CASE 30 - Leading line
MCS develops over SMO to the SE of S-Pol, tracks over GOC
Microphysical scans 0230 - 0400 Z, 2h
SYNOPTIC CONDITIONS SUMMARY:
MCS
Track Map -
Active weather day -
abnormal northwesterly upper flow event (see Day 0 discussion for details
relevant to activity in Upper flow between
trough axis to the N and sub-tropical ridge situated W of Baja provided
favorable upper diffluent pattern.
Day
0 forecast discussion text
Winds
200
mb - model.ETA.200408170000.00_200mb_wnd.gif
500
mb - model.ETA.200408170000.00_500mb_wnd.gif
700
mb - model.ETA.200408170000.00_700mb_wnd.gif
850
mb - model.ETA.200408170000.00_850mb_wnd.gif
MESOSCALE SUMMARY:
2240Z, GOES-10
24
h precipitation totals -
ROUGH
TIMELINE OF DEVELOPMENT:
|
8/16
2245Z |
Linear
MCS forms over mountains at the far SE end of S-Pol scope. |
|
8/17
0000Z |
System
has lost some of its linear organization. |
|
0230
Z |
System
is a leading-stratiform trailing stratiform system, spanning ~60 km. |
|
0230
- 0830 Z |
MCS
propagates westward over the GOC. Oceanic convection develops in front of
leading line as cold pool spreads over GOC. |
S-POL SUMMARY:
S-Pol
log - spol_081704.txt
SCAN
OVERVIEW:
|
8/16
2246 Z |
Nice
little linear MCS popping up well to the SE. Started over the mountains. 2245 Z, Base reflectivity
|
|
0000
Z |
The
NE nearby echoes are some of the best-looking ones out there at this time.
Visually, the cloud is not too shabby either. 0000Z, Base reflectivity
|
|
0100
Z |
The
0100Z, Base reflectivity |
|
0130
Z |
Switching to ClimoFar: Nearby NE cells dissipating. |
|
0230
Z |
Begin Microphysical Scanning, Running
PPIs as part of a test sequence, similar to MicroFar135 but at 720 Hz and
with a 120 deg sector (center is 90 deg): Focus is on the MCS to the SE, which sprawls off scope too much to
scan well at 960 Hz. RHIs on NW-SE line of cells near 135 deg. PPIs will miss
the only other game in town, a distant storm over the sea due south and near
the edge of the scope. Angles are designed to top 15 km AGL at 60 km range,
w/ 1.1 km vert res. 0230Z, Base reflectivity
|
|
0245
Z |
MCS
is basically LLTS form, sprawling from about 60 km from the radar to the edge
of the scope. |
|
0300
Z |
Sectors
are really working out well - geometry of system is making scanning it pretty
straightforward. A very nice looking MCS right now. Movie loops reveal SE
portion of line moving out to sea. 0300Z, Base reflectivity
|
|
0330
Z |
Nice
phase shifts thru SE line due to alignment along radial. RHIs to cell near
108 deg that I have had a hard time topping. 0330Z, Base reflectivity
|
|
0405
Z |
The
leading line convection close to the radar is being topped at 19.2 degrees.
Oceanic convection to the south is really being missed because it's outside
the sector. Keeping with the main event for the time being. 0400Z, Base reflectivity
|
|
0415
Z |
The
oceanic convection appears to be developing its own leading convective line
which we're missing with the sector scan. The main leading-line system is
getting to be larger than the 120 degree sector. RHIs remain at 150 and 152
degrees through the leading line. 0415Z, Base reflectivity
|
|
0430
Z |
End Microphysical Scanning, Switched
to ClimoFar: Switched to capture
all events. Climofar was chosen rather than climonear to keep the vertical
resolution at the far side of the system without loosing too much of the tops
of the near side of the system. The close cells are 25km from the radar. The
main system has sent out a few cold pools over the ocean, and one has
triggered another line of cells ahead of the original line. One of the cold
pools is heading over SPOL about now. Windy outside (15-20mph gusts), temp
82f Td 77f. 5 minutes later the Td had dropped to 72f. 0430Z, Base reflectivity
|
