Alert archive / North Carolina / Flash Flood Warnings in 2012

Flash Flood Warning 38, NWS Blacksburg, VA

July 21, 2012Caswell County, North Carolina

NWS Blacksburg, VA issued this flash flood warning at Jul 21, 2012, 5:37 PM EDT for Caswell County, North Carolina. It was in force for 4 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
Jul 21, 2012, 5:37 PM EDT (21:37 UTC)
Expired
Jul 21, 2012, 9:58 PM EDT
In force
4 hr
Issued by
NWS Blacksburg, VA
Area
Storm-based polygon
Flood severity
None

County Caswell County, NC

The radar

The Roanoke radar (KFCX), 111 km from the middle of the area, began a volume at 21:38 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

Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 9.6 hours before the alert went out and 73 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 2012-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 679 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 2012-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 49 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
679 J/kg
Mixed-layer CIN
-73 J/kg
Mixed-layer LCL
870 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
49 m²/s²
0-3 km storm-relative helicity
69 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.

160 
WGUS51 KRNK 212137
FFWRNK
NCC033-220330-
/O.NEW.KRNK.FF.W.0038.120721T2137Z-120722T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE BLACKSBURG VA
537 PM EDT SAT JUL 21 2012

THE NATIONAL WEATHER SERVICE IN BLACKSBURG HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHEASTERN CASWELL COUNTY IN NORTH CENTRAL NORTH CAROLINA

* UNTIL 1130 PM EDT.

* AT 529 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  VERY HEAVY RAIN FROM A THUNDERSTORM OVER THE WARNED AREA. THIS     
  RAIN WILL FALL ACROSS AREAS WHICH RECEIVED 3 TO 5 INCHES OF RAIN   
  EARLIER THIS AFTERNOON. MANY CREEKS AND DITCHES ACROSS THE WARNED  
  AREA MAY BE AT BANKFULL...AND THIS NEXT ROUND OF RAIN WILL LIKELY  
  CAUSE THESE WATER WAYS TO FLOOD.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO SEMORA...
  PROVIDENCE...GATEWOOD...BLANCH AND MILTON.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

ADDITIONAL RAINFALL AMOUNTS OF 1 TO 2 INCHES ARE POSSIBLE IN THE 
WARNED AREA.

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.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY. MOVE TO HIGHER GROUND.

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 3644 7942 3654 7942 3654 7913 3645 7913
      3645 7914 3644 7914 3643 7915

$$

16
2 follow-up statements
435 
WGUS71 KRNK 220036
FFSRNK

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE BLACKSBURG VA
836 PM EDT SAT JUL 21 2012

NCC033-220330-
/O.CON.KRNK.FF.W.0038.000000T0000Z-120722T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CASWELL NC-
836 PM EDT SAT JUL 21 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1130 PM EDT FOR
NORTHEASTERN CASWELL COUNTY...

AT 829 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THAT HEAVY RAIN HAS LEFT THE AREA. HOWEVER...RAINFALL AMOUNTS OF 6 
TO 8 INCHES FELL ACROSS PARTS OF NORTHERN CASWELL COUNTY...WHICH 
WILL RESULT IN OVERFLOWING CREEKS AND ROADSIDE DITCHES AND POSSIBLY 
SPILL ONTO ROADWAYS.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO SEMORA...
PROVIDENCE...GATEWOOD...BLANCH AND MILTON

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DO NOT ALLOW CHILDREN TO PLAY NEAR CREEKS AND DRAINAGE DITCHES WHEN 
FULL. THE RAPID FLOW OF WATER MAY BE POWERFUL ENOUGH TO CARRY THEM 
AWAY SHOULD THEY FALL IN.

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

PLEASE RELAY ANY REPORTS OF FLOODING 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 3644 7942 3654 7942 3654 7913 3645 7913
      3645 7914 3644 7914 3643 7915

$$

16
720 
WGUS71 KRNK 220158
FFSRNK

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE BLACKSBURG VA
958 PM EDT SAT JUL 21 2012

NCC033-220207-
/O.CAN.KRNK.FF.W.0038.000000T0000Z-120722T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CASWELL NC-
958 PM EDT SAT JUL 21 2012

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR NORTHEASTERN
CASWELL COUNTY...

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

LAT...LON 3644 7942 3654 7942 3654 7913 3645 7913
      3645 7914 3644 7914 3643 7915

$$

16

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 21, 1:47 PM EDTSpecial Weather StatementRNKPerson43 min
Jul 21, 2:06 PM EDTAreal Flood AdvisoryRNKCaswell3 hr
Jul 21, 3:33 PM EDTSpecial Weather StatementRNKCaswell57 min
Jul 21, 4:40 PM EDTSpecial Weather StatementRNKRockingham65 min
Jul 21, 5:04 PM EDTSevere Thunderstorm WarningRNKCaswell, Rockingham56 min
Jul 21, 5:15 PM EDTSevere Thunderstorm WarningRNKCaswell60 min
Jul 21, 5:40 PM EDTSevere Thunderstorm WarningRNKCaswell, Rockingham65 min

Nearby

Flash Flood Warnings in North Carolina, 2012Every flash flood warning in 2012

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.