January 12, 2003: Light Snow from 3 Snowbands Author: Pam Heinselman, CIMMS/OU Last Updated: 4 April 2003

Forecast/Weather:

Three snowbands develop on 12 January 2003 (see Figs. below). Oklahoma City reported a trace of snow from this event. When data collection begins (04:41 UTC) two linear bands are located in southern Oklahoma, where one band is oriented in the west-to-east direction and the other is oriented along the southwest-to-northeast direction. The west-to-east-oriented band moves northeastward across central Oklahoma (04:41-11:07 UTC), while snow cells move northeastward along what appears to be a quasi-stationary boundary (04:41-13 UTC). The third snow band develops by 6:09 UTC west of KOUN. This band is also oriented along the southwest-to-northeast direction, and is quasi-stationary with "training" snow cells moving toward the northeast. The two longitudinally-oriented bands begin to move eastward between 13-14 UTC, suggesting the eastward movement of a trough in the westerlies.

Radar Operations:

Start time: 04:41 01/12/03 UTC (22:41 01/12/03 local time)
Stop time: 22:45 01/12/03 UTC (16:45 01/12/03 local time)

Radar/Operational Status:

Hydrometeor Classification Algorithm: Cold season

Operational Delivery:

Not applicable.

Snapshots:

Figure 1a: Radar reflectivity indicates two linear snow bands at 5:19 UTC in southern Oklahoma (one west-to-east oriented, the other southwest-to-northeast oriented).	Figure 1b: Radar reflectivity indicates three snowbands at 9:15 UTC. The southwest-to-southeast- oriented bands are quasi-stationary.	Figure 1c: Radar reflectivity shows that the snow bands have begun moving eastward (14:11 UTC).
Figure 2a: Small-to-slightly negative differential reflectivity values indicate ice and/or snow at 5:19 UTC.	Figure 2b: Small-to-slightly negative differential reflectivity values indicate ice and/or snow at 9:15 UTC.	Figure 2c: Small-to-slightly negative differential reflectivity values indicate ice and/or snow at 14:11 UTC.
Figure 3a: The hydrometeor classification algorithm classifies precipitation as dry snow at 5:19 UTC.	Figure 3b: The hydrometeor classification algorithm classifies precipitation as dry snow at 9:15 UTC.	Figure 3c: The hydrometeor classification algorithm classifies precipitation as dry snow at 14:11 UTC.