Alert archive / Iowa / Tornado Watches in 2012
Tornado Watch 168
The Storm Prediction Center issued this tornado watch at Apr 14, 2012, 2:56 PM CDT for 20 counties in Iowa. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 14, 2012, 2:56 PM CDT (19:56 UTC)
- Expired
- Apr 14, 2012, 5:01 PM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2.5 in
- Strongest gust expected
- 60 kt
Counties Adair County, IA, Adams County, IA, Appanoose County, IA, Audubon County, IA, Cass County, IA, Clarke County, IA, Dallas County, IA, Decatur County, IA, Guthrie County, IA, Jasper County, IA, Lucas County, IA, Madison County, IA, Marion County, IA, Monroe County, IA, Polk County, IA, Ringgold County, IA, Taylor County, IA, Union County, IA, Warren County, IA, Wayne County, IA
The radar
The Omaha radar (KOAX), 112 km from the middle of the area, began a volume at 19:56 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
- 30%
- One or more gusts of 65 knots or more
- 30%
- 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
- 70%
Warnings issued inside it
3 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 14, 3:47 PM CDT | Tornado Warning | DMX | Adair, Adams, Madison, Union | 28 min |
| Apr 14, 3:54 PM CDT | Severe Thunderstorm Warning | DMX | Adair, Madison | 36 min |
| Apr 14, 4:27 PM CDT | Severe Thunderstorm Warning | DMX | Madison, Warren | 48 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
Omaha, NE (KOAX), launched 12:00Z, 7.9 hours before the alert went out and 112 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
- 1847 m above ground
- 0-6 km bulk shear
- 38 kt
- 0-1 km storm-relative helicity
- 2 m²/s²
- 0-3 km storm-relative helicity
- 89 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
031
WWUS20 KWNS 141948
SEL8
SPC WW 141948
IAZ000-150200-
URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 168
NWS STORM PREDICTION CENTER NORMAN OK
250 PM CDT SAT APR 14 2012
THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF
SOUTHWEST IOWA
EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 250 PM UNTIL
900 PM CDT.
TORNADOES...HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.
THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 55 STATUTE
MILES EAST AND WEST OF A LINE FROM 40 MILES EAST SOUTHEAST OF
SHENANDOAH IOWA TO 60 MILES NORTHEAST OF OMAHA NEBRASKA. FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU8).
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 165...WW 166...WW 167...
DISCUSSION...A LARGE SUPERCELL STORM HAS FORMED OVER SOUTHWEST IA
AND IS EXPECTED TO TRACK EASTWARD ROUGHLY ALONG WARM FRONT FOR NEXT
FEW HOURS. OTHER LESS-INTENSE STORMS MAY ALSO SPREAD OUT OF EASTERN
NEB INTO WESTERN IA DURING THE NEXT FEW HOURS. TORNADOES...LARGE
HAIL...AND DAMAGING WINDS WILL BE POSSIBLE WITH THIS ACTIVITY.
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 25030.
...HARTSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 14, 12:00 PM CDT | Tornado Watch | SPC | Fremont, Harrison, Mills, Monona, Montgomery, Page and 2 more | 7 hr |
| Apr 14, 2:15 PM CDT | Mesoscale Discussion | SPC | Adams, Audubon, Cass, Fremont, Harrison, Mills and 5 more | 90 min |
| Apr 14, 4:47 PM CDT | Mesoscale Discussion | SPC | Adair, Adams, Appanoose, Cass, Clarke, Dallas and 17 more | 58 min |
| Apr 14, 5:00 PM CDT | Tornado Watch | SPC | Adair, Adams, Appanoose, Audubon, Cass, Clarke and 18 more | 7 hr |
| Apr 14, 6:57 PM CDT | Mesoscale Discussion | SPC | Adair, Adams, Appanoose, Audubon, Cass, Clarke and 23 more | 63 min |
Nearby
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.