CASE 10 - Quasi-linear MCS over SMO, developed MCV

7/21/04

Microphysical scans 0100 - 0415 Z, 3h 15m

(System lifetime: 2200 - 0330 Z)

 

 

 

SYNOPTIC CONDITIONS SUMMARY:

 

 

Synoptic feature map -

IOP status - IOP #3 in effect (see report). This IOP (0Z 7/20-0Z 7/23) captured the breakdown of a monsoon ridge over the domain, along with several wind surges over the GOC including a major Gulf Surge (GS#2). The outflow from this MCS/MCV event was believed to initiate a weak gulf surge in the northern GOC.

 

Most prominent convective activity during this time over the SMO, preceding IV#6.

 

Strong 250mb jet extending from La Paz, Mexico to Texas.

 

 

 

Day 0 forecast discussion text

 

Winds

200 mb - model.ETA.200407210000.00_200mb_wnd.gif

500 mb - model.ETA.200407210000.00_500mb_wnd.gif

700 mb - model.ETA.200407210000.00_700mb_wnd.gif

850 mb - model.ETA.200407210000.00_850mb_wnd.gif

 

Mazatlan SkewT - ops.SkewT.200407210000.Mazatlan_MX.gif

 

 

EVENT SUMMARY: A quasi-linear MCS developed over the SMO between 20-22 Z on 7/20. This MCS moved off the SMO toward the GOC during the observation period, and dissipated shortly thereafter. NOTE: The GOES-10 satellite imagery is missing from 7/20 18Z - 7/21 10Z, making it difficult to describe overall development of system.

 

0100Z, Base reflectivity

 

24 h precipitation totals -

 

S-POL SUMMARY: Scattered intense cells, associated with developing MCS, move through S-Pol domain. Storm motion during this time period was easterly (as are 500mb winds).

 

S-Pol log - spol_072104.txt

 

SCAN OVERVIEW:

 

2000 (7/20) - 0100 Z

Scattered intense cells, presumable associated with developing MCS, developed E of S-Pol over the SMO.

 

2300 Z, Base reflectivity.

 

2315 Z

A cell 80 km to the N-NE of S-Pol had 50-55 dBZ and R-Kdp rainrates of 100 mm/hr.

 

0100 Z

Switched to MicroNear135: Sector centered on 120 deg. Prompted by a particularly intense (63 dBZ) echo that formed just E of S-Pol, moving westward. This cell exhibited good low-level convergence, good upper-level divergence, and frequent lightning (rumbling of thunder noted in S-Pol log).

 

0107Z, dBZ Sector of intense convective activity within MCS over SMO

 

0107Z, dBZ Cross Section through intense cells to east - Corresponds to yellow line drawn on PPI sector above. dBZ in core > 60.

 

0345 Z

Echo intensities have weakened substantially and stratiform precip dominate S-Pol domain.

 

0345 Z, Base reflectivity.

 

0400 Z

End Microphysical Scanning, Switch to ClimoNear: