April 24, 2003: Supercell that later evolves into a bow-shaped echo Author: Pam Heinselman, CIMMS/OU Last Updated: 29 April 2003

Forecast/Weather:

On 24 April 2003, a supercell developed near the southern end of a line of convective cells over south-central Oklahoma (by 1:35 UTC). Polarimetric signatures indicate that heavy rainfall and hail were produced by this supercell as it moved northeastward over primarily Stephens, Garvin, and Pontotoc Counties. By 2:11 UTC, the southern end of the line begins to evolve into a bow-shaped-line of convective cells, initially with strong polarimetric signatures for hail (e.g., 2:41 UTC), that later became a producer of heavy rain only (by 3:20 UTC).

Radar Operations:

Start time: 00:04 4/24/03 UTC (19:04 4/23/03 local time)
Stop time: 11:48 4/24/03 UTC (06:48 4/24/03 local time)

Radar/Operational Status:

Hydrometeor Classification Algorithm: Warm season

Operational Delivery:

TBA.

Snapshots:

This first set of figures shows examples of polarimetric signatures associated with a supercell.

Figure 1: Reflectivity at 1:35 UTC on 24 April 2003.	Figure 2: Reflectivity at 2:15 UTC on 24 April 2003.
Figure 3: Differential reflectivity at 1:35 UTC on 24 April 2003.	Figure 4: Differential reflectivity at 2:15 UTC on 24 April 2003.
Figure 5: Correlation coefficient at 1:35 UTC on 24 April 2003.	Figure 6: Correlation coefficient at 2:15 UTC on 24 April 2003.
Figure 7: Specific differential phase at 1:35 UTC on 24 April 2003.	Figure 8: Specific differential phase at 2:15 UTC on 24 April 2003.
Figure 9: Hail classification algorithm output at 1:35 UTC on 24 April 2003.	Figure 10: Hail classification algorithm output at 2:15 UTC on 24 April 2003.

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Figures below show examples of the "bowing" line of convective cells. The "spike" of low differential reflectivity (Fig. 3), correlation coefficient (Fig. 5), and specific differential phase (Fig. 7) just north of the "bowing" part of the line indicate hail.

Figure 1: Reflectivity at 2:41 UTC on 24 April 2003.	Figure 2: Reflectivity at 3:01 UTC on 24 April 2003.
Figure 3: Differential reflectivity at 2:41 UTC on 24 April 2003.	Figure 4: Differential reflectivity at 3:01 UTC on 24 April 2003.
Figure 5: Correlation coefficient at 2:41 UTC on 24 April 2003.	Figure 6: Correlation coefficient at 3:20 UTC on 24 April 2003.
Figure 7: Specific differential phase at 2:41 UTC on 24 April 2003.	Figure 8: Specific differential phase at 3:20 UTC on 24 April 2003.
Figure 9: Hail classification algorithm output at 2:41 UTC on 24 April 2003.	Figure 10: Hail classification algorithm output at 3:20 UTC on 24 April 2003.