Alert archive / Illinois / Mesoscale Discussions in 2012
Mesoscale Discussion 615
The Storm Prediction Center issued this mesoscale discussion at Apr 28, 2012, 6:12 PM CDT for 9 counties in Illinois; Jefferson County, Missouri. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 28, 2012, 6:12 PM CDT (23:12 UTC)
- Expired
- Apr 28, 2012, 8:15 PM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
Counties Franklin County, IL, Hamilton County, IL, Jefferson County, IL, Monroe County, IL, Perry County, IL, Randolph County, IL, Saint Clair County, IL, Washington County, IL, Wayne County, IL, Jefferson County, MO
The radar
The St Louis radar (KLSX), 118 km from the middle of the area, began a volume at 23:15 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 12:00Z, 11.2 hours before the alert went out and 231 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1019 m above ground
- 0-6 km bulk shear
- 63 kt
- 0-1 km storm-relative helicity
- 681 m²/s²
- 0-3 km storm-relative helicity
- 811 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 2.0
The text
As transmitted, in the capitals the NWS used until 2016.
161
ACUS11 KWNS 282312
SWOMCD
SPC MCD 282312
ILZ000-MOZ000-290115-
MESOSCALE DISCUSSION 0615
NWS STORM PREDICTION CENTER NORMAN OK
0612 PM CDT SAT APR 28 2012
AREAS AFFECTED...ERN MO...SWRN IL
CONCERNING...TORNADO WATCH 199...
VALID 282312Z - 290115Z
THE SEVERE WEATHER THREAT FOR TORNADO WATCH 199 CONTINUES.
A SUPERCELL WAS MOVING FROM NERN WASHINGTON COUNTY INTO JEFFERSON
COUNTY MO...AND WILL LIKELY PERSIST ACROSS MONROE AND RANDOLPH
COUNTIES IN IL.
SURFACE ANALYSIS SHOWS AN OUTFLOW BOUNDARY FROM EARLIER ACTIVITY
FROM SRN ST. CLAIR COUNTY IL INTO MONROE COUNTY. AS THIS PARTICULAR
STORM CONTINUES ENEWD...IT MAY BENEFIT FROM ENHANCED LOW LEVEL
VORTICITY WITH THE POSSIBILITY OF A TORNADO.
..JEWELL.. 04/28/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...PAH...LSX...
LAT...LON 37918903 37939043 38079079 38329069 38419036 38508997
38518895 38448841 38148832 37978838 37918903SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 28, 1:17 PM CDT | Mesoscale Discussion | SPC | Bond, Calhoun, Clay, Clinton, Crawford, Cumberland and 24 more | 88 min |
| Apr 28, 1:48 PM CDT | Severe Thunderstorm Watch | SPC | Bond, Calhoun, Clark, Clay, Clinton, Crawford and 20 more | 7 hr |
| Apr 28, 2:56 PM CDT | Mesoscale Discussion | SPC | Bond, Clark, Clay, Clinton, Crawford, Cumberland and 13 more | 64 min |
| Apr 28, 5:15 PM CDT | Tornado Watch | SPC | Clinton, Edwards, Franklin, Gallatin, Hamilton, Jackson and 12 more | 5 hr |
| Apr 28, 5:59 PM CDT | Mesoscale Discussion | SPC | Bond, Calhoun, Clark, Clay, Clinton, Crawford and 20 more | 2 hr |
| Apr 27, 7:00 PM CDT | Mesoscale Discussion | SPC | Andrew, Buchanan, Caldwell, Cass, Clay, Clinton and 6 more | 30 min |
| Apr 27, 7:18 PM CDT | Severe Thunderstorm Watch | SPC | Bates, Buchanan, Cass, Clay, Clinton, Jackson and 1 more | 95 min |
Nearby
Mesoscale Discussions in Illinois, 2012Mesoscale Discussions in Missouri, 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.