Alert archive / Illinois / Tornado Watches in 2015
Tornado Watch 535
The Storm Prediction Center issued this tornado watch at Nov 11, 2015, 3:20 PM CST for 29 counties in Illinois; 21 counties in Iowa; 14 counties in Missouri. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Nov 11, 2015, 3:20 PM CST (21:20 UTC)
- Expired
- Nov 11, 2015, 9:00 PM CST
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1 in
- Strongest gust expected
- 60 kt
All 64 counties
Benton County, IA, Buchanan County, IA, Cedar County, IA, Clinton County, IA, Delaware County, IA, Des Moines County, IA, Dubuque County, IA, Henry County, IA, Iowa County, IA, Jackson County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Lee County, IA, Linn County, IA, Louisa County, IA, Muscatine County, IA, Scott County, IA, Van Buren County, IA, Washington County, IA, Adams County, IL, Brown County, IL, Bureau County, IL, Carroll County, IL, Cass County, IL, Fulton County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, Jo Daviess County, IL, Knox County, IL, Marshall County, IL, Mason County, IL, McDonough County, IL, McLean County, IL, Mercer County, IL, Morgan County, IL, Peoria County, IL, Pike County, IL, Putnam County, IL, Rock Island County, IL, Schuyler County, IL, Scott County, IL, Stark County, IL, Stephenson County, IL, Tazewell County, IL, Warren County, IL, Whiteside County, IL, Woodford County, IL, Audrain County, MO, Boone County, MO, Callaway County, MO, Clark County, MO, Cole County, MO, Knox County, MO, Lewis County, MO, Marion County, MO, Moniteau County, MO, Monroe County, MO, Pike County, MO, Ralls County, MO, Scotland County, MO, Shelby County, MO
The radar
The Quad Cities radar (KDVN), 109 km from the middle of the area, began a volume at 21:23 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.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 40%
- One or more EF2 to EF5 tornadoes
- 20%
- Ten or more severe wind reports
- 50%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 20%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
18 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Nov 11, 3:55 PM CST | Severe Thunderstorm Warning | DVN | Jefferson, Keokuk, Van Buren, Washington | 65 min |
| Nov 11, 3:59 PM CST | Severe Thunderstorm Warning | LSX | Knox, Lewis, Marion, Monroe, Shelby | 61 min |
| Nov 11, 4:16 PM CST | Severe Thunderstorm Warning | DVN | Benton, Iowa | 59 min |
| Nov 11, 4:17 PM CST | Tornado Warning | DVN | Iowa, Keokuk | 43 min |
| Nov 11, 4:44 PM CST | Severe Thunderstorm Warning | DVN | Henry, Jefferson, Johnson, Linn, Louisa, Washington | 61 min |
| Nov 11, 4:52 PM CST | Severe Thunderstorm Warning | DVN | Hancock | 53 min |
| Nov 11, 4:52 PM CST | Severe Thunderstorm Warning | LSX | Adams | 38 min |
| Nov 11, 5:05 PM CST | Severe Thunderstorm Warning | LSX | Adams, Pike | 40 min |
| Nov 11, 5:07 PM CST | Tornado Warning | DVN | Johnson, Linn | 18 min |
| Nov 11, 5:20 PM CST | Severe Thunderstorm Warning | DVN | Mercer, Rock Island | 55 min |
| Nov 11, 5:28 PM CST | Severe Thunderstorm Warning | DVN | Hancock, Henderson, McDonough, Mercer, Warren | 62 min |
| Nov 11, 5:47 PM CST | Tornado Warning | DVN | Cedar, Jones | 14 min |
| Nov 11, 5:55 PM CST | Severe Thunderstorm Warning | DVN | Delaware, Dubuque, Jackson, Jones | 49 min |
| Nov 11, 6:01 PM CST | Severe Thunderstorm Warning | ILX | Fulton, Knox, Peoria, Stark | 59 min |
| Nov 11, 6:54 PM CST | Severe Thunderstorm Warning | ILX | Fulton, Knox, Marshall, Mason, Peoria, Stark and 2 more | 66 min |
| Nov 11, 6:56 PM CST | Severe Thunderstorm Warning | DVN | Bureau, Henry, Putnam, Whiteside | 64 min |
| Nov 11, 6:58 PM CST | Severe Thunderstorm Warning | DVN | Carroll, Jo Daviess, Stephenson, Whiteside | 52 min |
| Nov 11, 7:45 PM CST | Severe Thunderstorm Warning | ILX | McLean, Marshall, Tazewell, Woodford | 45 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Davenport, (KDVN), launched 12:00Z, 9.3 hours before the alert went out and 115 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
- 1035 m above ground
- 0-6 km bulk shear
- 50 kt
- 0-1 km storm-relative helicity
- 101 m²/s²
- 0-3 km storm-relative helicity
- 238 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Nov 11, 2:24 PM CST | Mesoscale Discussion | SPC | Adams, Brown, Cass, Fulton, Greene, Hancock and 12 more | 2 hr |
| Nov 11, 5:46 PM CST | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, DeKalb, DeWitt, Ford and 14 more | 59 min |
| Nov 11, 10:17 AM CST | Mesoscale Discussion | SPC | Adair, Adams, Appanoose, Audubon, Benton, Black Hawk and 54 more | 118 min |
| Nov 11, 11:25 AM CST | Tornado Watch | SPC | Adair, Adams, Appanoose, Audubon, Black Hawk, Boone and 41 more | 6 hr |
| Nov 11, 12:38 PM CST | Mesoscale Discussion | SPC | Crawford, Harrison | 67 min |
| Nov 11, 1:42 PM CST | Mesoscale Discussion | SPC | Adair, Adams, Appanoose, Audubon, Boone, Carroll and 24 more | 93 min |
| Nov 11, 4:59 PM CST | Mesoscale Discussion | SPC | Allamakee, Clayton | 91 min |
Nearby
Tornado Watches in Illinois, 2015Tornado Watches in Iowa, 2015Tornado Watches in Missouri, 2015Every tornado watch in 2015
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.