Alert archive / Nebraska / Severe Thunderstorm Warnings in 2007

Severe Thunderstorm Warning 252, NWS Omaha, NE

August 11, 2007Knox County, Nebraska

NWS Omaha, NE issued this severe thunderstorm warning at Aug 11, 2007, 12:38 AM CDT for Knox County, Nebraska. It was in force for 29 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 11, 2007, 12:38 AM CDT (05:38 UTC)
Expired
Aug 11, 2007, 1:07 AM CDT
In force
29 min
Issued by
NWS Omaha, NE
Area
Counties, with a storm outline in the text

County Knox County, NE

The radar

The Sioux Falls radar (KFSD), 123 km from the middle of the area, began a volume at 05:40 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.

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 5.6 hours before the alert went out and 203 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 2007-08-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4503 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 2007-08-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 60 square meters per square second.193958Sfc1 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
4503 J/kg
Mixed-layer CIN
-8 J/kg
Mixed-layer LCL
1138 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
60 m²/s²
0-3 km storm-relative helicity
125 m²/s²
Significant tornado parameter
1.7
Supercell composite
12.1

Open this sounding in Storm Lab

The text

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

000 
WUUS53 KOAX 110539
SVROAX
NEC107-110630-
/O.NEW.KOAX.SV.W.0252.070811T0538Z-070811T0630Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
1238 AM CDT SAT AUG 11 2007

THE NATIONAL WEATHER SERVICE IN OMAHA HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  KNOX COUNTY IN NORTHEAST NEBRASKA...

* UNTIL 130 AM CDT

* AT 1236 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM.  THIS STORM WAS LOCATED NEAR SANTEE...OR ABOUT
  28 MILES WEST OF YANKTON...AND MOVING EAST AT 35 MPH.

* THE SEVERE THUNDERSTORM WILL AFFECT...
  SANTEE AND CROFTON

WIND GUSTS OVER 60 MPH ARE POSSIBLE WITH THIS STORM.

IF YOU ARE IN THE WARNED AREA...PREPARE FOR DAMAGING WINDS...LARGE
HAIL...HEAVY RAIN AND DANGEROUS LIGHTNING. GET INTO A REINFORCED
BUILDING. STAY AWAY FROM WINDOWS AND GLASS DOORS.

LAT...LON 4280 9810 4260 9798 4266 9749 4286 9748
      4285 9756 4286 9764 4284 9769 4285 9771
      4286 9773 4285 9778 4286 9782 4286 9787
      4283 9789 4279 9793 4277 9801

$$
2 follow-up statements
000 
WWUS53 KOAX 110548
SVSOAX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
1248 AM CDT SAT AUG 11 2007

NEC107-110630-
/O.CON.KOAX.SV.W.0252.000000T0000Z-070811T0630Z/
KNOX NE-
1248 AM CDT SAT AUG 11 2007

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 130 AM CDT
FOR KNOX COUNTY...

AT 1244 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS 60
TO 70 MPH.  THIS STORM WAS LOCATED NEAR SANTEE...OR ABOUT 22 MILES
WEST OF YANKTON...MOVING EAST AT 35 MPH.

LOCATIONS IMPACTED INCLUDE...CROFTON.

THIS STORM MAY PRODUCE WINDS OF 60 TO 70 MPH. GO TO THE LOWEST LEVEL
OF YOUR HOME OR BUSINESS. STAY AWAY FROM WINDOWS AND GLASS DOORS.

LAT...LON 4280 9810 4260 9798 4266 9749 4286 9748
      4285 9756 4286 9764 4284 9769 4285 9771
      4286 9773 4285 9778 4286 9782 4286 9787
      4283 9789 4279 9793 4277 9801

$$

DERGAN
000 
WWUS53 KOAX 110607
SVSOAX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
107 AM CDT SAT AUG 11 2007

NEC107-110617-
/O.CAN.KOAX.SV.W.0252.000000T0000Z-070811T0630Z/
KNOX NE-
107 AM CDT SAT AUG 11 2007

...THE SEVERE THUNDERSTORM WARNING FOR KNOX COUNTY IS CANCELLED...

THE STORM WHICH PROMPTED THE WARNING HAS EXITED THE WARNED 
AREA...THUS THE WARNING WHICH WAS IN EFFECT HAS BEEN CANCELLED. 

LAT...LON 4280 9810 4260 9798 4266 9749 4286 9748
      4285 9756 4286 9764 4284 9769 4285 9771
      4286 9773 4285 9778 4286 9782 4286 9787
      4283 9789 4279 9793 4277 9801

$$

DERGAN

Nearby

Severe Thunderstorm Warnings in Nebraska, 2007Every severe thunderstorm warning in 2007

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.