Alert archive / Nebraska / Severe Thunderstorm Watches in 2012

Severe Thunderstorm Watch 244

May 4, 201240 counties in Nebraska

The Storm Prediction Center issued this severe thunderstorm watch at May 4, 2012, 11:00 PM CDT for 40 counties in Nebraska. It took effect at May 4, 2012, 11:05 PM CDT. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
May 4, 2012, 11:00 PM CDT (04:00 UTC)
In effect from
May 4, 2012, 11:05 PM CDT
Expired
May 5, 2012, 1:59 AM CDT
In force
3 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 40 counties

Adams County, NE, Boone County, NE, Buffalo County, NE, Burt County, NE, Butler County, NE, Cass County, NE, Clay County, NE, Colfax County, NE, Cuming County, NE, Custer County, NE, Dawson County, NE, Dodge County, NE, Douglas County, NE, Fillmore County, NE, Garfield County, NE, Greeley County, NE, Hall County, NE, Hamilton County, NE, Howard County, NE, Kearney County, NE, Lancaster County, NE, Loup County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Otoe County, NE, Platte County, NE, Polk County, NE, Saline County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Sherman County, NE, Stanton County, NE, Thurston County, NE, Valley County, NE, Washington County, NE, Wayne County, NE, Wheeler County, NE, York County, NE

The radar

The Grand Island radar (KUEX), 123 km from the middle of the area, began a volume at 04:02 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
10%
One or more EF2 to EF5 tornadoes
2%
Ten or more severe wind reports
20%
One or more gusts of 65 knots or more
20%
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

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

IssuedProductOfficeCountiesLasted
May 4, 11:03 PM CDTFlash Flood WarningOAXWayne4 hr
May 4, 11:06 PM CDTSevere Thunderstorm WarningOAXCuming, Thurston, Wayne54 min
May 4, 11:09 PM CDTSevere Thunderstorm WarningGIDHoward, Sherman36 min
May 4, 11:46 PM CDTSevere Thunderstorm WarningOAXColfax, Dodge44 min
May 5, 12:30 AM CDTSevere Thunderstorm WarningOAXButler, Colfax, Dodge, Saunders45 min
May 5, 12:33 AM CDTSevere Thunderstorm WarningOAXBurt, Dodge, Washington42 min
May 5, 12:46 AM CDTSevere Thunderstorm WarningOAXMadison, Stanton44 min
May 5, 1:09 AM CDTSevere Thunderstorm WarningOAXDodge21 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, 4.0 hours before the alert went out and 164 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, Omaha, NE at 00:00Z on 2012-05-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2635 joules per kilogram.LCLLFCEL10008507005003002001001 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, Omaha, NE at 00:00Z on 2012-05-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 71 square meters per square second.1939Sfc1 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
2635 J/kg
Mixed-layer CIN
-14 J/kg
Mixed-layer LCL
1505 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
71 m²/s²
0-3 km storm-relative helicity
173 m²/s²
Significant tornado parameter
0.6
Supercell composite
8.5

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

206 
WWUS20 KWNS 050402
SEL4
SPC WW 050402
NEZ000-051000-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 244
NWS STORM PREDICTION CENTER NORMAN OK
1105 PM CDT FRI MAY 4 2012

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

       CENTRAL AND EASTERN NEBRASKA

EFFECTIVE THIS FRIDAY NIGHT AND SATURDAY MORNING FROM 1105 PM
UNTIL 500 AM CDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 55
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 10 MILES SOUTH
SOUTHWEST OF BROKEN BOW NEBRASKA TO 35 MILES NORTHEAST OF LINCOLN
NEBRASKA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION...THIS SEVERE THUNDERSTORM WATCH REPLACES
SEVERE THUNDERSTORM WATCH NUMBER 241. WATCH NUMBER 241 WILL NOT
BE IN EFFECT AFTER 1105 PM CDT. CONTINUE...WW 243...

DISCUSSION...SEVERE STORMS ARE EXPECTED TO CONTINUE FOR ANOTHER FEW
HOURS ALONG A RESIDUAL OUTFLOW BOUNDARY...WHERE LOW-LEVEL WAA IS
FOCUSED ON THE NOSE OF 30 KT BRANCH OF THE LLJ.  STRONG INSTABILITY
WILL SUPPORT A RISK FOR LARGE HAIL/DAMAGING WINDS...PRIOR TO A
GRADUAL WEAKENING TREND IN THE EARLY MORNING HOURS AS CONVECTIVE
INHIBITION SLOWLY INCREASES.

AVIATION...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 500. MEAN STORM
MOTION VECTOR 32015.


...THOMPSON

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 4, 9:54 PM CDTMesoscale DiscussionSPCAdams, Antelope, Boone, Buffalo, Burt, Butler and 42 more96 min
May 4, 10:55 PM CDTMesoscale DiscussionSPCAdams, Antelope, Boone, Buffalo, Burt, Butler and 34 more35 min
May 5, 2:09 PM CDTMesoscale DiscussionSPCAntelope, Boone, Burt, Butler, Cedar, Colfax and 22 more96 min
May 5, 3:52 PM CDTMesoscale DiscussionSPCAntelope, Boone, Cedar, Cuming, Dakota, Dixon and 11 more83 min
May 5, 5:31 PM CDTTornado WatchSPCAntelope, Boone, Cedar, Custer, Dakota, Dawson and 15 more5 hr
May 5, 6:21 PM CDTMesoscale DiscussionSPCBoyd, Brown, Keya Paha, Rock, Thomas84 min
May 5, 6:44 PM CDTMesoscale DiscussionSPCBanner, Cheyenne, Kimball61 min
May 5, 6:46 PM CDTSevere Thunderstorm WatchSPCArthur, Blaine, Boyd, Brown, Cherry, Deuel and 10 more6 hr

Nearby

Severe Thunderstorm Watches in Nebraska, 2012Every severe thunderstorm watch in 2012

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.