Alert archive / Nebraska / Flash Flood Warnings in 2011

Flash Flood Warning 16, NWS Cheyenne, WY

July 13, 2011Cheyenne County, Nebraska

NWS Cheyenne, WY issued this flash flood warning at Jul 13, 2011, 1:43 AM MDT for Cheyenne County, Nebraska. It was in force for 4 hr. 2 reports 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: Jul 13, 2011, 1:43 AM MDT (07:43 UTC)
Expired: Jul 13, 2011, 5:40 AM MDT
In force: 4 hr
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon
Flood severity: None

County Cheyenne County, NE

The radar

The Cheyenne radar (KCYS), 168 km from the middle of the area, began a volume at 07:46 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
Jul 13, 4:00 AM MDT	FLASH FLOOD	Lodgepole, NE	FLOODING REPORTED IN LODGEPOLE
Jul 13, 4:00 AM MDT	FLASH FLOOD	Sidney, NE	COUNTY ROADS 113 AND 135 FLOODED AND CLOSED IN SPOTS NORTH AND EAST OF SIDNEY. PORTIONS OF ROADS WERE WASHED OUT

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

The nearest sounding before it

Denver, CO (KDNR), launched 00:00Z, 7.7 hours before the alert went out and 150 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: 596 J/kg
Mixed-layer CIN: -61 J/kg
Mixed-layer LCL: 1449 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: -12 m²/s²
0-3 km storm-relative helicity: 256 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.2

Open this sounding in Storm Lab

The text

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

521 
WGUS55 KCYS 130743
FFWCYS
NEC033-131330-
/O.NEW.KCYS.FF.W.0016.110713T0743Z-110713T1330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE CHEYENNE WY
143 AM MDT WED JUL 13 2011

THE NATIONAL WEATHER SERVICE IN CHEYENNE HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  EASTERN CHEYENNE COUNTY IN THE PANHANDLE OF NEBRASKA...

* UNTIL 730 AM MDT

* AT 140 AM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  SLOW MOVING THUNDERSTORMS TRAINING OVER THE SAME AREA WITH VERY 
  HEAVY RAINFALL ACROSS THE WARNED AREA. ANOTHER ONE TO TWO INCHES
  OF RAIN IS EXPECTED OVER THE NEXT 3 HOURS.

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
  OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  SIDNEY...COLTON...DALTON...GURLEY...LODGEPOLE...LORENZO...SIDNEY
  AIRPORT AND SUNOL.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

ADDITIONAL RAINFALL AMOUNTS OF ONE AND A HALF INCHES ARE POSSIBLE IN 
THE WARNED AREA THROUGH 3 AM.

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

&&

LAT...LON 4101 10261 4100 10306 4144 10311 4143 10263

$$

TJT

1 follow-up statement

673 
WGUS75 KCYS 131140
FFSCYS

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
540 AM MDT WED JUL 13 2011

NEC033-131155-
/O.CAN.KCYS.FF.W.0016.000000T0000Z-110713T1330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CHEYENNE NE-
540 AM MDT WED JUL 13 2011

...THE FLASH FLOOD WARNING THAT WAS IN EFFECT FOR EASTERN CHEYENNE
COUNTY IS CANCELLED...

EXCESS RUNOFF FROM HEAVY RAIN HAS ENDED OVER THE WARNED AREA. STREAMS
AND CREEKS IN THE WARNED AREA WERE BEGINNING TO RECEDE BUT MAY 
REMAIN NEAR BANKFULL EARLY THIS MORNING. IF FLOODING HAS BEEN 
OBSERVED...PLEASE REPORT IT TO YOUR LOCAL LAW ENFORCEMENT AGENCY.

LAT...LON 4101 10261 4100 10306 4144 10311 4143 10263

$$

TJT

The office that day

Everything else NWS Cheyenne, WY issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 12, 11:54 PM MDT	Flash Flood Warning	CYS	Banner, Cheyenne, Kimball	5 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.