Alert archive / Illinois / Mesoscale Discussions in 2009
Mesoscale Discussion 1921
The Storm Prediction Center issued this mesoscale discussion at Aug 19, 2009, 3:19 PM CDT for 28 counties in Illinois; 14 counties in Indiana. It was in force for 86 min.
The area
The outline as issued.
The facts
- Issued
- Aug 19, 2009, 3:19 PM CDT (20:19 UTC)
- Expired
- Aug 19, 2009, 4:45 PM CDT
- In force
- 86 min
- Issued by
- the Storm Prediction Center
All 42 counties
Champaign County, IL, Christian County, IL, Clark County, IL, Coles County, IL, Cumberland 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, Montgomery County, IL, Moultrie County, IL, Peoria County, IL, Piatt County, IL, Putnam County, IL, Shelby County, IL, Stark County, IL, Tazewell County, IL, Vermilion County, IL, Woodford County, IL, Benton County, IN, Clay County, IN, Fountain County, IN, Jasper County, IN, Montgomery County, IN, Newton County, IN, Owen County, IN, Parke County, IN, Putnam County, IN, Tippecanoe County, IN, Vermillion County, IN, Vigo County, IN, Warren County, IN, White County, IN
The radar
The Lincoln radar (KILX), 80 km from the middle of the area, began a volume at 20:23 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, 8.3 hours before the alert went out and 19 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
- 272 J/kg
- Mixed-layer CIN
- -24 J/kg
- Mixed-layer LCL
- 766 m above ground
- 0-6 km bulk shear
- 31 kt
- 0-1 km storm-relative helicity
- 95 m²/s²
- 0-3 km storm-relative helicity
- 137 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.8
The text
As transmitted, in the capitals the NWS used until 2016.
000
ACUS11 KWNS 192019
SWOMCD
SPC MCD 192019
INZ000-ILZ000-192145-
MESOSCALE DISCUSSION 1921
NWS STORM PREDICTION CENTER NORMAN OK
0319 PM CDT WED AUG 19 2009
AREAS AFFECTED...CENTRAL AND INTO NRN IL
CONCERNING...TORNADO WATCH 713...
VALID 192019Z - 192145Z
THE SEVERE WEATHER THREAT FOR TORNADO WATCH 713 CONTINUES.
SEVERE/TORNADO THREAT CONTINUES WITH A BAND OF INTENSE STORMS
CROSSING CENTRAL IL.
LATEST RADAR IMAGERY SHOWS A COMPLEX LINE OF STRONG TO LOCALLY
SEVERE STORMS MOVING ENEWD ACROSS CENTRAL IL...INVOF A SURFACE WARM
FRONT LYING NW-SE ACROSS THIS AREA. OBJECTIVE ANALYSES REVEAL
AROUND 2000 J/KG MIXED-LAYER CAPE NEAR AND S OF THE WARM
FRONT...SUPPORTING STORM CONTINUATION/REDEVELOPMENT OVER THE NEXT
COUPLE OF HOURS. WITH MID-LEVEL SWLYS NEAR 50 KT NOSING INTO/ACROSS
THIS AREA ATOP LOW-LEVEL SLYS/SELYS...SHEAR REMAINS SUPPORTIVE OF
SUPERCELLS. GREATEST TORNADO THREAT CONTINUES NEAR AND TO THE
IMMEDIATE COOL SIDE OF THE WARM FRONT -- I.E. WITH STORMS ALONG THE
SRN EXTENT OF THE CONVECTIVE LINE -- WHERE MOST FAVORABLE
JUXTAPOSITION OF FAVORABLE LOW-LEVEL THERMODYNAMICS AND BACKED
LOW-LEVEL FLOW/MAXIMIZED LOW-LEVEL SHEAR IS EVIDENT.
..GOSS.. 08/19/2009
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...IWX...IND...LOT...ILX...LSX...DVN...
LAT...LON 40978664 39308672 39108796 39218949 39358978 40298949
41169000 41648883 40978664SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 19, 11:51 AM CDT | Mesoscale Discussion | SPC | Adams, Bond, Brown, Bureau, Calhoun, Cass and 45 more | 114 min |
| Aug 19, 12:49 PM CDT | Tornado Watch | SPC | Adams, Brown, Bureau, Cass, Champaign, Christian and 52 more | 6 hr |
| Aug 19, 3:05 PM CDT | Tornado Watch | SPC | Champaign, Christian, Coles, Douglas, Edgar, Moultrie and 2 more | 2 hr |
| Aug 19, 4:49 PM CDT | Tornado Watch | SPC | Bureau, Carroll, Henry, Jo Daviess, Mercer, Putnam and 3 more | 5 hr |
| Aug 19, 5:11 PM CDT | Tornado Watch | SPC | Clark, Clay, Crawford, Cumberland, Effingham, Jasper and 2 more | 5 hr |
| Aug 19, 4:36 PM CDT | Mesoscale Discussion | SPC | Adams, Allen, Benton, Blackford, Boone, Carroll and 35 more | 84 min |
Nearby
Mesoscale Discussions in Illinois, 2009Mesoscale Discussions in Indiana, 2009Every mesoscale discussion in 2009
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.