Alert archive / Nebraska / Flash Flood Warnings in 2011

Flash Flood Warning 7, NWS Omaha, NE

May 20, 2011Boone County, Nebraska

NWS Omaha, NE issued this flash flood warning at May 20, 2011, 8:41 PM CDT for Boone County, Nebraska. It was in force for 5 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: May 20, 2011, 8:41 PM CDT (01:41 UTC)
Expired: May 21, 2011, 1:30 AM CDT
In force: 5 hr
Issued by: NWS Omaha, NE
Area: Storm-based polygon
Flood severity: None

County Boone County, NE

The radar

The Grand Island radar (KUEX), 153 km from the middle of the area, began a volume at 01:43 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, 1.7 hours before the alert went out and 156 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: 82 J/kg
Mixed-layer CIN: -6 J/kg
Mixed-layer LCL: 540 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 115 m²/s²
0-3 km storm-relative helicity: 114 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

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

003 
WGUS53 KOAX 210141
FFWOAX
NEC011-210630-
/O.NEW.KOAX.FF.W.0007.110521T0141Z-110521T0630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
841 PM CDT FRI MAY 20 2011

THE NATIONAL WEATHER SERVICE IN OMAHA HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHWESTERN BOONE COUNTY IN NORTHEAST NEBRASKA

* UNTIL 130 AM CDT

* AT 836 PM CDT...LOCAL LAW ENFORCEMENT OFFICIALS REPORTED FLASH 
  FLOODING ACROSS HIGHWAY 52 IN THE PRIMROSE AND CEDAR RAPIDS AREA.  
  THE FLOODING WAS OCCURRING ALONG THE CEDAR RIVER AND LOCAL         
  TRIBUTARIES IN THE AREA ARE ALSO LIKELY FLOODING.  RADAR 
  HAS ESTIMATED THAT 2 TO 3 INCHES OF RAIN HAS FALLEN OVER THE AREA  
  SINCE THIS AFTERNOON AND ANOTHER INCH OR SO IS LIKELY YET THIS     
  EVENING.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...AS WELL AS FARMLAND ALONG THE
BANKS OF CREEKS AND STREAMS. USE ALTERNATE ROUTES AROUND FLOOD PRONE
AREAS.

&&

LAT...LON 4183 9830 4174 9808 4152 9791 4148 9829

$$

CHERMOK

2 follow-up statements

130 
WGUS73 KOAX 210313
FFSOAX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
1013 PM CDT FRI MAY 20 2011

NEC011-210630-
/O.CON.KOAX.FF.W.0007.000000T0000Z-110521T0630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BOONE NE-
1013 PM CDT FRI MAY 20 2011

...FLASH FLOOD WARNING REMAINS IN EFFECT FOR SOUTHWESTERN BOONE
COUNTY UNTIL 130 AM CDT...

AT 1004 PM CDT...LOCAL LAW ENFORCEMENT OFFICIALS REPORTED THAT SOME 
FLOODING CONTINUED ALONG COUNTY ROADS NEAR PRIMROSE AND CEDAR 
RAPIDS.  EARLIER TONIGHT WATER FLOODED ACROSS HIGHWAY 52 IN THE 
AREA. THE FLOODING WAS THE RESULT OF 2 TO 3 INCHES OF RAIN THAT FELL 
LOCALLY ACROSS THE AREA EARLIER IN THE EVENING.  MOST OF THE RAIN 
HAS ENDED FOR TONIGHT...BUT SOME FLOODING COULD CONTINUE INTO EARLY 
SATURDAY.

SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...CEDAR RAPIDS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLOODING IS OBSERVED...ACT QUICKLY. DO NOT
ENTER THE WATER. TURN AROUND AND MOVE UP TO HIGHER GROUND. DO NOT
STAY IN AREAS SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

&&

LAT...LON 4183 9830 4174 9808 4152 9791 4148 9829

$$

CHERMOK

485 
WGUS73 KOAX 210627
FFSOAX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
127 AM CDT SAT MAY 21 2011

NEC011-210642-
/O.EXP.KOAX.FF.W.0007.000000T0000Z-110521T0630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BOONE NE-
127 AM CDT SAT MAY 21 2011

...THE FLASH FLOOD WARNING THAT WAS IN EFFECT FOR SOUTHWESTERN BOONE
COUNTY WILL BE ALLOWED TO EXPIRE AT 130 AM CDT...

EXCESS RUNOFF FROM HEAVY RAIN HAS ENDED OVER THE WARNED AREA. STREAMS
AND CREEKS IN THE WARNED AREA HAVE RECEDED OR WERE BEGINNING TO
RECEDE...ENDING THE FLOOD THREAT. IF FLOODING HAS BEEN OBSERVED...
PLEASE REPORT IT TO YOUR LOCAL LAW ENFORCEMENT AGENCY.

LAT...LON 4183 9830 4174 9808 4152 9791 4148 9829

$$

FOBERT

The office that day

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

Issued	Product	Office	Counties	Lasted
May 21, 2:23 AM CDT	River Flood Warning	OAX	Saline	32 hr
May 21, 2:20 PM CDT	Severe Thunderstorm Warning	OAX	Butler, Colfax, Dodge, Saunders	40 min
May 21, 2:34 PM CDT	Tornado Warning	OAX	Butler, Colfax, Dodge, Saunders	17 min
May 21, 2:56 PM CDT	Severe Thunderstorm Warning	OAX	Burt, Cuming, Thurston	25 min
May 21, 4:55 PM CDT	Severe Thunderstorm Warning	OAX	Butler	35 min
May 21, 5:03 PM CDT	Severe Thunderstorm Warning	OAX	Knox	27 min
May 21, 5:21 PM CDT	Severe Thunderstorm Warning	OAX	Burt, Cuming, Dodge	39 min
May 21, 5:27 PM CDT	Severe Thunderstorm Warning	OAX	Butler, Colfax, Platte	48 min
May 21, 5:54 PM CDT	Severe Thunderstorm Warning	OAX	Colfax, Platte, Stanton	51 min
May 21, 6:04 PM CDT	Severe Thunderstorm Warning	OAX	Butler	26 min
May 21, 6:20 PM CDT	Severe Thunderstorm Warning	OAX	Cuming, Thurston	40 min
May 21, 6:21 PM CDT	Severe Thunderstorm Warning	OAX	Nemaha	24 min
May 21, 6:26 PM CDT	Severe Thunderstorm Warning	OAX	Madison, Platte, Stanton	49 min
May 21, 6:31 PM CDT	Tornado Warning	OAX	Butler	29 min
May 21, 6:44 PM CDT	Severe Thunderstorm Warning	OAX	Cedar, Wayne	33 min
May 21, 6:45 PM CDT	Severe Thunderstorm Warning	OAX	Cuming, Stanton, Wayne	45 min
May 21, 6:50 PM CDT	Severe Thunderstorm Warning	OAX	Cass, Sarpy	40 min
May 21, 6:51 PM CDT	Tornado Warning	OAX	Butler, Saunders	24 min
May 21, 6:57 PM CDT	Flash Flood Warning	OAX	Butler	2 hr

Nearby

Flash Flood Warnings in Nebraska, 2011 Every flash flood 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.