CASE 31 - Mature to decaying stages of a weakly organized system that developed 100km N of S-Pol

8/17/04

Microphysical scans 1400 - 1615 Z, 2h 15m

 

 

SYNOPTIC CONDITIONS SUMMARY:

 

 

 

Tier 1 under northwesterly upper flow regime - rare for mid-August.

 

NWly flow did not appear to alter the convective cycle over Mexico.

 

Day 0 forecast discussion text

 

Winds

200 mb - model.ETA.200408171200.00_200mb_wnd.gif

500 mb - model.ETA.200408171200.00_500mb_wnd.gif

700 mb - model.ETA.200408171200.00_700mb_wnd.gif

850 mb - model.ETA.200408171200.00_850mb_wnd.gif

 

 

 

MESOSCALE SUMMARY: A convective system developed out of range of S-Pol to the NW at ~0930Z, propagated vert slowly to the SE. System peaked around 1130 Z, continued to dissipate. Around 1345Z, new development was triggered to the SW of the dissipating system (over the GOC), at ~100 km to the N/NW of S-Pol. This cell intensified over the GOC, moving almost due S, until it dissipated by ~1600Z.

 

1424Z, GOES-10 Vis

 

24 h precipitation totals -

 

S-POL SUMMARY:

 

S-Pol log - spol_081704.txt

 

SCAN OVERVIEW:

 

0600 - 1230 Z

Convective activity has been flaring and redeveloping to the N/NW of S-Pol beyond 140 km.

 

0830Z, Base reflectivity

 

1245 Z

Switching to ClimoFar: System to the N looks more convective.

 

1245Z, Base reflectivity

 

1300 Z

Cell at 300 deg at ~100-120 km intensifying. Core of 45 dBZ extends to 14 km.

 

1300Z, Base reflectivity

 

1400 Z

Begin Microphysical Scanning, Switching to MicroFar90: Centered on cell to the W/NW at 100 km range. Cell approaching 55 dBz at 1.98 deg elev angle. Large anvil blowoff.

 

1400Z, Base reflecitivity

 

1445 Z

Recentered sector at 280 deg. Storm is moving due S, currently E of S-Pol at 70 km. Mid 50ís dBZ and signature of ZDR column.

 

1445Z, Base reflectivity

 

1521

Storm is decaying, but there is new intensification just north of the original cell. Still a large cirrus shield. Still in MicroFar90 centered on 280deg.

 

1515Z, Base reflectivity

 

1536

System has pretty much died, but for now we will remain in microphysical mode incase things reintensify. Will reevaluate in about 30 minutes.

 

1530Z, Base reflectivity

 

1615 Z

End Microphysical Scanning, Switching to ClimoFar: Remnants to the E are dissipating, only anvil left.

 

1615Z, Base reflectivity