Alert archive / Nebraska / Tornado Watches in 2011
Tornado Watch 398
The Storm Prediction Center issued this tornado watch at May 29, 2011, 7:16 PM CDT for 6 counties in Iowa; 4 counties in Kansas; 17 counties in Nebraska. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- May 29, 2011, 7:16 PM CDT (00:16 UTC)
- Expired
- May 29, 2011, 11:00 PM CDT
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 3 in
- Strongest gust expected
- 65 kt
All 27 counties
Fremont County, IA, Harrison County, IA, Mills County, IA, Montgomery County, IA, Pottawattamie County, IA, Shelby County, IA, Jewell County, KS, Mitchell County, KS, Osborne County, KS, Smith County, KS, Cass County, NE, Douglas County, NE, Fillmore County, NE, Gage County, NE, Jefferson County, NE, Johnson County, NE, Lancaster County, NE, Nemaha County, NE, Nuckolls County, NE, Otoe County, NE, Pawnee County, NE, Saline County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Thayer County, NE, Washington County, NE
The radar
The Grand Island radar (KUEX), 99 km from the middle of the area, began a volume at 00:16 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
- 30%
- Six or more combined severe hail and wind reports
- 80%
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 |
|---|---|---|---|---|
| May 29, 7:38 PM CDT | Severe Thunderstorm Warning | GID | Jewell, Mitchell, Osborne | 39 min |
| May 29, 8:06 PM CDT | Severe Thunderstorm Warning | GID | Smith | 20 min |
| May 29, 9:29 PM CDT | Severe Thunderstorm Warning | OAX | Jefferson | 31 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 00:00Z, 0.3 hours before the alert went out and 135 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
- 3559 J/kg
- Mixed-layer CIN
- -87 J/kg
- Mixed-layer LCL
- 597 m above ground
- 0-6 km bulk shear
- 49 kt
- 0-1 km storm-relative helicity
- 440 m²/s²
- 0-3 km storm-relative helicity
- 720 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 59.8
The text
As transmitted, in the capitals the NWS used until 2016.
078
WWUS20 KWNS 300017
SEL8
SPC WW 300017
IAZ000-KSZ000-NEZ000-300400-
URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 398
NWS STORM PREDICTION CENTER NORMAN OK
715 PM CDT SUN MAY 29 2011
THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF
PARTS OF SOUTHWEST IOWA
SMALL PART OF NORTH CENTRAL KANSAS
SOUTHEAST NEBRASKA
EFFECTIVE THIS SUNDAY EVENING FROM 715 PM UNTIL 1100 PM CDT.
TORNADOES...HAIL TO 3 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 75 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.
THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 50 STATUTE
MILES EAST AND WEST OF A LINE FROM 20 MILES WEST SOUTHWEST OF
CONCORDIA KANSAS TO 25 MILES NORTH 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 396...WW 397...
DISCUSSION...EXTREME INSTABILITY COUPLED WITH STRONGLY VEERING SHEAR
PROFILES ALONG WARM FRONT SUPPORT POTENTIAL FOR TORNADIC SUPERCELLS.
CINH AND WARM AIR ALOFT HAVE BEEN THE CONCERN...HOWEVER STORMS
CONTINUE TO DEVELOP ALONG BOUNDARY INDICATING CINH HAS WEAKENED.
WHILE FOCUSED...RAPID DEVELOPMENT OF SUPERCELLS IS BECOMING MORE
LIKELY ALONG WITH THREAT OF VERY LARGE HAIL AND TORNADOES.
AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 65 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
600. MEAN STORM MOTION VECTOR 24035.
...HALESSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 29, 9:24 PM CDT | Mesoscale Discussion | SPC | Audubon, Crawford, Harrison, Ida, Mills, Monona and 5 more | 96 min |
| May 29, 10:58 PM CDT | Severe Thunderstorm Watch | SPC | Dickinson, Lyon, O'Brien, Osceola, Plymouth, Sioux | 6 hr |
| May 30, 3:33 PM CDT | Mesoscale Discussion | SPC | Clark, Edwards, Ellis, Ford, Gove, Graham and 12 more | 87 min |
| May 30, 1:40 PM CDT | Mesoscale Discussion | SPC | Antelope, Blaine, Boone, Boyd, Buffalo, Cedar and 16 more | 95 min |
| May 30, 2:08 PM CDT | Tornado Watch | SPC | Adams, Antelope, Blaine, Boone, Boyd, Brown and 29 more | 7 hr |
| May 30, 2:19 PM CDT | Mesoscale Discussion | SPC | Arthur, Cheyenne, Deuel, Garden, Keith, Kimball and 1 more | 56 min |
| May 30, 4:45 PM CDT | Severe Thunderstorm Watch | SPC | Arthur, Chase, Cherry, Deuel, Dundy, Garden and 9 more | 3 hr |
| May 30, 5:47 PM CDT | Mesoscale Discussion | SPC | Arthur, Brown, Chase, Cherry, Deuel, Dundy and 9 more | 58 min |
| May 30, 6:17 PM CDT | Mesoscale Discussion | SPC | Adams, Antelope, Blaine, Boone, Boyd, Brown and 25 more | 118 min |
Nearby
Tornado Watches in Nebraska, 2011Tornado Watches in Iowa, 2011Tornado Watches in Kansas, 2011Every tornado watch in 2011
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.