Alert archive / Illinois / Tornado Watches in 2015
Tornado Watch 46
The Storm Prediction Center issued this tornado watch at Apr 9, 2015, 4:40 PM CDT for 14 counties in Illinois; 14 counties in Missouri. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 9, 2015, 4:40 PM CDT (21:40 UTC)
- Expired
- Apr 9, 2015, 10:44 PM CDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2.5 in
- Strongest gust expected
- 60 kt
All 28 counties
Bond County, IL, Calhoun County, IL, Clinton County, IL, Fayette County, IL, Greene County, IL, Jersey County, IL, Macoupin County, IL, Madison County, IL, Marion County, IL, Monroe County, IL, Montgomery County, IL, Randolph County, IL, Saint Clair County, IL, Washington County, IL, City of Saint Louis, MO, Crawford County, MO, Franklin County, MO, Iron County, MO, Jefferson County, MO, Lincoln County, MO, Madison County, MO, Reynolds County, MO, Saint Charles County, MO, Saint Francois County, MO, Saint Louis County, MO, Sainte Genevieve County, MO, Warren County, MO, Washington County, MO
The radar
The St Louis radar (KLSX), 23 km from the middle of the area, began a volume at 21:41 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
- 60%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 60%
- One or more hailstones of 2 inches or more
- 40%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
21 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 9, 5:07 PM CDT | Severe Thunderstorm Warning | LSX | Callaway, Lincoln, Montgomery, Warren | 38 min |
| Apr 9, 5:19 PM CDT | Severe Thunderstorm Warning | LSX | Audrain, Lincoln, Pike, Ralls | 41 min |
| Apr 9, 5:42 PM CDT | Severe Thunderstorm Warning | LSX | Lincoln, Saint Charles, Warren | 25 min |
| Apr 9, 5:43 PM CDT | Severe Thunderstorm Warning | LSX | Calhoun, Greene, Pike | 32 min |
| Apr 9, 5:49 PM CDT | Tornado Warning | LSX | Lincoln, Saint Charles | 26 min |
| Apr 9, 6:04 PM CDT | Severe Thunderstorm Warning | LSX | Calhoun, Greene, Jersey, Madison | 41 min |
| Apr 9, 6:17 PM CDT | Severe Thunderstorm Warning | LSX | Crawford, Franklin, Jefferson, Saint Francois, Washington | 58 min |
| Apr 9, 6:35 PM CDT | Severe Thunderstorm Warning | LSX | Greene, Jersey, Macoupin, Madison | 55 min |
| Apr 9, 6:55 PM CDT | Severe Thunderstorm Warning | LSX | Jersey | 35 min |
| Apr 9, 7:04 PM CDT | Tornado Warning | LSX | Macoupin, Montgomery | 26 min |
| Apr 9, 7:17 PM CDT | Severe Thunderstorm Warning | LSX | Iron, Reynolds | 43 min |
| Apr 9, 7:18 PM CDT | Severe Thunderstorm Warning | LSX | Madison | 13 min |
| Apr 9, 7:26 PM CDT | Tornado Warning | LSX | Macoupin, Montgomery | 34 min |
| Apr 9, 7:27 PM CDT | Severe Thunderstorm Warning | LSX | Madison, Montgomery | 37 min |
| Apr 9, 7:30 PM CDT | Severe Thunderstorm Warning | LSX | Macoupin, Madison, Montgomery | 30 min |
| Apr 9, 7:54 PM CDT | Severe Thunderstorm Warning | LSX | Bond, Fayette, Montgomery | 51 min |
| Apr 9, 7:59 PM CDT | Severe Thunderstorm Warning | LSX | Iron, Madison, Reynolds | 46 min |
| Apr 9, 8:23 PM CDT | Tornado Warning | LSX | Fayette | 14 min |
| Apr 9, 8:45 PM CDT | Severe Thunderstorm Warning | LSX | Fayette | 30 min |
| Apr 9, 8:45 PM CDT | Severe Thunderstorm Warning | LSX | Madison | 26 min |
| Apr 9, 9:21 PM CDT | Severe Thunderstorm Warning | LSX | Washington | 39 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
Lincoln, IL (KILX), launched 12:00Z, 9.7 hours before the alert went out and 224 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
- 114 J/kg
- Mixed-layer CIN
- -122 J/kg
- Mixed-layer LCL
- 1085 m above ground
- 0-6 km bulk shear
- 26 kt
- 0-1 km storm-relative helicity
- 140 m²/s²
- 0-3 km storm-relative helicity
- 172 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.4
The text
As transmitted, in the capitals the NWS used until 2016.
148
WWUS20 KWNS 092138
SEL6
SPC WW 092138
ILZ000-MOZ000-100400-
URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 46
NWS STORM PREDICTION CENTER NORMAN OK
440 PM CDT THU APR 9 2015
THE NWS STORM PREDICTION CENTER HAS ISSUED A
* TORNADO WATCH FOR PORTIONS OF
WEST CENTRAL ILLINOIS
EAST CENTRAL MISSOURI
* EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 440 PM UNTIL
1100 PM CDT.
* PRIMARY THREATS INCLUDE...
A FEW TORNADOES POSSIBLE
SCATTERED LARGE HAIL LIKELY WITH ISOLATED VERY LARGE HAIL EVENTS
TO 2.5 INCHES IN DIAMETER POSSIBLE
SCATTERED DAMAGING WIND GUSTS TO 70 MPH LIKELY
THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 60 STATUTE
MILES EAST AND WEST OF A LINE FROM 55 MILES NORTH NORTHEAST OF
ALTON ILLINOIS TO 45 MILES SOUTHWEST OF FARMINGTON MISSOURI. FOR
A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU6).
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 39...WW 40...WW 41...WW
42...WW 43...WW 44...WW 45...
DISCUSSION...THUNDERSTORMS OVER CENTRAL MO WILL TRACK EASTWARD AND
INTENSIFY THIS AFTERNOON AND EVENING...SPREADING ACROSS THE WATCH
AREA. STRENGTHENING LOW LEVEL WINDS AND MODERATE INSTABILITY WILL
PROMOTE A RISK OF SUPERCELL STORMS CAPABLE OF LARGE HAIL...DAMAGING
WINDS...AND ISOLATED TORNADOES.
AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 24035.
...HARTSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 8, 7:04 PM CDT | Mesoscale Discussion | SPC | Franklin, Gallatin, Hardin, Jackson, Johnson, Pope and 3 more | 116 min |
| Apr 9, 12:29 PM CDT | Mesoscale Discussion | SPC | Bureau, Carroll, Henderson, Henry, Jo Daviess, Knox and 8 more | 91 min |
| Apr 9, 12:58 PM CDT | Tornado Watch | SPC | Adams, Brown, Carroll, Hancock, Henderson, Henry and 8 more | 6 hr |
| Apr 9, 1:48 PM CDT | Tornado Watch | SPC | Boone, Bureau, Cass, Champaign, Christian, Cook and 36 more | 9 hr |
| Apr 9, 3:12 PM CDT | Mesoscale Discussion | SPC | Adams, Boone, Brown, Bureau, Calhoun, Carroll and 51 more | 93 min |
| Apr 9, 3:45 PM CDT | Mesoscale Discussion | SPC | Alexander, Bond, Clay, Clinton, Cumberland, Effingham and 25 more | 60 min |
| Apr 9, 6:04 PM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, Cass, DeKalb, DeWitt and 37 more | 86 min |
| Apr 9, 6:48 PM CDT | Tornado Watch | SPC | Alexander, Clark, Clay, Coles, Crawford, Cumberland and 26 more | 6 hr |
| Apr 9, 1:32 PM CDT | Mesoscale Discussion | SPC | Barry, Barton, Benton, Camden, Cedar, Dade and 11 more | 118 min |
| Apr 9, 2:32 PM CDT | Severe Thunderstorm Watch | SPC | Barry, Benton, Camden, Christian, Dade, Dallas and 22 more | 7 hr |
| Apr 9, 6:11 PM CDT | Mesoscale Discussion | SPC | Butler, Carter, Dunklin, Mississippi, New Madrid, Oregon and 5 more | 64 min |
| Apr 9, 6:32 PM CDT | Severe Thunderstorm Watch | SPC | Dunklin, Pemiscot | 5 hr |
Nearby
Tornado Watches in Illinois, 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.