Alert archive / Illinois / Mesoscale Discussions in 2008
Mesoscale Discussion 1721
The Storm Prediction Center issued this mesoscale discussion at Jul 7, 2008, 10:21 PM CDT for 10 counties in Illinois. It was in force for 84 min.
The area
The outline as issued.
The facts
- Issued
- Jul 7, 2008, 10:21 PM CDT (03:21 UTC)
- Expired
- Jul 7, 2008, 11:45 PM CDT
- In force
- 84 min
- Issued by
- the Storm Prediction Center
Counties Boone County, IL, Bureau County, IL, DeKalb County, IL, DuPage County, IL, Kane County, IL, Kendall County, IL, LaSalle County, IL, Lee County, IL, McHenry County, IL, Ogle County, IL
The radar
The Chicago radar (KLOT), 62 km from the middle of the area, began a volume at 03:22 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
Davenport, (KDVN), launched 00:00Z, 3.4 hours before the alert went out and 146 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
- 3226 J/kg
- Mixed-layer CIN
- -23 J/kg
- Mixed-layer LCL
- 1042 m above ground
- 0-6 km bulk shear
- 28 kt
- 0-1 km storm-relative helicity
- 171 m²/s²
- 0-3 km storm-relative helicity
- 274 m²/s²
- Significant tornado parameter
- 2.7
- Supercell composite
- 16.8
The text
As transmitted, in the capitals the NWS used until 2016.
000 ACUS11 KWNS 080321 SWOMCD SPC MCD 080321 ILZ000-080445- MESOSCALE DISCUSSION 1721 NWS STORM PREDICTION CENTER NORMAN OK 1021 PM CDT MON JUL 07 2008 AREAS AFFECTED...NE IL...INCLUDING CHICAGO CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 080321Z - 080445Z LINE OF TSTMS...SPANNING AN AREA FROM SE WI ACROSS NW IL INTO SE IA...HAS BECOME ORIENTED MORE SW-NE OVER THE PAST COUPLE OF HOURS. PERUSAL OF VWP/PROFILES SUGGESTS THE GEOMETRY OF THE LINE WITH RESPECT TO THE LOW-LEVEL FLOW HAS MADE FOR AN UNFAVORABLE SITUATION FOR SUSTAINED BOWS. IN FACT...SITUATION HAS NEARLY BECOME ANAFRONTAL ACROSS EC IA. AS A RESULT...AS THE LINE PROGRESSES INTO THE ROCKFORD AND LA SALLE TOWARD THE CHICAGO METRO AREA THROUGH 04-06Z...THE SVR THREAT LOOKS MINIMAL...SAVE FOR AN ISOLD DMGG WIND GUST OR TWO. THUS...A NEW WW DOWNSTREAM IS UNLIKELY. ..RACY.. 07/08/2008 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...LOT...DVN... 41938956 42398893 42398812 42098766 41758768 41418821 41238923 41348994
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 7, 7:30 PM CDT | Mesoscale Discussion | SPC | Carroll, Jo Daviess | 30 min |
| Jul 7, 7:40 PM CDT | Severe Thunderstorm Watch | SPC | Carroll, Jo Daviess, Rock Island, Stephenson, Whiteside | 4 hr |
| Jul 7, 8:32 PM CDT | Mesoscale Discussion | SPC | Boone, Carroll, DeKalb, Jo Daviess, Kane, Lee and 5 more | 88 min |
| Jul 8, 1:15 AM CDT | Mesoscale Discussion | SPC | Ford, Fulton, Hancock, Henderson, Knox, Livingston and 10 more | 3 hr |
| Jul 8, 1:27 PM CDT | Mesoscale Discussion | SPC | Adams, Bond, Brown, Calhoun, Cass, Champaign and 35 more | 93 min |
| Jul 8, 1:54 PM CDT | Severe Thunderstorm Watch | SPC | Adams, Bond, Brown, Calhoun, Cass, Champaign and 34 more | 7 hr |
| Jul 8, 4:22 PM CDT | Mesoscale Discussion | SPC | Bond, Calhoun, Champaign, Christian, Clark, Clay and 25 more | 53 min |
| Jul 8, 6:02 PM CDT | Mesoscale Discussion | SPC | Bond, Calhoun, Champaign, Christian, Clark, Clay and 25 more | 58 min |
Nearby
Mesoscale Discussions in Illinois, 2008Every mesoscale discussion in 2008
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.