Alert archive / Iowa / Mesoscale Discussions in 2012
Mesoscale Discussion 1729
The Storm Prediction Center issued this mesoscale discussion at Aug 9, 2012, 5:11 PM CDT for 10 counties in Illinois; 29 counties in Iowa. It was in force for 94 min.
The area
The outline as issued.
The facts
- Issued
- Aug 9, 2012, 5:11 PM CDT (22:11 UTC)
- Expired
- Aug 9, 2012, 6:45 PM CDT
- In force
- 94 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 60%
All 39 counties
Benton County, IA, Black Hawk County, IA, Bremer County, IA, Buchanan County, IA, Butler County, IA, Cedar County, IA, Chickasaw County, IA, Clayton County, IA, Clinton County, IA, Delaware County, IA, Des Moines County, IA, Dubuque County, IA, Fayette County, IA, Grundy County, IA, Henry County, IA, Iowa County, IA, Jackson County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Lee County, IA, Linn County, IA, Louisa County, IA, Muscatine County, IA, Poweshiek County, IA, Scott County, IA, Tama County, IA, Washington County, IA, Hancock County, IL, Henderson County, IL, Henry County, IL, Knox County, IL, McDonough County, IL, Mercer County, IL, Rock Island County, IL, Stark County, IL, Warren County, IL, Whiteside County, IL
The radar
The Quad Cities radar (KDVN), 68 km from the middle of the area, began a volume at 22:14 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The nearest sounding before it
Davenport, (KDVN), launched 12:00Z, 10.2 hours before the alert went out and 74 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 351 J/kg
- Mixed-layer CIN
- -94 J/kg
- Mixed-layer LCL
- 646 m above ground
- 0-6 km bulk shear
- 28 kt
- 0-1 km storm-relative helicity
- 83 m²/s²
- 0-3 km storm-relative helicity
- 130 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.6
The text
As transmitted, in the capitals the NWS used until 2016.
134
ACUS11 KWNS 092212
SWOMCD
SPC MCD 092211
ILZ000-IAZ000-WIZ000-092345-
MESOSCALE DISCUSSION 1729
NWS STORM PREDICTION CENTER NORMAN OK
0511 PM CDT THU AUG 09 2012
AREAS AFFECTED...ERN IA
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 092211Z - 092345Z
PROBABILITY OF WATCH ISSUANCE...60 PERCENT
SUMMARY...A FEW SEVERE STORMS WITH LARGE HAIL AND DAMAGING WINDS ARE
LIKELY...AND A WATCH MAY BE NEEDED SOON.
DISCUSSION...A SHORTWAVE TROUGH WITH MIDLEVEL TEMPS NEAR -15 OR SO
WILL CONTINUE TO DIVE SEWD ACROSS THE UPPER MS VALLEY. AT THE
SURFACE...A BOUNDARY EXTENDED FROM NEAR THE TWIN CITIES SEWD INTO
NRN IL...WITH A SUFFICIENTLY WARM AIR MASS TO THE W TO SUPPORT
SEVERE STORMS. INCREASING SPEED SHEAR WITH HEIGHT IS RESULTING IN
LONG STRAIGHT HODOGRAPHS FAVORABLE FOR SUPERCELLS...WITH COOL AIR
ALOFT FAVORING LARGE HAIL. WITH COLD DOWNDRAFTS...SEVERE WIND GUSTS
MAY OCCUR AS WELL. ANY TORNADO THREAT SHOULD BE BRIEF AND WEAK DUE
TO LACK OF ANY APPRECIABLE LOW LEVEL SHEAR AND SUBSTANTIAL OUTFLOW.
STORMS WILL MOVE RAPIDLY SEWD AND MAY AFFECT THE QUAD CITIES AREA IN
2-3 HOURS.
..JEWELL/CORFIDI.. 08/09/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...ILX...DVN...ARX...DMX...
LAT...LON 41959289 42599294 43149256 43279188 43129135 42639072
42049019 41638969 41108959 40638991 40389064 40339129
40549159 41239238 41959289SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 9, 3:16 PM CDT | Mesoscale Discussion | SPC | Champaign, DeWitt, Douglas, Edgar, Ford, Iroquois and 6 more | 89 min |
| Aug 9, 4:02 PM CDT | Severe Thunderstorm Watch | SPC | Champaign, Coles, DeWitt, Douglas, Edgar, Ford and 8 more | 4 hr |
Nearby
Mesoscale Discussions in Iowa, 2012Mesoscale Discussions in Illinois, 2012Every mesoscale discussion in 2012
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.