Alert archive / North Carolina / Flash Flood Warnings in 2011

Flash Flood Warning 66, NWS Blacksburg, VA

August 18, 2011Alleghany County, North Carolina

NWS Blacksburg, VA issued this flash flood warning at Aug 18, 2011, 5:17 PM EDT for Alleghany County, North Carolina. It was in force for 5 hr. 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, 5:17 PM EDT (21:17 UTC)
Expired
Aug 18, 2011, 10:20 PM EDT
In force
5 hr
Issued by
NWS Blacksburg, VA
Area
Storm-based polygon
Flood severity
None

County Alleghany County, NC

The radar

The Roanoke radar (KFCX), 97 km from the middle of the area, began a volume at 21:18 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

TimeReportWhereRemark
Aug 18, 5:30 PM EDTFLASH FLOOD1 Ene Sparta, NC18TH STREET WAS CLOSED DUE TO HIGH WATER.

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

The nearest sounding before it

Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 9.3 hours before the alert went out and 123 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, Greensboro/Hi Pt, NC at 12:00Z on 2011-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 257 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Greensboro/Hi Pt, NC at 12:00Z on 2011-08-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 32 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
257 J/kg
Mixed-layer CIN
-74 J/kg
Mixed-layer LCL
1327 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
32 m²/s²
0-3 km storm-relative helicity
-9 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

584 
WGUS51 KRNK 182117
FFWRNK
NCC005-190315-
/O.NEW.KRNK.FF.W.0066.110818T2117Z-110819T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE BLACKSBURG VA
517 PM EDT THU AUG 18 2011

THE NATIONAL WEATHER SERVICE IN BLACKSBURG HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  ALLEGHANY COUNTY IN NORTHWEST NORTH CAROLINA

* UNTIL 1115 PM EDT.

* AT 513 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN FROM A THUNDERSTORM OVER THE WARNED AREA.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO TWIN OAKS
  AND STRATFORD.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...HIGHWAYS AND UNDERPASSES. ADDITIONALLY...COUNTRY
ROADS AND FARMLANDS ALONG THE BANKS OF CREEKS...STREAMS AND OTHER LOW
LYING AREAS ARE SUBJECT TO FLOODING.

MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO
AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY
DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL
ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED
ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.

PLEASE RELAY ANY REPORTS OF FLOODING INCLUDING MUDSLIDES...OR ROAD
CLOSURES TO THE NATIONAL WEATHER SERVICE IN BLACKSBURG BY CALLING
TOLL FREE...1...8 6 6...2 1 5...4 3 2 4. DELAYED REPORTS ARE WELCOME.

&&

LAT...LON 3657 8121 3651 8103 3643 8109 3651 8125

$$

RCS
2 follow-up statements
616 
WGUS71 KRNK 182250
FFSRNK

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE BLACKSBURG VA
650 PM EDT THU AUG 18 2011

NCC005-190315-
/O.CON.KRNK.FF.W.0066.000000T0000Z-110819T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
ALLEGHANY NC-
650 PM EDT THU AUG 18 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1115 PM EDT FOR
ALLEGHANY COUNTY...

AT 638 PM EDT...LOCAL LAW ENFORCEMENT OFFICIALS REPORTED 18TH STREET 
WAS CLOSED DUE TO HIGH WATER FROM HEAVY RAIN THIS AFTERNOON. AS OF 
630 PM...18TH STREET WAS REOPENED. DOPPLER RADAR ESTIMATED 4 TO 6 
INCHES OF RAIN FELL NEAR SPARTA BETWEEN 400 PM AND 600 PM. RUNOFF 
WILL KEEP THE THREAT OF FLASH FLOODING IN THE WARNED AREA INTO THIS 
EVENING. PLEASE RELAY ANY REPORTS OF FLOODING INCLUDING 
MUDSLIDES...OR ROAD CLOSURES TO THE NATIONAL WEATHER SERVICE IN 
BLACKSBURG BY CALLING TOLL FREE...1...8 6 6...2 1 5...4 3 2 4. 
DELAYED REPORTS ARE WELCOME.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO TWIN OAKS AND
STRATFORD

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...HIGHWAYS AND UNDERPASSES. ADDITIONALLY...COUNTRY
ROADS AND FARMLANDS ALONG THE BANKS OF CREEKS...STREAMS AND OTHER LOW
LYING AREAS ARE SUBJECT TO FLOODING.

MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO
AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY
DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL
ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED
ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.

&&

LAT...LON 3657 8121 3651 8103 3643 8109 3651 8125

$$

RCS
794 
WGUS71 KRNK 190220
FFSRNK

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE BLACKSBURG VA
1020 PM EDT THU AUG 18 2011

NCC005-190230-
/O.CAN.KRNK.FF.W.0066.000000T0000Z-110819T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
ALLEGHANY NC-
1020 PM EDT THU AUG 18 2011

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR ALLEGHANY COUNTY...

EARLIER FLOODING HAS ENDED OVER THE WARNED AREA...THUS THE FLASH 
FLOOD WARNING HAS BEEN CANCELLED.

LAT...LON 3657 8121 3651 8103 3643 8109 3651 8125

$$

JH

The office that day

Everything else NWS Blacksburg, VA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 18, 1:43 PM EDTSpecial Weather StatementRNKSurry62 min
Aug 18, 2:45 PM EDTSpecial Weather StatementRNKSurry30 min
Aug 18, 2:48 PM EDTSevere Thunderstorm WarningRNKAlleghany, Surry19 min
Aug 18, 3:38 PM EDTSpecial Weather StatementRNKAlleghany67 min
Aug 18, 3:39 PM EDTSpecial Weather StatementRNKWilkes66 min
Aug 18, 4:10 PM EDTSevere Thunderstorm WarningRNKWilkes45 min
Aug 18, 4:30 PM EDTSevere Thunderstorm WarningRNKWilkes39 min
Aug 18, 5:00 PM EDTSevere Thunderstorm WarningRNKWilkes, Yadkin23 min
Aug 18, 7:03 PM EDTSpecial Weather StatementRNKAshe57 min

Nearby

Flash Flood Warnings in North Carolina, 2011Every 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.