Alert archive / Nebraska / Severe Thunderstorm Watches in 2012

Severe Thunderstorm Watch 302

May 26, 201221 counties in Nebraska

The Storm Prediction Center issued this severe thunderstorm watch at May 26, 2012, 3:48 PM MDT for 21 counties in Nebraska. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: May 26, 2012, 3:48 PM MDT (21:48 UTC)
Expired: May 26, 2012, 9:00 PM MDT
In force: 5 hr
Issued by: the Storm Prediction Center
Largest hail expected: 2 in
Strongest gust expected: 60 kt

All 21 counties

Arthur County, NE, Blaine County, NE, Boyd County, NE, Brown County, NE, Cherry County, NE, Custer County, NE, Garden County, NE, Garfield County, NE, Grant County, NE, Holt County, NE, Hooker County, NE, Keith County, NE, Keya Paha County, NE, Lincoln County, NE, Logan County, NE, Loup County, NE, McPherson County, NE, Rock County, NE, Sheridan County, NE, Thomas County, NE, Wheeler County, NE

The radar

The North Platte radar (KLNX), 43 km from the middle of the area, began a volume at 21:49 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: 20%
One or more EF2 to EF5 tornadoes: 5%
Ten or more severe wind reports: 30%
One or more gusts of 65 knots or more: 30%
Ten or more severe hail reports: 40%
One or more hailstones of 2 inches or more: 20%
Six or more combined severe hail and wind reports: 80%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
May 26, 5:08 PM MDT	Severe Thunderstorm Warning	LBF	Holt, Wheeler	51 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

N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 9.8 hours before the alert went out and 131 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 298 J/kg
Mixed-layer CIN: -618 J/kg
Mixed-layer LCL: 581 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 387 m²/s²
0-3 km storm-relative helicity: 377 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

554 
WWUS20 KWNS 262147
SEL2
SPC WW 262147
NEZ000-270300-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 302
NWS STORM PREDICTION CENTER NORMAN OK
450 PM CDT SAT MAY 26 2012

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

       CENTRAL NEBRASKA

EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 450 PM UNTIL
1000 PM 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 70 MILES WEST OF
MULLEN NEBRASKA TO 20 MILES SOUTHEAST OF ONEILL NEBRASKA.  FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU2).

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...CONTINUE...WW 300...WW 301...

DISCUSSION...SCATTERED THUNDERSTORMS ARE INCREASING ALONG RETREATING
WARM FRONT OVER WESTERN NEB.  THESE STORMS WILL LIFT NORTHEASTWARD
ACROSS THE WATCH AREA THIS EVENING.  STEEP LOW/MID LEVEL LAPSE RATES
AND MODERATE INSTABILITY...COMBINED WITH FAVORABLE DEEP LAYER
EFFECTIVE SHEAR WILL POSE A RISK OF A FEW SUPERCELLS.  LARGE HAIL
AND DAMAGING WINDS ARE POSSIBLE IN THE STRONGEST STORMS.

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 24025.


...HART

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 25, 8:17 PM MDT	Mesoscale Discussion	SPC	Adams, Boone, Buffalo, Burt, Butler, Cass and 43 more	88 min
May 25, 11:46 PM MDT	Mesoscale Discussion	SPC	Burt, Dakota, Thurston	89 min
May 26, 12:58 AM MDT	Mesoscale Discussion	SPC	Boyd, Holt, Keya Paha, Knox, Rock	92 min
May 26, 2:48 PM MDT	Mesoscale Discussion	SPC	Adams, Antelope, Boone, Buffalo, Burt, Butler and 50 more	87 min
May 26, 2:55 PM MDT	Mesoscale Discussion	SPC	Arthur, Banner, Box Butte, Cheyenne, Deuel, Garden and 7 more	2 hr
May 26, 5:44 PM MDT	Mesoscale Discussion	SPC	Arthur, Blaine, Brown, Cherry, Garden, Garfield and 9 more	91 min

Nearby

Severe Thunderstorm Watches in Nebraska, 2012 Every 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.