Alert archive / Illinois / Tornado Watches in 2015
Tornado Watch 561
The Storm Prediction Center issued this tornado watch at Dec 23, 2015, 1:55 PM CST for 30 counties in Illinois; 18 counties in Iowa; 21 counties in Missouri. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Dec 23, 2015, 1:55 PM CST (19:55 UTC)
- Expired
- Dec 23, 2015, 5:58 PM CST
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 69 counties
Appanoose County, IA, Cedar County, IA, Clinton County, IA, Davis County, IA, Des Moines County, IA, Henry County, IA, Jefferson County, IA, Johnson County, IA, Keokuk County, IA, Lee County, IA, Louisa County, IA, Mahaska County, IA, Monroe County, IA, Muscatine County, IA, Scott County, IA, Van Buren County, IA, Wapello County, IA, Washington County, IA, Adams County, IL, Brown County, IL, Bureau County, IL, Calhoun County, IL, Cass County, IL, Fulton County, IL, Greene County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, Jersey County, IL, Knox County, IL, Macoupin County, IL, Madison County, IL, Marshall County, IL, Mason County, IL, McDonough County, IL, Mercer County, IL, Monroe County, IL, Morgan County, IL, Peoria County, IL, Pike County, IL, Putnam County, IL, Rock Island County, IL, Saint Clair County, IL, Schuyler County, IL, Scott County, IL, Stark County, IL, Warren County, IL, Whiteside County, IL, Audrain County, MO, Callaway County, MO, City of Saint Louis, MO, Clark County, MO, Franklin County, MO, Gasconade County, MO, Jefferson County, MO, Knox County, MO, Lewis County, MO, Lincoln County, MO, Marion County, MO, Monroe County, MO, Montgomery County, MO, Osage County, MO, Pike County, MO, Ralls County, MO, Saint Charles County, MO, Saint Louis County, MO, Scotland County, MO, Shelby County, MO, Warren County, MO
The radar
The Quad Cities radar (KDVN), 139 km from the middle of the area, began a volume at 19:57 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
- 20%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 40%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
17 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 23, 2:46 PM CST | Severe Thunderstorm Warning | LSX | Marion, Monroe, Ralls | 44 min |
| Dec 23, 2:53 PM CST | Severe Thunderstorm Warning | DVN | Hancock | 52 min |
| Dec 23, 3:09 PM CST | Severe Thunderstorm Warning | LSX | Adams | 51 min |
| Dec 23, 3:13 PM CST | Severe Thunderstorm Warning | LSX | Pike | 16 min |
| Dec 23, 3:25 PM CST | Severe Thunderstorm Warning | DVN | Henry, Jefferson, Washington | 35 min |
| Dec 23, 3:35 PM CST | Severe Thunderstorm Warning | DVN | Hancock, Henderson | 40 min |
| Dec 23, 3:40 PM CST | Severe Thunderstorm Warning | LSX | Calhoun, Pike | 50 min |
| Dec 23, 3:44 PM CST | Severe Thunderstorm Warning | ILX | Schuyler | 46 min |
| Dec 23, 3:45 PM CST | Severe Thunderstorm Warning | LSX | Pike | 45 min |
| Dec 23, 3:51 PM CST | Tornado Warning | LSX | Pike | 24 min |
| Dec 23, 3:52 PM CST | Severe Thunderstorm Warning | LSX | Adams, Brown | 38 min |
| Dec 23, 4:11 PM CST | Tornado Warning | LSX | Pike | 13 min |
| Dec 23, 4:16 PM CST | Tornado Warning | ILX | Cass, Morgan, Scott | 29 min |
| Dec 23, 4:19 PM CST | Tornado Warning | DVN | McDonough, Warren | 26 min |
| Dec 23, 4:28 PM CST | Severe Thunderstorm Warning | ILX | Fulton, Schuyler | 31 min |
| Dec 23, 4:45 PM CST | Tornado Warning | DVN | Rock Island | 30 min |
| Dec 23, 5:08 PM CST | Tornado Warning | ILX | Knox | 20 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, 7.9 hours before the alert went out and 142 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
- 1366 m above ground
- 0-6 km bulk shear
- 74 kt
- 0-1 km storm-relative helicity
- -11 m²/s²
- 0-3 km storm-relative helicity
- 229 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
896
WWUS20 KWNS 231953
SEL1
SPC WW 231953
IAZ000-ILZ000-MOZ000-240200-
URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 561
NWS STORM PREDICTION CENTER NORMAN OK
155 PM CST WED DEC 23 2015
THE NWS STORM PREDICTION CENTER HAS ISSUED A
* TORNADO WATCH FOR PORTIONS OF
SOUTHEAST IOWA
WESTERN ILLINOIS
NORTHEAST MISSOURI
* EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 155 PM
UNTIL 800 PM CST.
* PRIMARY THREATS INCLUDE...
A FEW TORNADOES POSSIBLE
SCATTERED LARGE HAIL AND ISOLATED VERY LARGE HAIL EVENTS TO 2
INCHES IN DIAMETER POSSIBLE
ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE
SUMMARY...ISOLATED TO SCATTERED STORMS SHOULD FORM FROM THE
MISSOURI/IOWA BORDER AREA SOUTH INTO EAST-CENTRAL MISSOURI.
ENVIRONMENT WILL FAVOR A FEW SUPERCELLS EVOLVING NORTHEAST WITH ALL
HAZARDS POSSIBLE.
THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 65 STATUTE
MILES EAST AND WEST OF A LINE FROM 45 MILES NORTHWEST OF MOLINE
ILLINOIS TO 40 MILES SOUTHWEST OF SAINT LOUIS MISSOURI. FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU1).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 558...WW 559...WW 560...
AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
400. MEAN STORM MOTION VECTOR 21040.
...GRAMSSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 23, 6:13 AM CST | Mesoscale Discussion | SPC | Alexander, Bond, Clinton, Franklin, Gallatin, Hamilton and 17 more | 2 hr |
| Dec 23, 9:05 AM CST | Mesoscale Discussion | SPC | Alexander, Clay, Edwards, Franklin, Gallatin, Hamilton and 20 more | 85 min |
| Dec 23, 9:13 AM CST | Tornado Watch | SPC | Alexander, Bond, Champaign, Christian, Clark, Clay and 38 more | 8 hr |
| Dec 23, 9:41 AM CST | Mesoscale Discussion | SPC | Cook, DuPage, Ford, Grundy, Iroquois, Kane and 5 more | 2 hr |
| Dec 23, 10:29 AM CST | Mesoscale Discussion | SPC | Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 15 more | 91 min |
| Dec 23, 12:06 PM CST | Mesoscale Discussion | SPC | Clay, Crawford, Edwards, Gallatin, Hamilton, Hardin and 7 more | 84 min |
| Dec 23, 12:42 PM CST | Mesoscale Discussion | SPC | Adams, Brown, Bureau, Calhoun, Cass, Fulton and 25 more | 2 hr |
| Dec 23, 3:24 PM CST | Mesoscale Discussion | SPC | Adams, Brown, Bureau, Calhoun, Cass, Fulton and 26 more | 96 min |
| Dec 23, 2:49 PM CST | Mesoscale Discussion | SPC | Pemiscot | 86 min |
Nearby
Tornado Watches in Illinois, 2015Tornado Watches in Missouri, 2015Tornado Watches in Iowa, 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.