|
September 15, 2002: End of 14 Sept convective line and Numerous Biological Scatters
Author: Pam Heinselman, CIMMS/OU
Last Updated: 15 April 2003
|
 Forecast/Weather:
|
By 01 UTC September 15, the last convective line has moved through central Oklahoma, and
biological scatterers are observed both ahead of and behind the line. The shortwave
trough responsible for forcing the convective lines also moves across Oklahoma between 00-12 UTC.
Biological scatterers (mostly insects) are observed w/in a large area around KOUN through the
duration of this dataset. Also, two weak cells (2:36-6:31 UTC; Figs. 5-8) and a gust front
(9-10:56 UTC; Figs. 9-16) are observed
north/northwest and south of KOUN, respectively. The cells eventually become obscured by the AP.
Weak echo forms behind the gust front and moves into the AP region as well.
Radar Operations:
|
Start time: 00:56 9/15/02 UTC (19:56 9/14/02 local time)
Stop time: 14:48 9/15/02 UTC (09:48 9/15/02 local time)
Radar/Operational Status:
|
Hydrometeor Classification Algorithm: Cold season
Radar: Calibration appears too high.
Operational Delivery:
|
Snapshots:
|
By 1 UTC 15 September, the convective line has moved through central Oklahoma, and
is arousing biological scatterers both ahead of and behind the southern end of the line (Figs. 1-4).
The HCA classifies the precipitation as snow although this is a rain-only event.
AP is present behind the stratiform region. Later, weak cells are observed north and northwest
of KOUN (Figs. 5-8). The very low ZDR values associated with these cells indicate that a large
number of small drops comprise the meteorological echo (Fig. 6). Shortly thereafter, a gust
front observed south of KOUN, moving northward (Figs. 9-16). Weak echo forms behind this
gust front and moves into the region of AP.
Figure 1: Radar reflectivity at 01:13 UTC 15 September 2002.
|
|
|
Figure 2: Differential reflectivity at 01:13 UTC 15 September 2002.
| |
|
|
Figure 3: Correlation coefficient at 01:13 UTC 15 September 2002.
| |
|
|
Figure 4: Hydrometeor classification algorithm at 01:13 UTC 15 September 2002.
| |
|
Figure 5: Radar reflectivity at 03:26 UTC 15 September 2002.
| |
|
|
Figure 6: Differential reflectivity at 03:26 UTC 15 September 2002.
| |
|
|
Figure 7: Correlation coefficient at 03:26 UTC 15 September 2002.
| |
|
|
Figure 8: Specific Differential Phase at 03:26 UTC 15 September 2002.
| |
|
Figure 9: Radar reflectivity at 09:17 UTC 15 September 2002.
| |
|
|
Figure 10: Differential reflectivity at 09:17 UTC 15 September 2002.
| |
|
|
Figure 11: Correlation coefficient at 09:17 UTC 15 September 2002.
| |
|
|
Figure 12: Hydrometeor Classification Algorithm output at 09:17 UTC 15 September 2002.
| |
|
Figure 9: Radar reflectivity at 10:07 UTC 15 September 2002.
| |
|
|
Figure 10: Differential reflectivity at 10:07 UTC 15 September 2002.
| |
|
|
Figure 11: Correlation coefficient at 09:17 UTC 15 September 2002.
| |
|
|
Figure 12: Specific differential phase at 10:07 UTC 15 September 2002.
| |