Alert archive / Illinois / Tornado Watches in 2019

Tornado Watch 665

September 27, 201929 counties in Illinois; 12 counties in Iowa; 6 counties in Missouri

The Storm Prediction Center issued this tornado watch at Sep 27, 2019, 4:00 PM CDT for 29 counties in Illinois; 12 counties in Iowa; 6 counties in Missouri. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Sep 27, 2019, 4:00 PM CDT (21:00 UTC)
Expired
Sep 27, 2019, 11:00 PM CDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
3 in
Strongest gust expected
65 kt
All 47 counties

Cedar County, IA, Clinton County, IA, Des Moines County, IA, Henry County, IA, Jefferson County, IA, Johnson County, IA, Lee 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, Cass County, IL, DeWitt County, IL, Ford County, IL, Fulton County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, Knox County, IL, LaSalle County, IL, Livingston County, IL, Logan County, IL, Marshall County, IL, Mason County, IL, McDonough County, IL, McLean County, IL, Menard County, IL, Mercer County, IL, Peoria County, IL, Putnam County, IL, Rock Island County, IL, Schuyler County, IL, Stark County, IL, Tazewell County, IL, Warren County, IL, Whiteside County, IL, Woodford County, IL, Clark County, MO, Knox County, MO, Lewis County, MO, Marion County, MO, Scotland County, MO, Shelby County, MO

The radar

The Quad Cities radar (KDVN), 63 km from the middle of the area, began a volume at 21:03 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
40%
Ten or more severe wind reports
50%
One or more gusts of 65 knots or more
50%
Ten or more severe hail reports
60%
One or more hailstones of 2 inches or more
60%
Six or more combined severe hail and wind reports
90%

Warnings issued inside it

46 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Sep 27, 4:05 PM CDTSevere Thunderstorm WarningILXMarshall, Tazewell, Woodford25 min
Sep 27, 5:10 PM CDTSevere Thunderstorm WarningDVNHancock, Henderson26 min
Sep 27, 5:34 PM CDTSevere Thunderstorm WarningDVNHenderson, Warren41 min
Sep 27, 5:37 PM CDTSevere Thunderstorm WarningDVNBureau53 min
Sep 27, 5:48 PM CDTSevere Thunderstorm WarningDVNClark, Scotland42 min
Sep 27, 5:51 PM CDTSevere Thunderstorm WarningDVNHancock39 min
Sep 27, 6:07 PM CDTSevere Thunderstorm WarningDVNBureau23 min
Sep 27, 6:12 PM CDTSevere Thunderstorm WarningDVNWarren33 min
Sep 27, 6:12 PM CDTSevere Thunderstorm WarningLSXKnox48 min
Sep 27, 6:15 PM CDTSevere Thunderstorm WarningDVNLee45 min
Sep 27, 6:19 PM CDTSevere Thunderstorm WarningILXFulton, Knox41 min
Sep 27, 6:20 PM CDTSevere Thunderstorm WarningDVNHenderson, Mercer, Warren40 min
Sep 27, 6:30 PM CDTTornado WarningDVNHancock25 min
Sep 27, 6:30 PM CDTSevere Thunderstorm WarningLOTLaSalle45 min
Sep 27, 6:48 PM CDTSevere Thunderstorm WarningDVNHancock42 min
Sep 27, 6:52 PM CDTSevere Thunderstorm WarningLSXKnox, Lewis53 min
Sep 27, 6:53 PM CDTSevere Thunderstorm WarningDVNHancock52 min
Sep 27, 6:55 PM CDTSevere Thunderstorm WarningILXKnox, Peoria, Stark50 min
Sep 27, 7:00 PM CDTTornado WarningLSXKnox, Lewis45 min
Sep 27, 7:01 PM CDTTornado WarningILXKnox, Peoria29 min
Sep 27, 7:03 PM CDTFlash Flood WarningDVNBureau, Henry, Putnam6 hr
Sep 27, 7:06 PM CDTSevere Thunderstorm WarningLSXKnox39 min
Sep 27, 7:09 PM CDTSevere Thunderstorm WarningILXKnox, Stark51 min
Sep 27, 7:16 PM CDTFlash Flood WarningILXKnox, Marshall, Peoria, Stark6 hr
Sep 27, 7:24 PM CDTSevere Thunderstorm WarningDVNHancock, McDonough, Warren51 min
Sep 27, 7:34 PM CDTTornado WarningLSXAdams41 min
Sep 27, 7:37 PM CDTSevere Thunderstorm WarningILXMarshall, Peoria, Woodford38 min
Sep 27, 7:37 PM CDTFlash Flood WarningLOTGrundy, Kendall, LaSalle6 hr
Sep 27, 7:53 PM CDTSevere Thunderstorm WarningILXFulton52 min
Sep 27, 7:58 PM CDTFlash Flood WarningILXFulton, Knox6 hr
Sep 27, 8:00 PM CDTSevere Thunderstorm WarningLOTGrundy, Kendall, LaSalle30 min
Sep 27, 8:07 PM CDTTornado WarningLSXAdams53 min
Sep 27, 8:11 PM CDTSevere Thunderstorm WarningILXMarshall19 min
Sep 27, 8:14 PM CDTSevere Thunderstorm WarningLSXKnox46 min
Sep 27, 8:19 PM CDTFlash Flood WarningDVNHancock, McDonough6 hr
Sep 27, 8:26 PM CDTTornado WarningILXFulton, Peoria, Tazewell19 min
Sep 27, 8:36 PM CDTFlash Flood WarningILXPeoria, Tazewell, Woodford6 hr
Sep 27, 8:39 PM CDTSevere Thunderstorm WarningILXPeoria, Tazewell, Woodford36 min
Sep 27, 8:41 PM CDTSevere Thunderstorm WarningDVNHancock16 min
Sep 27, 8:45 PM CDTSevere Thunderstorm WarningILXSchuyler32 min
Sep 27, 8:51 PM CDTSevere Thunderstorm WarningLSXLewis54 min
Sep 27, 8:53 PM CDTSevere Thunderstorm WarningILXFulton, Peoria, Tazewell37 min
Sep 27, 8:59 PM CDTFlash Flood WarningLSXKnox, Lewis8 hr
Sep 27, 9:02 PM CDTFlash Flood WarningLOTGrundy, LaSalle, Livingston6 hr
Sep 27, 9:04 PM CDTFlash Flood WarningDVNHenderson, Warren6 hr
Sep 27, 10:14 PM CDTSevere Thunderstorm WarningLSXAdams, Brown, Pike46 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, 9.0 hours before the alert went out and 65 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, Davenport, at 12:00Z on 2019-09-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Davenport, at 12:00Z on 2019-09-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 346 square meters per square second.19395878Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1100 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
346 m²/s²
0-3 km storm-relative helicity
321 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 27, 3:01 PM CDTMesoscale DiscussionSPCBureau, Cass, Fulton, Hancock, Henderson, Henry and 18 more119 min
Sep 27, 3:49 PM CDTSevere Thunderstorm WatchSPCCarroll, Jo Daviess, Stephenson7 hr
Sep 27, 6:21 PM CDTMesoscale DiscussionSPCAdams, Brown, Bureau, Cass, DeKalb, DeWitt and 30 more114 min
Sep 27, 5:37 PM CDTMesoscale DiscussionSPCAppanoose, Wayne2 hr
Sep 27, 6:16 PM CDTSevere Thunderstorm WatchSPCAdair, Andrew, Buchanan, Caldwell, Carroll, Cass and 25 more8 hr

Nearby

Tornado Watches in Illinois, 2019Tornado Watches in Iowa, 2019Tornado Watches in Missouri, 2019Every tornado watch in 2019

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.