Alert archive / Nebraska / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 64, NWS Omaha, NE

May 12, 2011Pottawattamie County, Iowa; Douglas County, Sarpy County, Nebraska

NWS Omaha, NE issued this severe thunderstorm warning at May 12, 2011, 10:06 PM CDT for Pottawattamie County, Iowa; Douglas County, Sarpy County, Nebraska. It was in force for 39 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: May 12, 2011, 10:06 PM CDT (03:06 UTC)
Expired: May 12, 2011, 10:45 PM CDT
In force: 39 min
Issued by: NWS Omaha, NE
Area: Storm-based polygon
Hail: 1.5 in
Wind: 50.0 mph

Counties Pottawattamie County, IA, Douglas County, NE, Sarpy County, NE

The radar

The Omaha radar (KOAX), 38 km from the middle of the area, began a volume at 03:06 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
May 12, 10:17 PM CDT	HAIL 1	Omaha, NE	NEAR 107TH AND IDA STREETS FAR NORTHWEST OMAHA.

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 11 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
May 12, 6:05 PM CDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 3.1 hours before the alert went out and 38 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: 1648 J/kg
Mixed-layer CIN: -45 J/kg
Mixed-layer LCL: 900 m above ground
0-6 km bulk shear: 17 kt
0-1 km storm-relative helicity: 19 m²/s²
0-3 km storm-relative helicity: 50 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.6

Open this sounding in Storm Lab

The text

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

701 
WUUS53 KOAX 130306
SVROAX
IAC155-NEC055-153-130345-
/O.NEW.KOAX.SV.W.0064.110513T0306Z-110513T0345Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
1006 PM CDT THU MAY 12 2011

THE NATIONAL WEATHER SERVICE IN OMAHA HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHWESTERN POTTAWATTAMIE COUNTY IN SOUTHWEST IOWA...
  DOUGLAS COUNTY IN EAST CENTRAL NEBRASKA...
  SARPY COUNTY IN EAST CENTRAL NEBRASKA...

* UNTIL 1045 PM CDT

* AT 1005 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING PING PONG BALL SIZE HAIL. 
  THIS STORM WAS LOCATED NEAR GRETNA...OR 13 MILES SOUTHWEST OF
  OMAHA...AND MOVING EAST AT 20 MPH.  THIS STORM PRODUCED QUARTER    
  SIZE HAIL NEAR GRETNA AT 1005 PM.

* LOCATIONS IMPACTED INCLUDE...
  OMAHA...SPRINGFIELD...MILLARD...PAPILLION...LA VISTA...RALSTON...
  BELLEVUE...COUNCIL BLUFFS...OFFUTT AFB...CHALCO...BOYS TOWN...
  BENNINGTON...LAKE MANAWA STATE PARK AND CARTER LAKE.

THE WARNED AREA INCLUDES INTERSTATE 80 IN NEBRASKA BETWEEN MILE
MARKERS 432 AND 454.

THE WARNED AREA INCLUDES INTERSTATE 80 IN IOWA BETWEEN MILE MARKERS 1
AND 3.

THE WARNED AREA INCLUDES INTERSTATE 29 IN IOWA BETWEEN MILE MARKERS
52 AND 55.

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 QUICKLY FLOOD ROADS...SO DO NOT
DRIVE INTO AREAS WHERE WATER COVERS THE ROAD.

TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD
TO FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED
ROADWAYS.

&&

LAT...LON 4116 9586 4116 9588 4114 9588 4113 9587
      4106 9588 4106 9596 4106 9597 4106 9600
      4107 9603 4106 9607 4107 9630 4135 9637
      4139 9595 4125 9584
TIME...MOT...LOC 0306Z 258DEG 17KT 4116 9619
WIND...HAIL <50MPH 1.50IN

$$

DERGAN

4 follow-up statements

074 
WWUS53 KOAX 130317
SVSOAX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
1017 PM CDT THU MAY 12 2011

IAC155-NEC055-153-130345-
/O.CON.KOAX.SV.W.0064.000000T0000Z-110513T0345Z/
POTTAWATTAMIE IA-DOUGLAS NE-SARPY NE-
1017 PM CDT THU MAY 12 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR SARPY...
DOUGLAS AND SOUTHWESTERN POTTAWATTAMIE COUNTIES UNTIL 1045 PM CDT...

AT 1011 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING PING PONG BALL
SIZE HAIL.  THIS STORM WAS LOCATED NEAR MILLARD...OR 9 MILES 
SOUTHWEST OF OMAHA...MOVING EAST AT 25 MPH.  IN 
ADDITION...TORRENTIAL RAIN CAN BE EXPECTED WHICH COULD PRODUCE FLASH 
FLOODING ALONG DITCHES AND CREEKS ACROSS PART OF THE AREA.

LOCATIONS IMPACTED INCLUDE...
  OMAHA...PAPILLION...LA VISTA...RALSTON...OFFUTT AFB...BELLEVUE...
  COUNCIL BLUFFS...CARTER LAKE AND LAKE MANAWA STATE PARK.

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.

TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD
TO FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED
ROADWAYS.

&&

LAT...LON 4116 9586 4116 9588 4114 9588 4113 9587
      4106 9588 4106 9596 4106 9597 4106 9600
      4107 9603 4106 9607 4107 9630 4135 9637
      4139 9595 4125 9584
TIME...MOT...LOC 0316Z 261DEG 20KT 4117 9610
WIND...HAIL <50MPH 1.50IN

$$

DERGAN

183 
WWUS53 KOAX 130324
SVSOAX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
1024 PM CDT THU MAY 12 2011

IAC155-NEC055-153-130345-
/O.CON.KOAX.SV.W.0064.000000T0000Z-110513T0345Z/
POTTAWATTAMIE IA-DOUGLAS NE-SARPY NE-
1024 PM CDT THU MAY 12 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR EASTERN
SARPY...DOUGLAS AND SOUTHWESTERN POTTAWATTAMIE COUNTIES UNTIL 1045 PM
CDT...

AT 1020 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS CONTINUED TO
INDICATE SEVERE THUNDERSTORMS CAPABLE OF PRODUCING PING PONG BALL 
SIZE HAIL OVER THE OMAHA METRO AREA. ONE STORM JUST SOUTH OF 
BENNINGTON PRODUCED QUARTER SIZE HAIL AT 1017 PM NEAR 107TH AND 
IDA.  ANOTHER SEVERE STORM PRODUCING LARGE HAIL WAS INDICATED NEAR 
PAPILLION...OR 8 MILES SOUTHWEST OF OMAHA.  THE STORMS WERE MOVING 
NORTH AND NORTHEAST AT AROUND 25 MPH.

LOCATIONS IMPACTED INCLUDE...
  OMAHA...PAPILLION...LA VISTA...RALSTON...OFFUTT AFB...BELLEVUE...
  COUNCIL BLUFFS...CARTER LAKE AND LAKE MANAWA STATE PARK.

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.

TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD
TO FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED
ROADWAYS.

&&

LAT...LON 4116 9586 4116 9588 4114 9588 4113 9587
      4106 9588 4106 9600 4107 9603 4106 9607
      4113 9616 4135 9631 4139 9595 4125 9584
TIME...MOT...LOC 0321Z 261DEG 20KT 4117 9606
WIND...HAIL <50MPH 1.50IN

$$

DERGAN

444 
WWUS53 KOAX 130334
SVSOAX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
1034 PM CDT THU MAY 12 2011

IAC155-NEC055-153-130345-
/O.CON.KOAX.SV.W.0064.000000T0000Z-110513T0345Z/
POTTAWATTAMIE IA-DOUGLAS NE-SARPY NE-
1034 PM CDT THU MAY 12 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR NORTHEASTERN
SARPY...DOUGLAS AND SOUTHWESTERN POTTAWATTAMIE COUNTIES UNTIL 1045 PM
CDT...

AT 1030 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE
HAIL.  THIS STORM WAS LOCATED NEAR SOUTH CENTRAL OMAHA...MOVING
NORTHEAST AT 30 MPH.

LOCATIONS IMPACTED INCLUDE...
  OMAHA...COUNCIL BLUFFS...CARTER LAKE AND LAKE MANAWA STATE PARK.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 60 MILES PER 
HOUR...DESTRUCTIVE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN.

TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD
TO FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED
ROADWAYS.

&&

LAT...LON 4116 9586 4116 9588 4113 9587 4112 9588
      4110 9599 4117 9606 4121 9616 4136 9622
      4139 9595 4125 9584
TIME...MOT...LOC 0334Z 244DEG 25KT 4122 9595
WIND...HAIL <50MPH 1.00IN

$$

DERGAN

363 
WWUS53 KOAX 130343
SVSOAX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
1043 PM CDT THU MAY 12 2011

IAC155-NEC055-153-130352-
/O.EXP.KOAX.SV.W.0064.000000T0000Z-110513T0345Z/
POTTAWATTAMIE IA-DOUGLAS NE-SARPY NE-
1043 PM CDT THU MAY 12 2011

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN SARPY...DOUGLAS
AND SOUTHWESTERN POTTAWATTAMIE COUNTIES WILL EXPIRE AT 1045 PM CDT...

THE STORM WHICH PROMPTED THE WARNING HAS WEAKENED BELOW SEVERE
LIMITS...AND NO LONGER POSES AN IMMEDIATE THREAT TO LIFE OR PROPERTY.
HOWEVER SMALL HAIL...GUSTY WINDS AND VERY HEAVY RAIN ARE STILL 
EXPECTED WITH THIS THUNDERSTORM UNTIL 1130 PM.  A FLASH FLOOD 
WARNING REMAINS IN EFFECT FOR THE OMAHA AREA UNTIL 4 AM.

LAT...LON 4116 9586 4116 9588 4113 9587 4112 9588
      4110 9599 4117 9606 4121 9616 4136 9622
      4139 9595 4125 9584
TIME...MOT...LOC 0342Z 244DEG 25KT 4124 9588

$$

DERGAN

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 May 12, 2:46 PM CDT, 7 hours 20 minutes earlier.

Area forecast discussion, May 12, 2:46 PM CDT, 7 hours 20 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
246 PM CDT THU MAY 12 2011

.DISCUSSION...

ONE MORE ACTIVE EVENING THEN PATTERN FLIPS BACK TO WHAT IT WAS
OVER THE LATTER HALF OF APRIL/EARLY MAY...COOL.

FOR TONIGHT...CURRENT WATER VAPOR SATELLITE IMAGERY SHOWED UPPER
LOW PIVOT POINT NEAR MCK AT 19Z. PRIOR TO THAT TIME SHOWER/ANY
CONVECTION WAS TIED MORE CLOSELY TO THE UPPER LOW ALTHOUGH THAT
WILL BE CHANGING INTO EVENING. CONVECTION SHOULD BECOME MORE
WIDESPREAD NEAR DRY LINE FROM SCNTRL NEBRASKA INTO KS WHICH WAS
PUNCHING UP TOWARD SERN NEBRASKA...AND ALSO POSSIBLY NEAR
BOUNDARY IN NERN NEBRASKA. WITH ACTIVITY LIKELY INCREASING ACROSS
THE FORECAST AREA PER 4KM WRF...CATEGORICAL POPS APPEAR IN ORDER
THIS EVENING DECREASING SOME AFTER 06Z AS STRONGEST CONVECTION
EITHER WEAKENS OR MOVES OUT BY THAT TIME. BESIDES LARGE HAIL
THREAT WITH LOW FREEZING LEVEL PER 18Z OAX SOUNDING...TORNADO
THREAT EXISTS AS LOW LEVEL SHEAR NEAR BOUNDARIES IS DECENT. LTL/NO
CHANGES TO MINIMUM TEMPERATURES TONIGHT WITH PREVIOUS FORECAST AND
MAV/MET BLEND ACCEPTED.

UPPED POPS FIRST HALF OF FRIDAY AS UPPER LOW APPEARS IT WILL BE A
BIT SLOWER TO DEPART. OTHERWISE...A CONSIDERABLE AMOUNT OF CLOUDS
EXPECTED THROUGH THE WEEKEND WITH TEMPERATURES MUCH BELOW NORMAL.
LOWERED HIGHS A BIT FRIDAY/SATURDAY AS THERE WAS STILL A STRONG
SIGNAL THAT A LOT OF LOW CLOUDS COULD LINGER IN NWRLY FLOW.
ADDED SMALL PRECIP CHANCES SATURDAY AFTERNOON NRN ZONES AS DECENT
RUN TO RUN SUPPORT AND AGREEMENT BETWEEN GFS/ECMWF AS UPPER LOW
NOW OVER SOUTHERN CANADA BEGINS DROPPING SWD. HOW FAR SOUTHWEST
THIS PRECIP SPREADS ON SUNDAY STILL IN QUESTION...AND AT THIS TIME
KEPT IT CONFINED TO ABOUT THE ERN 2/3RDS AS FORCING BECOMES A
LITTLE MORE QUESTIONABLE SW AS UPPER LOW COULD TEND TO OPEN UP OR
SHIFT MORE SE.

MADE LITTLE CHANGES TO MON-WED PERIODS AS HIGH AMPLITUDE UPPER
RIDGE SETS UP PULLING DOWN DRIER BUT STILL RELATIVELY COOL AIR.
KEPT MOST LOWS AROUND 40/LOWER 40S BUT SOME POTENTIAL FOR MID
30S/FROST SOME OF THOSE MORNINGS AND THIS COULD PROVIDE FOCUS FOR
FUTURE FORECASTS.

SOME QUESTION IN HOW MUCH ENERGY MANAGES TO UNDERCUT UPPER RIDGE
TOWARD END OF FORECAST PERIOD WITH GFS ENSEMBLE MEAN/PRIOR GFS RUNS
MORE BULLISH/FARTHER E. DECIDED TO INCLUDE SMALL PRECIP CHANCES
WED FAR SOUTHWEST AND ACROSS SW 1/2 OR SO WED NGT/THU. A SLIGHT
WARMING TREND SHOULD CONTINUE...ALTHOUGH KEPT HIGHS BELOW 70 ALL
AREAS.

&&

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

18Z TAFS

CONVECTION ONCE AGAIN WILL DISRUPT TAF FORECAST THIS
AFTERNOON/EVENING.  IN THE MEANTIME...CLOUD DECK THIS AFTERNOON IS
FLIRTING WITH VFR/MVFR LINE...BUT WILL BECOME MVFR FOLLOWING FRONTAL
PASSAGE/THUNDERSTORMS THIS EVENING THROUGH OVERNIGHT.  CONVECTION
THIS AFTERNOON/EVENING MAY BRING SHORT-LIVED MVFR TO IFR VIS/CIGS AS
WELL AS BRIEF GUSTY WINDS.  HAVE LIFTED CIGS AT ALL SITES DURING THE
LATE MORNING FRIDAY AS LOW MOVES AWAY...AND KEPT GUSTY NORTHWEST
WINDS FROM OVERNIGHT INTO THE MORNING.

&&

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

CHERMOK/MAYES

Hazardous weather outlook, May 12, 6:13 PM CDT, 3 hours 53 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
613 PM CDT THU MAY 12 2011

IAZ043-055-056-069-080-091-NEZ011-012-015>018-030>034-042>045-
050>053-065-066-078-088>090-092-131315-
MONONA-HARRISON-SHELBY-POTTAWATTAMIE-MONTGOMERY-PAGE-KNOX-CEDAR-
THURSTON-ANTELOPE-PIERCE-WAYNE-BOONE-MADISON-STANTON-CUMING-BURT-
PLATTE-COLFAX-DODGE-WASHINGTON-BUTLER-SAUNDERS-DOUGLAS-SARPY-
SEWARD-LANCASTER-SALINE-JEFFERSON-GAGE-JOHNSON-PAWNEE-
613 PM CDT THU MAY 12 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS EASTERN NEBRASKA
AND SOUTHWEST IOWA.

.DAY ONE...TONIGHT

THUNDERSTORMS WILL LIKELY OVERSPREAD MUCH OF THE AREA THIS EVENING
BEFORE WEAKENING AFTER MIDNIGHT. SOME OF THE STORMS MAY BE SEVERE
WITH LARGE HAIL AND ISOLATED TORNADOES THE PRIMARY THREATS. THE
TORNADO THREAT IS GENERALLY BEFORE 10 PM IN NEBRASKA SOUTHEAST OF
ALBION...NORFOLK AND WAYNE AND IN WESTERN IOWA MAINLY NORTH OF
COUNCIL BLUFFS. SOME OF THE HAIL COULD BE LARGER THAN GOLFBALL-
SIZE...AGAIN MOSTLY EAST SOUTHEAST OF THOSE TOWNS. LOW PRESSURE IN
NORTH CENTRAL KANSAS AND SEVERAL BOUNDARIES ACROSS THE AREA WERE
PROVIDING THE NECESSARY FORCING AND WIND SHEAR FOR THE SEVERE
WEATHER THREAT.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

ISOLATED THUNDERSTORMS ARE POSSIBLE OVER PARTS OF THE AREA LATE
NEXT WEDNESDAY INTO THURSDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED INTO THIS EVENING...PARTICULARLY
FROM AROUND THE HIGHWAY 30 CORRIDOR SOUTHWARD.

IAZ079-090-NEZ067-068-091-093-131315-
MILLS-FREMONT-CASS-OTOE-NEMAHA-RICHARDSON-
613 PM CDT THU MAY 12 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST IOWA
AND SOUTHEAST NEBRASKA.

.DAY ONE...TONIGHT

THUNDERSTORMS WILL LIKELY OVERSPREAD MUCH OF THE AREA THIS EVENING
BEFORE WEAKENING AFTER MIDNIGHT. SOME OF THE STORMS MAY BE SEVERE
WITH LARGE HAIL AND ISOLATED TORNADOES THE PRIMARY THREATS.  HOWEVER...
THE TORNADO THREAT IS GENERALLY BEFORE 10 PM AND MAINLY IN
NEBRASKA SOUTHEAST OF ALBION...NORFOLK AND WAYNE BUT NORTHWEST OF
FALLS CITY. LOW PRESSURE IN NORTH CENTRAL KANSAS AND SEVERAL
BOUNDARIES ACROSS THE AREA WERE PROVIDING THE NECESSARY FORCING
AND WIND SHEAR FOR THE SEVERE WEATHER THREAT.

MINOR LOWLAND FLOODING WILL CONTINUE ALONG THE MISSOURI RIVER
FROM AROUND PLATTSMOUTH DOWNSTREAM THROUGH RULO.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

MINOR FLOODING WILL CONTINUE ALONG THE MISSOURI RIVER FROM AROUND
PLATTSMOUTH DOWNSTREAM THROUGH AROUND RULO INTO THE WEEKEND.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION COULD POSSIBLY BE NEEDED THIS EVENING...BUT
GENERALLY WEST OR NORTHWEST OF THE AREA.

CHERMOK

In the hours before

Local storm report, May 12, 8:58 PM CDT, 1 hour 8 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
858 PM CDT THU MAY 12 2011

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

0840 PM     HAIL             BLUE SPRINGS            40.14N 96.66W
05/12/2011  M1.25 INCH       GAGE               NE   TRAINED SPOTTER

&&

RCHERMOK

Local storm report, May 12, 9:02 PM CDT, 1 hour 4 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
902 PM CDT THU MAY 12 2011

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

0850 PM     TSTM WND DMG     GARRISON                41.18N 97.16W
05/12/2011                   BUTLER             NE   TRAINED SPOTTER

            EST 60 MPH...2-3 INCH TREE BRANCH DOWN

&&

BMAYES

Local storm report, May 12, 9:11 PM CDT, 55 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
911 PM CDT THU MAY 12 2011

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

0911 PM     HEAVY RAIN       SURPRISE                41.10N 97.31W
05/12/2011  M2.90 INCH       BUTLER             NE   TRAINED SPOTTER

&&

Local storm report, May 12, 9:12 PM CDT, 54 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
912 PM CDT THU MAY 12 2011

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

0908 PM     HAIL             3 NE LINCOLN            40.85N 96.65W
05/12/2011  M1.00 INCH       LANCASTER          NE   AMATEUR RADIO

            DIME TO QUARTER SIZE

&&

BMAYES

Local storm report, May 12, 9:13 PM CDT, 53 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
913 PM CDT THU MAY 12 2011

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

0911 PM     FLASH FLOOD      SURPRISE                41.10N 97.31W
05/12/2011                   BUTLER             NE   TRAINED SPOTTER

            BIG BLUE RIVER OUT OF BANKS AT SURPRISE.

&&

Local storm report, May 12, 10:05 PM CDT, 1 minute before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
1005 PM CDT THU MAY 12 2011

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

1005 PM     HEAVY RAIN       MALCOLM                 40.91N 96.87W
05/12/2011  M1.10 INCH       LANCASTER          NE   AMATEUR RADIO

&&

The office that day

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

Issued	Product	Office	Counties	Lasted
May 12, 7:01 PM CDT	Severe Thunderstorm Warning	OAX	Jefferson, Saline	44 min
May 12, 7:15 PM CDT	Severe Thunderstorm Warning	OAX	Butler, Lancaster, Saunders	45 min
May 12, 7:17 PM CDT	Severe Thunderstorm Warning	OAX	Lancaster, Saunders	43 min
May 12, 7:23 PM CDT	Severe Thunderstorm Warning	OAX	Butler, Lancaster, Seward	52 min
May 12, 7:27 PM CDT	Severe Thunderstorm Warning	OAX	Gage	48 min
May 12, 7:52 PM CDT	Severe Thunderstorm Warning	OAX	Butler, Colfax, Platte	38 min
May 12, 8:09 PM CDT	Severe Thunderstorm Warning	OAX	Butler, Seward	36 min
May 12, 8:12 PM CDT	Tornado Warning	OAX	Seward	33 min
May 12, 8:36 PM CDT	Severe Thunderstorm Warning	OAX	Lancaster, Saunders	39 min
May 12, 8:38 PM CDT	Severe Thunderstorm Warning	OAX	Gage, Johnson, Pawnee	52 min
May 12, 8:41 PM CDT	Severe Thunderstorm Warning	OAX	Lancaster	49 min
May 12, 8:45 PM CDT	Flash Flood Warning	OAX	Platte	4 hr
May 12, 8:45 PM CDT	Severe Thunderstorm Warning	OAX	Butler, Lancaster, Saunders, Seward	45 min
May 12, 8:52 PM CDT	Tornado Warning	OAX	Saunders	23 min
May 12, 8:54 PM CDT	Flash Flood Warning	OAX	Butler, Seward	6 hr
May 12, 8:59 PM CDT	Flash Flood Warning	OAX	Lancaster, Saunders	4 hr
May 12, 9:15 PM CDT	Severe Thunderstorm Warning	OAX	Cass, Douglas, Lancaster, Sarpy, Saunders	45 min
May 12, 9:27 PM CDT	Flash Flood Warning	OAX	Lancaster, Saunders	3 hr
May 12, 10:02 PM CDT	Flash Flood Warning	OAX	Douglas, Sarpy, Saunders	3 hr
May 12, 10:32 PM CDT	Severe Thunderstorm Warning	OAX	Douglas, Washington	26 min
May 12, 11:45 PM CDT	Areal Flood Advisory	OAX	Otoe	3 hr

Nearby

Severe Thunderstorm Warnings in Nebraska, 2011 Severe Thunderstorm Warnings in Iowa, 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.