Alert archive / Missouri / Mesoscale Discussions in 2012
Mesoscale Discussion 1697
The Storm Prediction Center issued this mesoscale discussion at Aug 4, 2012, 3:08 AM CDT for 7 counties in Illinois; 13 counties in Missouri. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 4, 2012, 3:08 AM CDT (08:08 UTC)
- Expired
- Aug 4, 2012, 5:15 AM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 20%
Counties Bond County, IL, Calhoun County, IL, Clinton County, IL, Greene County, IL, Jersey County, IL, Macoupin County, IL, Madison County, IL, Audrain County, MO, Boone County, MO, Callaway County, MO, City of Saint Louis, MO, Cooper County, MO, Howard County, MO, Lincoln County, MO, Moniteau County, MO, Montgomery County, MO, Pike County, MO, Saint Charles County, MO, Saint Louis County, MO, Warren County, MO
The radar
The St Louis radar (KLSX), 38 km from the middle of the area, began a volume at 08:11 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
Lincoln, IL (KILX), launched 00:00Z, 8.1 hours before the alert went out and 239 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
- 449 J/kg
- Mixed-layer CIN
- -40 J/kg
- Mixed-layer LCL
- 1801 m above ground
- 0-6 km bulk shear
- 26 kt
- 0-1 km storm-relative helicity
- -8 m²/s²
- 0-3 km storm-relative helicity
- 49 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.3
The text
As transmitted, in the capitals the NWS used until 2016.
596
ACUS11 KWNS 040808
SWOMCD
SPC MCD 040808
ILZ000-MOZ000-041015-
MESOSCALE DISCUSSION 1697
NWS STORM PREDICTION CENTER NORMAN OK
0308 AM CDT SAT AUG 04 2012
AREAS AFFECTED...CNTRL MO THROUGH SWRN IL
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 040808Z - 041015Z
PROBABILITY OF WATCH ISSUANCE...20 PERCENT
SUMMARY...STORMS DEVELOPING OVER CNTRL MO AND EVENTUALLY INTO SWRN
IL MAY PRODUCE ISOLATED SMALL TO MARGINALLY SEVERE HAIL THROUGH THE
EARLY MORNING. AT THIS TIME OVERALL THREAT DOES NOT APPEAR
SUFFICIENT TO WARRANT A WW...BUT AREA WILL CONTINUE TO BE MONITORED.
DISCUSSION...A QUASI-STATIONARY FRONT EXTENDS FROM SRN IL THROUGH
CNTRL MO AND SERN KS. ISENTROPIC ASCENT RESULTING FROM STRENGTHENING
SWLY LLJ HAS PROMOTED THE DEVELOPMENT OF STORMS NORTH OF THIS
BOUNDARY WITHIN A WEAK SHEAR ENVIRONMENT. RESERVOIR OF MODERATE
INSTABILITY EXISTS ACROSS ECNTRL MO INTO SRN IL WITH 1000-1500 CAPE
FOR PARCELS LIFTED FROM AROUND 800 MB. THIS IN CONJUNCTION WITH 7
C/KM 850-500 MB LAPSE RATES MAY SUPPORT A THREAT OF MARGINALLY
SEVERE HAIL WITH ELEVATED MULTICELL STORMS THROUGH THE EARLY
MORNING.
..DIAL/WEISS.. 08/04/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...LSX...SGF...EAX...
LAT...LON 39459035 39078913 38478946 38519099 38609319 39279311
39459035SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 4, 10:26 AM CDT | Mesoscale Discussion | SPC | Adams, Boone, Brown, Bureau, Carroll, Cass and 46 more | 49 min |
| Aug 4, 10:50 AM CDT | Severe Thunderstorm Watch | SPC | Bureau, Carroll, Fulton, Hancock, Henderson, Henry and 16 more | 5 hr |
| Aug 4, 1:09 PM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, DeKalb, DuPage, Fulton and 28 more | 66 min |
| Aug 4, 1:46 PM CDT | Severe Thunderstorm Watch | SPC | Boone, Cook, DeKalb, DuPage, Ford, Grundy and 12 more | 4 hr |
| Aug 4, 3:57 PM CDT | Mesoscale Discussion | SPC | Cook, Lake | 63 min |
| Aug 4, 6:12 PM CDT | Severe Thunderstorm Watch | SPC | Madison, Monroe, Randolph, Saint Clair | 6 hr |
| Aug 4, 5:20 PM CDT | Mesoscale Discussion | SPC | Barry, Barton, Camden, Carter, Cedar, Christian and 38 more | 85 min |
Nearby
Mesoscale Discussions in Missouri, 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.