Alert archive / Illinois / Mesoscale Discussions in 2011
Mesoscale Discussion 698
The Storm Prediction Center issued this mesoscale discussion at May 7, 2011, 2:32 PM CDT for 22 counties in Illinois; 10 counties in Indiana. It was in force for 118 min.
The area
The outline as issued.
The facts
- Issued
- May 7, 2011, 2:32 PM CDT (19:32 UTC)
- Expired
- May 7, 2011, 4:30 PM CDT
- In force
- 118 min
- Issued by
- the Storm Prediction Center
All 32 counties
Bureau County, IL, Champaign County, IL, DeWitt County, IL, Douglas County, IL, Edgar County, IL, Ford County, IL, Grundy County, IL, Iroquois County, IL, Kankakee County, IL, LaSalle County, IL, Livingston County, IL, Logan County, IL, Macon County, IL, Marshall County, IL, McLean County, IL, Peoria County, IL, Piatt County, IL, Putnam County, IL, Stark County, IL, Tazewell County, IL, Vermilion County, IL, Woodford County, IL, Benton County, IN, Carroll County, IN, Fountain County, IN, Jasper County, IN, Montgomery County, IN, Newton County, IN, Tippecanoe County, IN, Vermillion County, IN, Warren County, IN, White County, IN
The radar
The Lincoln radar (KILX), 84 km from the middle of the area, began a volume at 19:33 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 watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Lincoln, IL (KILX), launched 12:00Z, 7.5 hours before the alert went out and 52 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
- 1168 m above ground
- 0-6 km bulk shear
- 68 kt
- 0-1 km storm-relative helicity
- 134 m²/s²
- 0-3 km storm-relative helicity
- 351 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.2
The text
As transmitted, in the capitals the NWS used until 2016.
104
ACUS11 KWNS 071933
SWOMCD
SPC MCD 071932
INZ000-ILZ000-072130-
MESOSCALE DISCUSSION 0698
NWS STORM PREDICTION CENTER NORMAN OK
0232 PM CDT SAT MAY 07 2011
AREAS AFFECTED...PARTS OF NRN/CNTRL ILLINOIS INTO NORTHWESTERN
INDIANA
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 071932Z - 072130Z
TRENDS ARE BEING MONITORED FOR THE DEVELOPMENT OF SEVERE STORMS THAT
PROBABLY WILL REQUIRE A WW LATE THIS AFTERNOON AND EVENING.
A SURFACE FRONTAL ZONE CONTINUES TO BECOME BETTER DEFINED ACROSS
PARTS OF NORTHERN ILLINOIS AND INDIANA...WITH SOUTHEASTWARD
DEVELOPMENT OF A LOW CENTER ALONG IT ONGOING ACROSS UPPER PORTIONS
OF THE MIDDLE MISSISSIPPI VALLEY INTO NORTHWESTERN ILLINOIS. UPPER
RIDGING IS BUILDING TO THE WEST...BUT ENHANCED MID-LEVEL FORCING FOR
ASCENT ASSOCIATED WITH A LOW AMPLITUDE SHORT WAVE IMPULSE STILL
APPEARS LIKELY TO OVERSPREAD THE FRONT...AND PORTIONS OF THE WARM
SECTOR TO THE IMMEDIATE SOUTHEAST OF THE LOW...ROUGHLY ALONG/BETWEEN
THE INTERSTATE 74 AND INTERSTATE 80 CORRIDORS...BETWEEN NOW AND
22-23Z.
INCREASING LIFT COUPLED WITH ONGOING WEAK TO MODERATE BOUNDARY LAYER
DESTABILIZATION PROBABLY WILL BE ACCOMPANIED BY VIGOROUS CONVECTIVE
DEVELOPMENT. NEAR INTERSECTING LOW-LEVEL THERMAL AND MOISTURE AXES
EMANATING FROM THE PLAINS /WHERE SURFACE TEMPS ARE APPROACHING 80F
AND DEW POINTS NEAR 60F/...MIXED LAYER CAPE APPEARS LIKELY TO REACH
1000 J/KG BY PEAK HEATING. IN THE PRESENCE OF STRONG SHEAR BENEATH
THE NORTHERN EDGE OF A 50+ KT 500 MB JET AXIS...ISOLATED SUPERCELL
DEVELOPMENT APPEARS POSSIBLE ...PERHAPS GROWING UPSCALE INTO A SMALL
CONVECTIVE CLUSTER CAPABLE OF PRODUCING DAMAGING WIND GUSTS...IN
ADDITION TO LARGE HAIL. TORNADIC POTENTIAL IS MORE UNCERTAIN...BUT
A TORNADO OR TWO MAY NOT BE OUT OF THE QUESTION...PARTICULARLY IN
RELATIVELY EARLY STAGES OF STORM DEVELOPMENT.
..KERR.. 05/07/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...IWX...IND...LOT...ILX...DVN...
LAT...LON 41748996 41318732 40748639 39908686 39688760 39658819
39888956 40458963 41059003 41748996SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 7, 2:59 PM CDT | Severe Thunderstorm Watch | SPC | Champaign, Clark, Coles, DeWitt, Douglas, Edgar and 18 more | 7 hr |
Nearby
Mesoscale Discussions in Illinois, 2011Mesoscale Discussions in Indiana, 2011Every mesoscale discussion in 2011
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.