Alert archive / Illinois / Mesoscale Discussions in 2012

Mesoscale Discussion 680

May 3, 201228 counties in Illinois

The Storm Prediction Center issued this mesoscale discussion at May 3, 2012, 3:53 PM CDT for 28 counties in Illinois. It was in force for 37 min.

The area

The outline as issued.

The facts

Issued
May 3, 2012, 3:53 PM CDT (20:53 UTC)
Expired
May 3, 2012, 4:30 PM CDT
In force
37 min
Issued by
the Storm Prediction Center
Chance of a watch
95%
All 28 counties

Brown County, IL, Bureau County, IL, Cass County, IL, DeWitt County, IL, Fulton County, IL, Greene County, IL, Hancock County, IL, Henry County, IL, Knox County, IL, LaSalle County, IL, Livingston County, IL, Logan County, IL, Macon County, IL, Marshall County, IL, Mason County, IL, McDonough County, IL, McLean County, IL, Menard County, IL, Morgan County, IL, Peoria County, IL, Putnam County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Stark County, IL, Tazewell County, IL, Warren County, IL, Woodford County, IL

The radar

The Lincoln radar (KILX), 64 km from the middle of the area, began a volume at 20:51 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, 8.9 hours before the alert went out and 124 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.

Skew-T log-pSkew-T log-p diagram, Lincoln, IL at 12:00Z on 2012-05-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1717 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lincoln, IL at 12:00Z on 2012-05-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 122 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
1717 J/kg
Mixed-layer CIN
-76 J/kg
Mixed-layer LCL
775 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
122 m²/s²
0-3 km storm-relative helicity
49 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

814 
ACUS11 KWNS 032054
SWOMCD
SPC MCD 032053
ILZ000-IAZ000-032130-

MESOSCALE DISCUSSION 0680
NWS STORM PREDICTION CENTER NORMAN OK
0353 PM CDT THU MAY 03 2012

AREAS AFFECTED...CNTRL IL

CONCERNING...SEVERE POTENTIAL...WATCH NEEDED SOON

VALID 032053Z - 032130Z

PROBABILITY OF WATCH ISSUANCE...95 PERCENT

SUMMARY...TORNADO WATCH WILL BE ISSUED SHORTLY.

DISCUSSION...ENVIRONMENTAL CONDITIONS HAVE BECOME FAVORABLE FOR
SEVERE STORMS AND A WATCH ISSUANCE WILL BE COORDINATED BETWEEN THE
SPC AND THE AFFECTED LOCAL NATIONAL WEATHER SERVICE OFFICES SHORTLY.

..DARROW.. 05/03/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...LOT...ILX...LSX...DVN...

LAT...LON   40339146 41618980 41218810 39708875 39219055 40339146

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 3, 1:07 PM CDTSevere Thunderstorm WatchSPCBoone, Cook, DeKalb, DuPage, Kane, Kendall and 5 more6 hr
May 3, 2:53 PM CDTMesoscale DiscussionSPCBoone, Cook, DeKalb, DuPage, Kane, Lake and 3 more67 min
May 3, 4:20 PM CDTTornado WatchSPCBureau, Cass, Champaign, DeWitt, Ford, Fulton and 26 more8 hr
May 3, 6:22 PM CDTMesoscale DiscussionSPCCook, DeKalb, DuPage, Kane, Kendall, Lake and 1 more23 min
May 3, 6:41 PM CDTSevere Thunderstorm WatchSPCBoone, Cook, DeKalb, DuPage, Ford, Grundy and 12 more5 hr
May 3, 6:42 PM CDTMesoscale DiscussionSPCAdams, Brown, Cass, DeWitt, Fulton, Greene and 17 more63 min

Nearby

Mesoscale 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.