CASE 18 - Long-lived, right-turning MCS develops E of S-Pol

8/5/04

Microphysical scans 1930 - 2130 Z, 2h

(MCS lifetime: 1930 - 8/6 1100 Z)

 

 

SYNOPTIC CONDITIONS SUMMARY:

 

Synoptic feature map - MISSING

 

Day 0 forecast discussion text

 

Winds

200 mb - model.ETA.200408060000.00_200mb_wnd.gif

500 mb - model.ETA.200408060000.00_500mb_wnd.gif

700 mb - model.ETA.200408060000.00_700mb_wnd.gif

850 mb - model.ETA.200408060000.00_850mb_wnd.gif

 

Mazatlan SkewT - ops.SkewT.200408062100.Mazatlan_MX.gif

 

EVENT SUMMARY: A quasi-linear / asymmetric MCS developed over the SMO just N of Mazatlan, propagated towards S-Pol, and then moved NW along the coastal plain.

 

24 h precipitation totals -

 

 

TIMELINE OF DEVELOPMENT:

 

1930 Z

Deep convection initiates to the E of S-Pol, along the SMO.

 

1940Z, GOES-10 Vis

 

2030 Z

Deep convective region to the E of S-Pol growing, look more organized.

 

2024Z, GOES-10 Vis

 

2230 Z

Leading convective region takes on a linear shape w/ a trailing stratiform region to the E.

 

2224Z, GOES-10 Thermal IR

 

2300 - 8/6 1130 Z

MCS turns to the right, moving N/NW. The MCS maintains a leading convective line/complex with a trailing stratiform region (to the S/SE). Main convective activity has dissipated by 1130 Z.

 

0324Z, GOES-10 Thermal IR

 

0724Z, GOES-10 Thermal IR

 

1124Z, GOES-10 Thermal IR

 

 

 

S-POL SUMMARY:

 

S-Pol log - spol_080504.txt

 

SCAN OVERVIEW:

 

1900 Z

Switching to ClimoFar: Cells coming into radar range at 150-180 km to the east. Cells were not being topped with ClimoShallow.

 

1900Z, Base reflectivity

 

1930 Z

Begin Microphysical Scanning, Switching to MicroFar90: Sector centered at 80 deg to capture convection coming into range from the east.

 

1930Z, Base reflectivity

 

2035 Z

Switching to MicroNear90: Convection is now being topped.

 

2045 Z

Switching to MicroNear135: Convection breaking out over the foothills. Log notes an interesting altocumulus deck over S-Pol. Running RHIs at 102 and 103 deg. Convection along leading line of MCS appears to be elevated (67 dBZ core at 7 km).

 

2100Z, Base reflectivity

 

2130 Z

End Microphysical Scanning, Switching to ClimoNear: Echo coverage is too great to focus on sectors.

 

2205 Z

Light rain at S-Pol, dissipating by 2250 Z. MCS turning right, moving N along coastal plain.

 

2200Z, Base reflectivity

 

2300 Z

Running Profiler Scans: Leading convective line passing NOAA profiler site. 40 dBZ @ profiler.

 

2315 Z

Classic MCS (asymmetric) moving N along coastal plain - trailing 40 dBZ stratiform stretched south of radar. Nice rear inflow jet on velocity signature. 20 m/s jet between 2-3 km from ENE behind systems. Surface divergence present at radar.

 

2315Z, Radial velocity