Alert archive / Illinois / Tornado Watches in 2009
Tornado Watch 297
The Storm Prediction Center issued this tornado watch at May 13, 2009, 6:02 PM CDT for 32 counties in Illinois. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- May 13, 2009, 6:02 PM CDT (23:02 UTC)
- Expired
- May 13, 2009, 11:00 PM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 32 counties
Boone County, IL, Champaign County, IL, Cook County, IL, DeKalb County, IL, DeWitt County, IL, DuPage County, IL, Ford County, IL, Grundy County, IL, Iroquois County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Logan County, IL, Macon County, IL, Marshall County, IL, McHenry County, IL, McLean County, IL, Menard County, IL, Ogle County, IL, Peoria County, IL, Piatt County, IL, Sangamon County, IL, Stark County, IL, Tazewell County, IL, Vermilion County, IL, Will County, IL, Winnebago County, IL, Woodford County, IL
The radar
The Chicago radar (KLOT), 70 km from the middle of the area, began a volume at 23:02 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
- 50%
- One or more EF2 to EF5 tornadoes
- 30%
- Ten or more severe wind reports
- 40%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 50%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
9 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 13, 6:26 PM CDT | Severe Thunderstorm Warning | LOT | DeKalb, LaSalle, Lee, Ogle | 28 min |
| May 13, 9:19 PM CDT | Severe Thunderstorm Warning | LOT | Boone, Ogle, Winnebago | 56 min |
| May 13, 9:22 PM CDT | Flash Flood Warning | LOT | Boone, Ogle, Winnebago | 4 hr |
| May 13, 9:45 PM CDT | Severe Thunderstorm Warning | ILX | Marshall, Peoria, Stark, Woodford | 36 min |
| May 13, 9:59 PM CDT | Severe Thunderstorm Warning | LOT | Boone, DeKalb, Kane, McHenry, Ogle, Winnebago | 61 min |
| May 13, 10:11 PM CDT | Severe Thunderstorm Warning | ILX | Cass, Menard, Morgan, Sangamon, Scott | 49 min |
| May 13, 10:35 PM CDT | Severe Thunderstorm Warning | LOT | Cook, Grundy, Will | 40 min |
| May 13, 10:41 PM CDT | Severe Thunderstorm Warning | ILX | Christian, DeWitt, Logan, Macon, Menard, Morgan and 1 more | 49 min |
| May 13, 10:55 PM CDT | Flash Flood Warning | ILX | Christian, Morgan, Sangamon | 6 hr |
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, 11.0 hours before the alert went out and 131 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
- 556 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 332 m²/s²
- 0-3 km storm-relative helicity
- 344 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 |
|---|---|---|---|---|
| May 13, 9:27 AM CDT | Mesoscale Discussion | SPC | Adams, Bond, Brown, Calhoun, Cass, Champaign and 54 more | 63 min |
| May 13, 1:15 PM CDT | Mesoscale Discussion | SPC | Bond, Clinton, Franklin, Jackson, Jefferson, Macoupin and 7 more | 30 min |
| May 13, 1:52 PM CDT | Mesoscale Discussion | SPC | Adams, Brown, Calhoun, Greene, Hancock, Jersey and 3 more | 23 min |
| May 13, 2:39 PM CDT | Tornado Watch | SPC | Adams, Brown, Bureau, Calhoun, Cass, Fulton and 16 more | 7 hr |
| May 13, 3:00 PM CDT | Tornado Watch | SPC | Bond, Clark, Clay, Clinton, Crawford, Cumberland and 24 more | 5 hr |
| May 13, 5:47 PM CDT | Mesoscale Discussion | SPC | Adams, Boone, Brown, Bureau, Carroll, Cass and 50 more | 88 min |
| May 13, 6:05 PM CDT | Mesoscale Discussion | SPC | Clark, Clay, Crawford, Edwards, Effingham, Franklin and 17 more | 85 min |
Nearby
Tornado Watches in Illinois, 2009Every tornado watch 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.