,12).

Radar Operations:

Radar/Operational Status:

Operational Delivery:

Not applicable.

Snapshots:

Figure 1: Reflectivity at 5:21 UTC 27 May 2002.

Figure 2: Reflectivity at 9:19 UTC 27 May 2002.

Figure 3: Reflectivity at 15:43 UTC 27 May 2002.

Figure 4: Differential reflectivity at 5:21 UTC 27 May 2002.

Figure 5: Differential reflectivity at 9:19 UTC 27 May 2002.

Figure 6: Differential reflectivity at 15:43 UTC 27 May 2002.

Reflectivity

Figure 7: Correlation coefficient at 5:21 UTC 27 May 2002.

Figure 8: Correlation coefficient at 9:19 UTC 27 May 2002.

Figure 9: Correlation ceofficient at 15:43 UTC 27 May 2002.

Reflectivity

Figure 10: Specific differential phase at 5:21 UTC 27 May 2002.

Figure 11: Specific differential phase at 9:19 UTC 27 May 2002.

Figure 12: Specific differential phase at 15:43 UTC 27 May 2002.

Hydrometeor Classification

Figure 4: Caption