Alert archive / Nebraska / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 321, NWS Omaha, NE

August 18, 2011Cedar County, Nebraska

NWS Omaha, NE issued this severe thunderstorm warning at Aug 18, 2011, 5:28 PM CDT for Cedar County, Nebraska. It was in force for 47 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Aug 18, 2011, 5:28 PM CDT (22:28 UTC)
Expired: Aug 18, 2011, 6:15 PM CDT
In force: 47 min
Issued by: NWS Omaha, NE
Area: Storm-based polygon
Hail: 1.75 in
Wind: 60.0 mph

County Cedar County, NE

The radar

The Sioux Falls radar (KFSD), 97 km from the middle of the area, began a volume at 22:29 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 was reported inside it

Time	Report	Where	Remark
Aug 18, 5:43 PM CDT	HAIL 2	St. Helena, NE

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

Did it verify

Verified. The Iowa Environmental Mesonet's Cow matched one storm report to this severe thunderstorm warning; the first came 15 minutes after it went out.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Aug 18, 1:27 PM CDT	Severe Thunderstorm Watch	SPC	8 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 10.5 hours before the alert went out and 178 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: 1181 J/kg
Mixed-layer CIN: -126 J/kg
Mixed-layer LCL: 683 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 234 m²/s²
0-3 km storm-relative helicity: 385 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 11.7

Open this sounding in Storm Lab

The text

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

031 
WUUS53 KOAX 182228
SVROAX
NEC027-182315-
/O.NEW.KOAX.SV.W.0321.110818T2228Z-110818T2315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
528 PM CDT THU AUG 18 2011

THE NATIONAL WEATHER SERVICE IN OMAHA HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHERN CEDAR COUNTY IN NORTHEAST NEBRASKA...

* UNTIL 615 PM CDT

* AT 526 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING GOLF BALL SIZE HAIL...AND
  DAMAGING WINDS OF AROUND 60 MPH OR HIGHER.  THIS STORM WAS LOCATED
  5 MILES SOUTH OF MISSION HILL...OR 7 MILES SOUTHEAST OF YANKTON...
  AND MOVING SOUTHEAST AT 40 MPH.

* THE SEVERE THUNDERSTORM WILL AFFECT...
  ST. HELENA...WYNOT...AND OBERT. 

OTHER LOCATIONS IMPACTED BY THIS SEVERE THUNDERSTORM INCLUDE OBERT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF YOU ARE IN THE PATH OF THIS STORM...PREPARE IMMEDIATELY FOR LARGE
HAIL AND DAMAGING WINDS. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING AND AWAY FROM WINDOWS.

&&

LAT...LON 4286 9729 4286 9724 4285 9721 4281 9721
      4281 9717 4277 9713 4278 9707 4276 9701
      4246 9701 4268 9749 4287 9738 4286 9734
      4287 9730
TIME...MOT...LOC 2228Z 294DEG 34KT 4284 9725
WIND...HAIL 60MPH 1.75IN

$$

DP/CZ

1 follow-up statement

066 
WWUS53 KOAX 182253
SVSOAX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
553 PM CDT THU AUG 18 2011

NEC027-182315-
/O.CON.KOAX.SV.W.0321.000000T0000Z-110818T2315Z/
CEDAR NE-
553 PM CDT THU AUG 18 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR NORTHERN CEDAR
COUNTY UNTIL 615 PM CDT...

AT 553 PM CDT...PUBLIC REPORTED A SEVERE THUNDERSTORM PRODUCING GOLF 
BALL SIZE HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM 
WAS LOCATED NEAR VERMILLION...MOVING SOUTHEAST AT 30 MPH.

LOCATIONS IMPACTED INCLUDE...RURAL AREAS.  

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 60 MILES PER
HOUR...DESTRUCTIVE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN. FOR
YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST LEVEL OF YOUR
HOME OR BUSINESS. HEAVY RAIN CAN FLOOD ROADS QUICKLY SO DO NOT DRIVE
INTO AREAS WHERE WATER COVERS THE ROAD.

PREPARE IMMEDIATELY FOR LARGE HAIL AND DAMAGING WINDS IF YOU ARE IN
THE PATH OF THIS STORM. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING AND AWAY FROM WINDOWS.

&&

LAT...LON 4286 9729 4286 9724 4285 9721 4281 9721
      4281 9717 4277 9713 4278 9707 4276 9701
      4246 9701 4268 9749 4287 9738 4286 9734
      4287 9730
TIME...MOT...LOC 2252Z 294DEG 34KT 4275 9697
WIND...HAIL 60MPH 1.75IN

$$

ZAPOTOCNY

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Omaha, NE wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 18, 3:18 PM CDT, 2 hours 10 minutes earlier.

Area forecast discussion, Aug 18, 3:18 PM CDT, 2 hours 10 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
318 PM CDT THU AUG 18 2011

.DISCUSSION...

TONIGHT...
THE MAIN FORECAST CONCERN IS POTENTIAL FOR SEVERE THUNDERSTORMS...
ESPECIALLY PRIOR TO 1 AM CDT. ONGOING MESOSCALE CONVECTIVE SYSTEM
SHOULD CONTINUE TO EXPAND IN COVERAGE...THEN PUSH SOUTHEAST OUT OF
THE AREA. DECENT INSTABILITY WAS NOTED IN 18Z KOAX SOUNDING WITH
CAPE VALUES AROUND 3000 J/KG. PRECIPITABLE WATER VALUE WAS OVER
1.50 INCHES AND HAVE HAD SOME RAINFALL REPORTS OVER 1 INCH SO FAR.
SOUTHERLY WINDS SHOULD TURN MORE TOWARD THE EAST AND NORTHEAST
OVERNIGHT WITH LOWS 60 TO 65 NORTH AND MID TO UPPER 60S SOUTH.

TONIGHT THROUGH MID PART OF NEXT WEEK...
A FRONTAL BOUNDARY WILL SAG SOUTH
THROUGH THE AREA FRIDAY...BUT IT ONLY LOOKS LIKE A SLIGHT CHANCE
OF STORMS. THE 12Z NAM WAS FAIRLY AGGRESSIVE WITH DEVELOPMENT OF
STORMS NORTHEAST OF A LINE FROM KOFK TO KOMA FRIDAY AFTERNOON.
THAT SEEMED A BIT BULLISH BUT WILL MENTION SOME CHANCE OF SHOWERS
AND THUNDERSTORMS IN THE AFTERNOON.

SEVERAL SHORTWAVE TROUGHS WILL MOVE ACROSS THE LOCAL AREA IN THE
NORTHWEST FLOW ALOFT FRIDAY NIGHT THROUGH SATURDAY. KEPT PREVIOUS
FAIRLY HIGH RAIN CHANCES GOING. TEMPERATURES WILL BE BELOW NORMAL
SATURDAY WITH HIGHS 75 TO 80 NORTH AND 80 TO 85 SOUTH. COOL HIGH
PRESSURE AND DRY CONDITIONS ARE EXPECTED TO BUILD IN FOR SATURDAY
NIGHT...WITH LOWS MOSTLY 60 TO 65 BUT SOME UPPER 50S POSSIBLE
(ESPECIALLY NORTH).

THE PATTERN WILL REMAIN SOMEWHAT UNSETTLED SUNDAY NIGHT INTO
MONDAY NIGHT WITH NORTHWEST FLOW CONTINUING. IT DOES APPEAR THAT
THE 500 MB RIDGE WILL EXPAND EAST FROM THE ROCKIES AND INTO THE
PLAINS WHICH COULD PUSH TEMPERATURES (ESPECIALLY HIGHS) TO ABOVE
NORMAL LEVELS NEXT WEEK. THE 12Z ECMWF SHOWED A FAIRLY DECENT
SHORTWAVE DROPPING DOWN INTO IOWA TUESDAY INTO WEDNESDAY. THE
GFS WAS NOT AS AGGRESSIVE SO FOR NOW WILL JUST KEEP AN EYE ON
THAT.

&&

.AVIATION...
FOR TAF SITES KOFK/KOMA/KLNK

18Z TAFS

THUNDERSTORMS ARE MOST LIKELY TO AFFECT KOMA BUT MAY ALSO IMPACT
KLNK AND KOFK...MOSTLY PRIOR TO 05Z. SOME VISIBILITY REDUCTION
IS POSSIBLE TOWARD SUNRISE BUT SHOULD BECOME VFR BY MID MORNING.
MVFR CEILINGS APPEAR POSSIBLE FRIDAY AFTERNOON...MAINLY AT KOFK.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&

MILLER

Hazardous weather outlook, Aug 18, 4:15 PM CDT, 1 hour 13 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
415 PM CDT THU AUG 18 2011

IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034-
042>045-050>053-065>068-078-088>093-191100-
ANTELOPE-BOONE-BURT-BUTLER-CASS-CEDAR-COLFAX-CUMING-DODGE-DOUGLAS-
FREMONT IA-GAGE-HARRISON IA-JEFFERSON-JOHNSON-KNOX-LANCASTER-MADISON-
MILLS IA-MONONA IA-MONTGOMERY IA-NEMAHA-OTOE-PAGE IA-PAWNEE-PIERCE-
PLATTE-POTTAWATTAMIE IA-RICHARDSON-SALINE-SARPY-SAUNDERS-SEWARD-
SHELBY IA-STANTON-THURSTON-WASHINGTON-WAYNE-
415 PM CDT THU AUG 18 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR MOST OF EASTERN NEBRASKA AND
PARTS OF SOUTHWEST IOWA.

.DAY ONE...TONIGHT AND FRIDAY.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT THIS EVENING FOR MUCH
OF THE AREA. SCATTERED THUNDERSTORMS SHOULD CONTINUE. SOME STORMS
WILL PRODUCE DAMAGING WINDS AND LARGE HAIL. LOCALLY HEAVY RAIN IS
ALSO EXPECTED...WITH SOME SPOTS POSSIBLY RECEIVING OVER 2 INCHES.

THERE IS A SMALL CHANCE FOR THUNDERSTORMS FOR PORTIONS OF THE AREA
FRIDAY AFTERNOON...BUT SEVERE WEATHER IS NOT LIKELY.

MINOR TO MODERATE FLOODING CONTINUES ALONG THE MISSOURI RIVER.

.DAYS TWO THROUGH SEVEN...FRIDAY NIGHT THROUGH THURSDAY

ANOTHER ROUND OF THUNDERSTORMS IS FORECAST FROM FRIDAY EVENING
THROUGH SATURDAY EVENING. AT THIS TIME...SEVERE THUNDERSTORMS ARE
NOT EXPECTED. ADDITIONAL SMALL CHANCES FOR THUNDERSTORMS ARE
EXPECTED SUNDAY NIGHT INTO MONDAY NIGHT.

MINOR TO MODERATE FLOODING WILL CONTINUE ALONG THE MISSOURI RIVER
FOR THE NEXT SEVERAL WEEKS.

.SPOTTER INFORMATION STATEMENT...

STORM SPOTTERS SHOULD SHOULD PASS ALONG ANY OCCURRENCES OF HAIL...
DAMAGING WINDS OR FLASH FLOODING.

MILLER

In the hours before

Local storm report, Aug 18, 5:04 PM CDT, 24 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
504 PM CDT THU AUG 18 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0501 PM     HAIL             2 NW FORT CALHOUN       41.48N 96.05W
08/18/2011  E2.50 INCH       WASHINGTON         NE   TRAINED SPOTTER

            WINDS ESTIMATED AT 70 MPH.

&&

LANDSVORK

Special weather statement, Aug 18, 5:13 PM CDT, 15 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
513 PM CDT THU AUG 18 2011

NEZ012-182300-
CEDAR NE-
513 PM CDT THU AUG 18 2011

...SPECIAL WEATHER STATEMENT FOR EASTERN CEDAR COUNTY UNTIL 600 PM
CDT...

AT 507 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE TRACKING
A STRONG THUNDERSTORM 7 MILES SOUTH OF NEWCASTLE...OR 16 MILES SOUTH
OF VERMILLION.  THIS STORM WAS MOVING EAST AT 20 MPH.

HAIL UP TO THE SIZE OF NICKELS IS EXPECTED WITH THIS STORM.

LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE...
MAINLY RURAL AREAS OF EASTERN CEDAR COUNTY.

THIS STORM MAY INTENSIFY. MONITOR LOCAL RADIO AND TV STATIONS...AS
WELL AS LOCAL CABLE TV OUTLETS...FOR ADDITIONAL INFORMATION AND
POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.

DP/CZ

Local storm report, Aug 18, 5:15 PM CDT, 13 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
515 PM CDT THU AUG 18 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0510 PM     HAIL             OMAHA                   41.26N 96.01W
08/18/2011  E1.75 INCH       DOUGLAS            NE   TRAINED SPOTTER

            UP TO GOLFBALL SIZE HAIL NEAR 40TH STREET AND NORTH POST
            ROAD.

0512 PM     HAIL             OMAHA                   41.26N 96.01W
08/18/2011  E2.75 INCH       DOUGLAS            NE   TRAINED SPOTTER

            UP TO SOFTBALL SIZE HAIL AT INTERSTATE 680 AND 48TH
            STREET

&&

MILLER

Local storm report, Aug 18, 5:24 PM CDT, 4 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
524 PM CDT THU AUG 18 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0518 PM     HAIL             1 N OMAHA               41.28N 96.01W
08/18/2011  E1.75 INCH       DOUGLAS            NE   AMATEUR RADIO

&&

LANDSVORK

Local storm report, Aug 18, 5:26 PM CDT, 2 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
526 PM CDT THU AUG 18 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0524 PM     HAIL             OMAHA                   41.26N 96.01W
08/18/2011  M3.00 INCH       DOUGLAS            NE   CO-OP OBSERVER

            AT LEAST ONE BROKEN WINDOW IN FLORENCE AREA.

&&

RCHERMOK

Local storm report, Aug 18, 5:28 PM CDT, 0 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
528 PM CDT THU AUG 18 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0522 PM     TSTM WND GST     OMAHA                   41.26N 96.01W
08/18/2011  M62 MPH          DOUGLAS            NE   ASOS

&&

RCHERMOK

The office that day

Everything else NWS Omaha, NE issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 18, 12:32 PM CDT	Severe Thunderstorm Warning	OAX	Knox	43 min
Aug 18, 12:56 PM CDT	Severe Thunderstorm Warning	OAX	Cedar, Knox, Pierce	49 min
Aug 18, 1:22 PM CDT	Severe Thunderstorm Warning	OAX	Cedar, Knox, Wayne	53 min
Aug 18, 3:14 PM CDT	Severe Thunderstorm Warning	OAX	Cedar	46 min
Aug 18, 3:44 PM CDT	Severe Thunderstorm Warning	OAX	Burt, Dodge, Washington	46 min
Aug 18, 3:57 PM CDT	Severe Thunderstorm Warning	OAX	Pierce, Wayne	63 min
Aug 18, 3:59 PM CDT	Severe Thunderstorm Warning	OAX	Cedar	20 min
Aug 18, 4:17 PM CDT	Severe Thunderstorm Warning	OAX	Burt, Washington	43 min
Aug 18, 4:48 PM CDT	Severe Thunderstorm Warning	OAX	Antelope, Knox	57 min
Aug 18, 4:53 PM CDT	Severe Thunderstorm Warning	OAX	Thurston	52 min
Aug 18, 4:56 PM CDT	Severe Thunderstorm Warning	OAX	Douglas, Washington	49 min
Aug 18, 5:20 PM CDT	Severe Thunderstorm Warning	OAX	Cass, Douglas, Sarpy	40 min
Aug 18, 5:25 PM CDT	Tornado Warning	OAX	Antelope	50 min
Aug 18, 5:37 PM CDT	Severe Thunderstorm Warning	OAX	Antelope, Knox, Pierce	38 min
Aug 18, 5:41 PM CDT	Flash Flood Warning	OAX	Douglas, Washington	5 hr
Aug 18, 5:43 PM CDT	Severe Thunderstorm Warning	OAX	Burt, Thurston	47 min
Aug 18, 5:50 PM CDT	Flash Flood Warning	OAX	Thurston	6 hr
Aug 18, 6:01 PM CDT	Tornado Warning	OAX	Antelope, Knox	44 min
Aug 18, 6:08 PM CDT	Tornado Warning	OAX	Antelope	52 min
Aug 18, 6:15 PM CDT	Severe Thunderstorm Warning	OAX	Burt, Cuming, Thurston, Wayne	45 min
Aug 18, 6:25 PM CDT	Flash Flood Warning	OAX	Antelope	3 hr
Aug 18, 6:42 PM CDT	Severe Thunderstorm Warning	OAX	Burt, Washington	48 min
Aug 18, 6:56 PM CDT	Severe Thunderstorm Warning	OAX	Burt, Cuming, Dodge, Thurston	33 min
Aug 18, 6:57 PM CDT	Tornado Warning	OAX	Antelope, Boone, Madison	32 min

Nearby

Severe Thunderstorm Warnings in Nebraska, 2011 Every severe thunderstorm warning 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.